Difference between revisions of "Computer Aided Design Competition"

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= Pre-Lab =
<!--= Pre-Lab =
<br /><font color="red"><b>'''You must visit the MakerSpace before this lab and complete safety training along with 3D Printing training. EG has organized special training for EG students. Sign up [https://orgsync.com/163395/events?view=upcoming.| here]'''</b></font>
<br /><font color="red"><b>Please visit the MakerSpace before this lab and complete their Safety Orientation. Sign up for sessions provided specifically for EG1004 students [https://orgsync.com/163395/events?view=upcoming. here]'''</font> If you have already completed the Safety Orientation, please fill out [https://forms.gle/3B3p7ZujPEBAzY6w6 this form] to receive credit. There will be a 20 point penalty on the lab report for not completing this training before the beginning of this lab.</b>-->
<br /><font color="red"><b>''' There will be a 20% penalty for not completing the training. '''</b></font>  


In order to have an understanding of this lab and be able to complete it in a timely manner it is important you view the videos that go in accordance with this lab.
<font color="red">'''Please review the [https://manual.eg.poly.edu/images/2/2b/Introduction_to_CAD_Guide.pptx CAD Guide] presentation that explains the fundamentals of CAD software prior to performing this lab. The presentation is listed underneath the title Lab 2 on the EG1004 Lab Manual'''.</font>
The required videos are on the main page of the manual.


= Objectives =
=== Objective ===
The experimental objectives of this lab are:
* Understand the simulation capabilities of Fusion 360, a common computer-aided design (CAD) software
* Use the basic of modeling techniques in Revit
* Understand product evaluation and minimal design concepts


Using Fusion 360 to remake a poorly design piece will introduce students to a widely used CAD modeling software and integrate common engineering techniques including concepts of safety factor, static stress, product evaluation, and minimal design. This will lead to an in house competition between all designs to determine which is the most successful and useful of a part. 
The objective of this lab is to use Autodesk Fusion to modify a three-dimensional structure to increase its minimum safety factor while minimizing any increase in volume. The structures will be evaluated in competition using a competition equation that depends on the change in the structure’s safety factors and volumes.
Designing an apartment in Revit will teach the basics of the program and give an introduction to architectural design problems. The apartment designs will be judged in a competition by your recitation professor.


= Overview =
=== Overview ===
== Fusion 360 ==
==== Computer-Aided Design ====
Fusion 360 is a cloud-based software (remote servers hosted via the internet that is used to process, store, and compute data) Computer Aided Design (CAD)/ Computer Aided Manufacturing (CAM)/ Computer Aided Engineering (CAE) tool that allows engineers to make precisely scaled drawings. These drawings are then turned into 3D models where they can be used to visualize concepts through photorealistic renderings and simulate how a design performs in real-world situations. Fusion 360 is a software very similar to Solidworks in the tasks you can accomplish on it as well as the layout and the tools.  
Computer-aided design (CAD) uses computer software to create, modify, or analyze the designs of 3D products (Omaia et al., 2024). Across engineering industries, CAD software allows engineers to create dimensioned, scaled drawings that allow them to explore and refine ideas safely and cost effectively (Berselli et al., 2020). Autodesk Fusion, AutoCAD, Revit, Dassault Systèmes, SolidWorks, and Sketchup Free are examples of CAD software. This exercise will use Autodesk Fusion to explore the use of CAD software to evaluate and improve the safety of a design.


The two tabs that will be used in this experiment are “Model” and “Simulation”.
==== Design Considerations ====
The safety of a structure is often defined by a metric called the '''safety factor''' (Musto, 2012). The safety factor is defined as the ratio of how much stronger a material is than the expected load. It is the measure of the load a material can sustain before permanent deformation or fracture. A common, acceptable safety factor is at least 3. Any value below that will likely lead to structural failure.


In the “model” section you will find three important sections; “Sketch”, “Create,and “Modify”
Every design decision made by an engineering team can impact the safety factor of a structure. This begins with the choice of material used for the project. The '''Young’s modulus''', or modulus of elasticity, of a material is the measure of its tendency to deform when a force is applied in the axial direction. The '''yield strength''' of a material is the point at which the material begins to deform plastically, and the shape of the material is permanently altered. The '''Ultimate Tensile Strength (UTS)''' of a material is the maximum stress that the material can withstand before structurally failing, which usually involves bending permanently or breaking (Table 1).


* '''Sketch''' is the most basic tool that can be used in the software. It is used to create the shapes that will act as the bases for all 3D models. When first sketching the shapes they do not have to be true to their dimension or scale, by using the '''Dimension''' tool and '''Geometric Constraints''' tool the base shape and 3D model can be edited without starting over.


[[File:Figure_1.PNG|500px|thumb|center|Figure 1: Before and after of sketch when using '''Dimensions''' tool]]
::{| class="wikitable"
|+Table 1: Allowed Materials and their Properties
|-
!'''Material'''
| '''Young's Modulus (GPa)'''
| '''Yield Strength (MPa)'''
| '''Ultimate Tensile Strength (MPa)'''
|-
!'''Aluminum (Al)'''
| 69
| 275
| 310
|-
!'''Steel'''
| 200
| 207
| 345
|-
!'''Copper (Cu)'''
| 118
| 33
| 210
|-
!'''Lead (Pb)'''
| 14
| 9
| 18
|}


* '''Create''' is the tab where the 3D model begins to take shape. Tools such as extrude, cut and sweep,  are used to give direction and depth to the 3D model The tools used in this experiment will be the '''Extrude''' and '''Cut''' tool as well as the '''Sweep''' tool. '''Extrude''' projects the initial sketch outward to create a model. '''Cut''' removes from the model a predetermined shape to the desired depth. The '''sweep''' tool creates a 3D model of a predetermined surface (sketch) along a specific path. Although this tool is more efficient than just creating multiple shapes and cutting it can be a bit challenging and so creating the shapes you want and then using a cut for this lab should be sufficient as the shapes used for supports are not more than 4 sided shapes.
==== Autodesk Fusion ====
In this lab, Autodesk Fusion will be used to modify a part and evaluate its safety factor. Autodesk Fusion is a cloud-based CAD software; it uses remote servers hosted via the Internet to process, store, compute, create, and analyze 3D models of structures.


*'''Modify''' contains '''fillet''' which creates a curve from an edge or corner where you can choose the radius of the curve, this can allow for a load better distributed along a surface and increase structural support.
The two workspaces in Fusion that will be used in this experiment are '''Design''' and '''Simulation''' (Figure 1). The '''Design''' workspace creates mechanical designs that contain information about geometric constraints, and the '''Simulation''' workspace simulates applied loads on a design to observe the design's performance under those loads.


[[File:Figure_2.PNG|500px|thumb|center|Figure 2: Example of a '''Sweep''']]
[[File:Lab 4 Figure 1.PNG|136px|thumb|center|Figure 1: Fusion Workspaces]]


'''Simulation''' is a very important tool that can run many different simulations in order to test how a part will do in real-world situations. “Static stress” analyzes the deformation, stress, and safety factor in a model from structural loads and constraints. These assumptions are based off a linear response to stress when the load being applied is known and is constant. Using the results you can determine whether a design will deform excessively or fail (break) from the loads applied. In order to run the tests, conditions need to be set on the model.
There are two tabs in the '''Design''' workspace: '''Create''' and '''Modify'''. The '''Create''' and '''Modify''' tabs contain the functions needed for sketching and building a 3D model. They create and modify sketches when in Sketch mode (Figure 2).
* Constraints consist of fixed, pinned, and frictionless support reactions that prevent motion in specific directions. '''Fixed constraints''' prevent all motion and displacement of a part, this would mimic a screw holding a part in place. Pinned support prevents the movement in radial, axial, and/or tangential directions but allows a part to rotate. '''Frictionless''' constraints prevent movement normal to the surface, this mimics a wall or floor prevent motion perpendicular to the surface.
* Mesh is a boundary along the model made up of polygons where that determine the precision of the test. At every vertex, the test is run and provides the results at each point. The more polygons the more precise but the longer it takes to produce accurate results. (always generate new mesh when a part is altered)
* Load is the force being applied to the model. The force is characterized by the direction, the point of application, and the magnitude being applied.


'''Safety Factor''' is a term describing how much stronger the system is than it needs to be for an intended load. It is the measure of how much load an object can sustain before permanent deformation or fracture. A common acceptable safety factor is at least 3, anything below that is unacceptable and will likely lead to the failure of the object.
[[File:Lab 4 Figure 2.PNG|600px|thumb|center|Figure 2: Create and Modify Tabs in Sketch Mode]]


It is important to have a very brief understanding of the physical properties of certain materials that dictate how they behave under applied loads. Modulus of elasticity is the measure of the stiffness of an object. It is described as the tendency of an object to deform axially when a force is being applied in and that axial direction. Yield strength is the point at which the material begins plastic deformation begins and the shape of the object is permanently deformed. Lastly, the Ultimate Tensile Strength (UTS) is the maximum stress that a material can withstand before finally failing (Bending permanently or breaking).
A <b>Sketch</b> creates the 2D shapes that are the bases for all 3D models. When first sketching the shapes, they do not have to have accurate dimensions or scale. Using the <b>Sketch Dimension</b> tool and the <b>Constraints</b> functions, the base shape and 3D model can be edited without starting over (Figure 3).


== Autodesk Revit ==
[[File: Lab 1 Figure 3.PNG|600px|thumb|center|Figure 3: Before (Left) and After (Right) of Sketch Using the Sketch Dimension Tool]]
Autodesk Revit is a building modeling software for architects, landscape architects, civil engineers, structural engineers, and contractors developed by Autodesk. Revit allows users to design buildings and other architectural structures in 3D while allowing for 2D drafting elements. Revit can be used to easily create various home layouts from the floor plan, such as structural, electrical, plumbing, and HVAC (heating, ventilation, and air conditioning) plans, as well as design many other things.


The floor plan is the fundamental layout of any building. It is essentially the skeleton of the structure. It contains all walls, windows, and entrances to the structure and can also be furnished when being used demonstrative purposes. Different walls are used for different purposes. When designing a house, most of the interior walls are not as thick as exterior walls or walls separating public from private locations. Blueprint plans are often not furnished but to account for this architects and designers specify what the specific home in the area represents.
Once a sketch is complete, the '''Create''' and '''Modify''' tabs are also used to generate the 3D model (Figure 4).


The electrical plan will be a part of the floor plan and demonstrates the positions of all of the light fixtures and electrical appliances such as refrigerators, light switches and wires connecting lights to switches.
[[File:Lab 4 Figure 4.PNG|600px|thumb|center|Figure 4: Create and Modify Tabs in Model Mode]]


= Competition Specifications for Fusion 360 =
The <b>Extrude</b>, <b>Sweep</b>, and <b>Loft</b> tools are used to give direction and depth to the 3D model. <b>Extrude</b> projects the initial sketch outward to create a model. The <b>Sweep</b> tool creates a 3D model of a predetermined surface (profile) along a specific path. The <b>Loft</b> tool creates a 3D extrusion to connect two profiles of any shape (Figure 5). The <b>Sweep</b> and <b>Loft</b> tools are particularly useful for creating extrusions at an angle.  
* The redesigned part must not contain more than '''double''' the volume of the original part.
* For the part to be successful it must test for a safety factor of at least 3.
* You may not alter the applied forces, the fixed point constraints, and you cannot erase/alter the part of the model highlighted in red only add supports. It is important that the thickness of the base is not altered as you are not learning by doing this, and you are altering the proportions of the original part. However, the supports can be altered as that does not take away or add from the base of the model.
* The winning team will receive extra credit toward their lab report grade for this lab.


[[File:Figure_3.PNG|500px|thumb|center|Figure 3: The Competition Ratio]]
[[File:fusion_tools.png|600px|thumb|center|Figure 5: Examples of Extrude (Left), Sweep (Middle), and Loft (Right)]]


= Competition Specifications for Revit =
The [https://drive.google.com/file/d/1r7YxGTRdPiTMHNy8IZnZnf8oXVBsU_FG/view?usp=sharing Loft/Sweep Tutorial video] demonstrates how to use these tools. Table 1 shows common Fusion shortcuts.
It is the year 2012 and you have just been contracted by New York City Mayor Bloomberg to solve a problem for many families; today, there are 1.8 million one- and two-person households in our city, but there are only about 1 million studio and one-bedroom apartments. Your task is to create a 350-400 square foot apartment for residents/college students. This apartment should be furnished to a certain extent. It should contain a bathroom, a bed, a kitchen, a table, and a desk. Your job is to create an apartment with sufficient lighting (at least 1 window) and space so that it has all of the bare essentials. You will be tasked with creating:
* A 350-400 square foot floor plan layout of the entire apartment
* An electrical plan for the entire apartment
** (45-60 minutes for this)
* Your recitation professor will be reviewing all apartment designs and award extra credit to the group with the best design.
* The winning team will receive extra credit toward their presentation grade for this lab.


= Design Considerations =
<center>
===Fusion 360===
{| class="wikitable"
* You '''CANNOT''' just add a long or large block, you must try to add some intuition.
|+ Table 2: Common Fusion Shortcuts
* Try thinking about bridges, cranes and other real-world systems with structural support?
!Command!!Windows Key Combination!! Mac Key Combination
* What material will help increase the safety factor of the predetermined part?
|-
* Using your knowledge of Lab 2 (Boom Construction) how can you modify these parts to support higher loads.
|<center>Pan</center>||<center>Hold Middle Mouse Button</center>||<center>Hold Middle Mouse Button</center>
* Although a specific tool such as sweep is more efficient it is not necessarily the best approach, especially for beginners. Try what you know you can do.
|-
===Revit===
|<center>Zoom</center>||<center>Roll Middle Mouse Button</center>||<center>Roll Middle Mouse Button</center>
* How well was space maximized in this very small apartment?
|-
* Was necessary storage added?
|<center>Orbit</center>||<center>Hold Shift + Middle Mouse Button</center>||<center>Hold Shift + Middle Button</center>
* Is the layout coherent and creative?
|-
* Could a human comfortably live here?
|<center>Undo</center>||<center>Ctrl + Z</center>||<center>Command + Z</center>
|-
|<center>Redo</center>||<center>Ctrl + Y</center>||<center>Command + Z + Shift</center>
|-
|<center>Copy</center>||<center>Ctrl + C</center>||<center>Command + C</center>
|-
|<center>Paste</center>||<center>Ctrl + V</center>||<center>Command + V</center>
|-
|<center>Cut</center>||<center>Ctrl + X</center>||<center>Command + X</center>
|-
|<center>Extrude</center>||<center>E</center>||<center>E</center>
|-
|<center>Move</center>||<center>M</center>||<center>M</center>
 
|}</center>


= List of Fusion and Revit important shortcuts/hotkeys/notes =
The <b>Timeline</b> function located at the bottom of the screen contains a record of the design history that can be modified or manipulated. The controls located to the left can be used to visit previous actions (Figure 6). The middle button will play the design history as an animation. The gray slider on the timeline can be dragged to different areas to show the design at a given stage. Actions can also be removed from the timeline and the design will automatically update itself if errors do not occur later in the timeline.


===Fusion 360===
[[File:Timeline_function.png|600px|thumb|center|Figure 6: Timeline Function]]
* L- line
* R- Rectangle
* C- circle
* D- Dimension
* F- Fillet


===Revit===
The <b>Simulation</b> workspace can run simulations to test how a design will perform under real-world conditions. A <b>Static Stress</b> simulation, for example, analyzes the deformation, stress, and safety factor of a design from structural loads and constraints. The assumptions used in the simulationare based on a linear response to stress when the load being applied is known and constant. The results determine if a design will deform excessively or fail (break) from the loads applied. To run the tests, loads and constraints are placed on the design.
* WT creates windows for multiple views
* WN inserts window
* DR inserts door
* CM inserts components/furniture/appliances


= Materials and Equipment =
'''Constraints''' consist of fixed, pinned, and frictionless support options that prevent motion in specific directions. Fixed constraints prevent all motion and displacement of a part (Figure 7). This would mimic a screw holding a part in place. A pinned support prevents movement in radial, axial, and/or tangential directions, but allows a part to rotate. Frictionless constraints prevent movement normal to the surface. This mimics a wall or floor to prevent motion perpendicular to the surface.
* a lab PC
* Fusion 360
* Revit


{| class="wikitable"
[[File:Lab 4 Figure 6.PNG|600px|thumb|center|Figure 7: Example of Fixed Constraints]]
|-
 
!'''Material'''
A '''load''' is the force being applied to the design (Figure 8). The force is characterized by the direction, the point of application, and the magnitude of the force being applied.
| Aluminum
 
| Steel
[[File:Lab 4 Figure 8.PNG|600px|thumb|center|Figure 8: Example of Loads]]
| Copper
 
| Lead
A <b>Mesh</b> is a boundary along the design made up of polygons that determine the precision of the analysis test (Figure 9). The analysis is run at every vertex. More polygons in the mesh would deliver more precise results with longer simulation time. When a part is altered, it is essential to regenerate the mesh.
| Titanium
 
|-  
[[File:Lab 4 Figure 7.PNG|600px|thumb|center|Figure 9: Example of a Mesh]]
!'''Modulus of Elasticity (MPa)'''
 
| 68,900
== Materials and Equipment ==
| 210,000
* A lab PC
| 117,500
* Autodesk Fusion
| 14,000
 
| 102,810
==Procedure ==
|-
 
!'''Yield Strength (MPa)'''
=== Part 1. Setting up the File ===
| 275
# Launch AutoDesk Fusion, click '''Create Account''', and fill in the information. Important: Make sure to use an NYU email (Figure 10).
| 207
 
| 33.3
[[Image:Lab 1B.jpg|thumb|center|600px|Figure 10: Fusion New File Options]]
| 8.96
 
| 275.6
=== Part 2. Learning Exercise ===
|-
The following activity will be performed prior to the CAD competition to allow students to familiarize themselves with the software.
!'''Ultimate Tensile Strength'''
# Download the following [https://manual.eg.poly.edu/images/c/c7/ScrewedBracket.zip Screwed Bracket] from the manual.
| 310
# Change the workspace from '''Simulation''' to '''Design''' in the top-leftmost drop down. Set the units of the drawing to millimeters. The '''Units''' setting is found in the '''Browser''' on the left side of the window under '''Document Settings'''.
| 345
# Select one of the inner faces and start a 2D Sketch by clicking '''Create Sketch''' (Figure 11). [[Image:2D sketch on face.png|thumb|center|600px|Figure 11: Creating a 2D Sketch on a Face]]
| 210
# Create a '''Center Diameter Circle''' with a diameter of '''14 mm''' by clicking on the center of the existing circular cut. Click '''Finish Sketch''' (Figure 12). [[Image:Sketching a circle.png|thumb|center|600px|Figure 12: Sketching a Circle]]
| 18
# Go to '''Create → Extrude''', which will be used to create a cylinder. Select both contours (Figure 13). [[Image:Creating a cylinder.png|thumb|center|600px|Figure 13: Creating a Cylinder]]
| 344.5
# Change the '''Extent Type''' to '''To Object'''. Select the opposite inner face (Figure 14). Make sure the operation is set to '''Join'''. [[Image:Extruding circle to face.png|thumb|center|600px|Figure 14: Extruding Circle to Face]]
|}
# Select the outer base face as show in the image from Step 8. Select the '''2-Point Rectangle''' from the '''Sketch''' section of the toolbar (Figure 15). [[Image: Lab 1B4 V2.jpg|thumb|center|400px|Figure 15: Point Rectangle]]
# Draw a '''10 mm x 6 mm''' rectangle starting by clicking once at one of the vertices of the flat border (Figure 16) to place one point of the rectangle and click one more time to place the second point of the rectangle. The lengths can be typed in before placing the second point of the rectangle (switching which value is changed is done using the Tab key). Press '''Finish Sketch'''. [[Image: Dimensions of rectangle.jpg|thumb|center|600px|Figure 16: Dimensions of Rectangle]]
# Select the perpendicular face nearest to the rectangle (drawn in the previous step) and start a 2D Sketch. Draw a '''10 mm x 4 mm''' rectangle '''8 mm''' from the base. The horizontal side of the rectangle must be parallel to the previous sketch (Figure 17). To accurately measure the '''8 mm''' from the base, select the '''Sketch Dimension''' tool. Then select the bottom horizontal edge of the rectangle and the edge shown in the purple image below, then move the cursor to the right, click, and the dimension should show up. Then edit the measurement to '''8 mm'''. [[Image:Second rectangle dimensions.png|thumb|center|600px|Figure 17: Dimensions of Second Rectangle]] 
# Next, align the new rectangle with the one previously drawn. Use '''Constraints → Collinear''', and select the left line of the lower rectangle then the left side of the new rectangle as shown in Figure 18. Then select '''Finish Sketch'''.  [[Image:Collinear.png|thumb|center|600px|Figure 18: Collinear Constraints]]
# Go to '''Create → Loft'''. Select the previous two rectangles as '''Profiles'''. Make sure to scroll down and change '''Operation''' to '''New Body''', or Step 12 will not work properly. (Figure 19). [[Image:Lofting a new body.png|thumb|center|400px|Figure 19: Lofting a New Body]]
# Click on '''Construct → Midplane''' and select both of the inner walls (Figure 20). [[Image:Midplane.png|thumb|center|600px|Figure 20: Midplane]]
# Go to '''Create → Mirror'''. Select the '''Loft''' as the Object and the Plane as the '''Mirror Plane''' (Figure 21). [[Image:Mirroring steps.png|thumb|center|600px|Figure 21: Mirroring Steps]]
# This part should look like Figure 22. [[Image:Mirrored loft.png|thumb|center|400px|Figure 22: Mirrored Loft]]
# Select the central base and start a '''2D Sketch'''. Draw two 5 mm '''Center Diameter Circles''' with the origin on the center line '''8 mm''' from the edge (Figure 23). Finish the '''Sketch'''. [[Image:Dimensions circles.png|thumb|center|400px|Figure 23: Dimensions Circles]]
# Start a 2D Sketch on the midplane. Click on '''Create → Arc → 3 Point Arc'''. Place the first and the second points in the centers of each of the circles created in the previous step, as shown in Figures 24-25. [[Image:Creating arc 1.png|thumb|center|400px|Figure 24: Creating Arc]] [[Image:Creating arc 2.png|thumb|center|400px|Figure 25: Creating Arc]]
# Place the third point so that your arc looks somewhat similar to the figure below. You may need to adjust your view so it is oriented as shown in the figure below. Using '''Create → Sketch Dimension''' select one of the end points and the third arc point, drag the dimension straight up, as shown in Figure 26 and set it to be '''9 mm'''. If the arc endpoints are shifted, use '''Constraint → Coincident''' on each arc endpoint and the center of their respective circles. Click '''Finish Sketch'''. [[Image:Creating arc 3.png|thumb|center|400px|Figure 26: Creating Arc]]
# Go to '''Create → Sweep'''. Select the two circles created in the previous step as '''Profiles''' and select the Arc as the '''Path'''. Go to '''Operation''' and choose '''New Body''' (Figure 27). [[Image:Creating loft.png|thumb|center|400px|Figure 27: Creating Sweep]]
# It should look like Figure 28. Save the design. [[Image:Finished loft.png|thumb|center|600px|Figure 28: Finished Loft]]
# Create a '''New Design''' and make a '''2D Sketch''' by selecting any plane and create a rectangle '''5 mm x 26 mm''', as seen in Figure 29. [[Image:Rectangle sketch.png|thumb|center|400px|Figure 29: Rectangle Sketch]]
# '''Extrude''' the rectangle by '''1 mm''' (Figure 30). [[Image:Extruding rectangle.png|thumb|center|500px|Figure 30: Extruding Rectangle]]
# A vector graphics file will be used in the DXF format provided by NYU. In the future, a logo can be designed using the '''Sketch''' tool. Download the  [https://manual.eg.poly.edu/images/6/60/Tandon_long_white.zip Tandon Logo DXF File] (this logo was converted from the file provided on NYU's identity page). 
# The downloaded ZIP folder must be extracted. Select '''Insert DXF''' under the '''Insert''' section of the toolbar (Figure 31). [[Image:Insert dxf tool.png|thumb|center|500px|Figure 31: Insert DXF Tool]]
# The '''Insert DXF''' information dialog will appear on the right side of the window. For the '''Plane/Sketch''', select the top surface (Figure 32). [[Image:Selected top surface.png|thumb|center|600px|Figure 32: Selected Top Surface]]
# Click the folder icon next to the '''Select DXF''' file to upload the Tandon Logo DXF File. The logo should appear (figure 33). [[Image:Imported dxf logo.png|thumb|center|600px|Figure 33: Imported DXF Logo]]
# Move the logo away from the origin by dragging it with your mouse (Figure 34). Alternatively, highlight the entire logo, and use the '''Modify → Move/Copy''' tool to move it. [[Image:Relocated dxf logo.png|thumb|center|600px|Figure 34: Relocated DXF Logo]]
# If the Tandon Logo imports incorrectly, as shown in Figure 35, follow Steps 28-29. Otherwise, skip to Step 30. [[Image: Incorrect tando logo orientation.png|thumb|center|600px|Figure 35: Incorrect Tandon Logo Orientation]]
# Select the '''Modify → Move/Copy''' tool. For '''Move Object''', select sketch objects. For '''Selection''', click and drag to select the entire Tandon logo. For '''Move Type''', select rotate. For '''Axis''', select the top horizontal line and set the angle to '''180°''', as seen in Figure 36. [[Image: Flip about the horizontal line.png|thumb|center|600px|Figure 36: Flip About the Horizontal Line]]
# Repeat Step 21, but for '''Axis''', select the right vertical line and set the angle to be '''180°''' (Figure 37). [[Image: Flip about the vertical line.png|thumb|center|600px|Figure 37: Flip About the Vertical Line]]
# The imported Tandon logo is shown in Figure 38. [[Image: Imported tandon logo.png|thumb|center|600px|Figure 38: Imported Tandon Logo]]
# The vertical bar and Tandon School of Engineering portions of the logo are not needed. Select the bar and text to the right by clicking and dragging (Figure 39). Delete this portion with the '''Delete''' key on the keyboard (not '''Backspace'''). [[Image:Tandon to delete.png|thumb|center|600px|Figure 39: Tandon to Delete]]
# The logo must be scaled to fit the part. A base point must be selected to scale the sketch. The midpoint of the line on the right side of the box around the torch will be used as the base point, so a point must be placed there first.
# Before placing a point, the sketch must be in editing mode. A sketch is in editing mode when the background turns into guidelines, and '''Finish Sketch''' appears at the top right of the window. Edit the logo by selecting '''Browser → Sketches''' and double-clicking on the tandon_logo_white sketch (Figure 40). [[Image:Browser.jpg|thumb|center|600px|Figure 40: Sketches in Browser]]
# Select the '''Create → Point''' tool. Place a point at the midpoint of the right side of the box around the torch (Figure 41). This is the base point.[[Image:Midpoint on box.png|thumb|center|400px|Figure 41: Midpoint on Box]]
# Right click the bottom left corner point of the box around the torch, When selected on the correct point, select '''Delete Coincident''' (Figure 42). You may also need to repeat this for the lines connected to the point. [[Image:Delete coincident.png|thumb|center|600px|Figure 42: Delete Coincident]]
# Select the '''Modify → Sketch Scale''' tool. The '''Sketch Scale''' information dialog will appear on the right hand side of the window. For the '''Entities''', circle the entire logo by clicking and dragging. Do not select the midpoint created in Step 34. If the midpoint was selected, clicking on the point again will unselect it.
# Switch to '''Point''' and select the midpoint created in Step 34 (Figure 43). [[Image:Select midpoint.png|thumb|center|600px|Figure 43: Select Midpoint]]
# In the '''Sketch Scale''' window, a third option will appear as '''Scale Factor'''. enter a scaling factor of '''4.5''' and click '''OK''' (Figure 44). [[Image:Scale factor.png|thumb|center|300px|Figure 44: Scale Factor]]
# Drag and re-locate the logo so it fits cohesive with the sizing. It should look like the logo in Figure 45. [[Image:Final logo.png|thumb|center|600px|Figure 45: Final Logo]]
# Create a 2D sketch on one of the main faces where the logo was inserted. Go to '''Create → Text'''. Make the box smaller than the face, as shown in Figure 46. Type in the designer's name and format it so it is '''Bold''' and will be visible and cohesive with the size of the part. Some recommended setups are shown in Figure 46. [[Image:Text tool.png|thumb|center|600px|Figure 46: Text Tool]]
# After writing, finish the sketch. It should look like Figure 47. [[Image:Recommended dimension.png|thumb|center|600px|Figure 47: Recommended Dimension for Text]]
# The design must be cut into the base. To do this, the '''Extrude''' tool will be used.
# To cut the design, select '''Create → Extrude on the toolbar. The '''Extrude''' information dialog will appear on the right hand side of the window. Select the design profile, which is the area around the torch and each of the letters.
# In the '''Extrude''' window, scroll down to '''Operation''', and select '''Cut'''. Then set the '''Distance''' to '''-0.2 mm''' (Figure 48). Click '''OK'''. Save the design and return to the Bracket. [[Image:Engraved part.png|thumb|center|600px|Figure 48: Engraved Part]]
# The final model is shown in Figure 49. [[Image:Final model.png|thumb|center|600px|Figure 49: Final Model]]
# An assembly between the Plate and Bracket must be made. The Bracket file will be used. In this case, the engraved Plate will be the one floating, which means that it will be the one moving to arrange the pieces in the desired order. In the Bracket file, click on '''Show Data Panel''' in the top left corner, as shown in Figure 50. [[Image:Show data panel.png|thumb|center|200px|Figure 50: Show Data Panel]]
# Once opened, the preview of the Plate should be visible (Figure 51). [[Image:Preview.png|thumb|center|600px|Figure 51: Preview]]
# Click and drag the Plate from the left to the right, where the main screen with the part is. Drop the Plate here. It should look like Figure 52. Press '''OK'''. [[Image:Imported plate.png|thumb|center|600px|Figure 52: Imported Plate]]
# Both parts must be listed as components to create Arrangements between them. The Plate was imported as a component already, now the main part is the only one missing. To do this, right click on '''Bodies''' and select '''Create components''' from '''Bodies''' (Figure 53). This will create four different components. [[Image:Convert to bodies.png|thumb|center|300px|Figure 53: Convert to Bodies]]
# Click on '''Modify → Move/Copy''' and switch from '''Bodies''' to '''Components''', as seen in Figure 54. [[Image:Option selection.png|thumb|center|300px|Figure 54: Option Selection]]
# Select the midpoint of the Plate (Figure 55). [[Image:Selecting for orientation.png|thumb|center|600px|Figure 55: Selecting for Orientation]]
# Modify the Plate so it matches the orientation on Figure 56 by clicking the round circles and rotating it. Press '''OK'''. [[Image:Orientation.png|thumb|center|400px|Figure 56: Orientation]]
# The position of the Plate needs to be exact. Go to '''Modify → Align''' (Figure 57) and click the back of the engraved Plate and the lower wall of the part. [[Image:Align feature.png|thumb|center|600px|Figure 57: Align Feature]]
# The order matters as it will move one part to the other. If the part is oriented incorrectly, click on '''Flip''' and then '''OK'''. It should look like Figure 58. [[Image:Correct direction.png|thumb|center|600px|Figure 58: Correct Direction]]
# Use the '''Align''' feature again and press the left border of the Plate and the inner border of the left wall of the part, as shown in Figure 59. [[Image:Border alignment 1.png|thumb|center|600px|Figure 59: Border Alignment]]
# Do the same with the bottom border of both parts, as shown in Figure 60. [[Image:Border alignment 2.png|thumb|center|600px|Figure 60: Border Alignment]]
# If the plate is oriented incorrectly, use the '''Flip''' option to re-orient the Plate.
# At the end, it should look like Figure 61.[[Image:End result.png|thumb|center|600px|Figure 61: End Result]]
 
== Part 3. Fusion Competition ==
This portion of the lab is a competition that requires teams to redesign an unsafe part to have a minimum safety factor. The competition rules are listed below. The winner of the competition will receive extra credit as detailed in the [[EG Grading Policy | Grading Policy.]]
=== Competition Rules ===
*The redesigned part must have a safety factor of at least 3
*The redesigned part must not have more than double the volume of the original part
*The applied forces and fixed constraints cannot be altered
*The thickness of the base and the proportions of the original part cannot be altered
*The supports can be altered if and only if they do not take away from or add to the base of the part
*Only aluminum, steel, copper, or lead may be used when modifying the part
 
 
* Equation (1), the competition equation, will be used in the competition. The volume will be measured in cubic millimeters.
 
<center><math>Competition\ Equation = [\frac{Final\ Safety\ Factor}{Final\ Volume} -\ \frac{Initial\ Safety\ Factor}{Initial\ Volume}] \times 10^4\,</math></center>
<p style="text-align:right">(1)</p>
 
==== Design Consideration ====
 
* Do not simply add a long or large block to the redesigned part
* Consider bridges, cranes, and other systems that use structural support in the redesign
* Consider how material choices will impact the safety factor
* Consider how the part can be modified to support higher loads
 
==== Parts Selection ====
 
There are seven parts to choose from for the competition (Figures 62 - 69). Click on the image of the part to download the Fusion file for that part. Areas shown in red cannot be modified in any way. Components, such as fillets, chamfers, or other extrusions, including lofts and sweeps, can be added to the part.
 
[[Image:Crane Truss Case.png|link={{filepath:CraneTrussCase.zip}}|600px|thumb|center||[[Media:CraneTrussCase.zip|Figure 62: Crane Truss Case (Click to Download)]]]]
 
[[Image:Weight Bearing Latch.png|link={{filepath:WeightBearingLatch.zip}}|600px|thumb|center||[[Media:WeightBearingLatch.zip|Figure 63: Weight Bearing Latch (Click to Download)]]]]


= What can and can not be edited =
[[Image:Wire Supported Shelf.png|link={{filepath:WireSupportedShelf.zip}}|400px|thumb|center||[[Media:WireSupportedShelf.zip|Figure 64: Wire Supported Shelf (Click to Download)]]]]
The following parts show in red what cannot be modified. The red areas cannot be cut, made longer, or thicker. However, you can add onto them such as make fillets, chamfers or other extrusions (includes lofts or sweeps).


[[File:Part_1.PNG|500px|thumb|center|Figure 4: Crane Truss Case]]
[[Image:Pipe-Like Placeholder.png|link={{filepath:PipeLikePlaceholder.zip}}|600px|thumb|center||[[Media:PipeLikePlaceholder.zip|Figure 65: Pipe-Like Placeholder (Click to Download)]]]]


[[File:Part_2.PNG|500px|thumb|center|Figure 5: Weight Bearing Latch]]
[[Image:Truss Pyramid.png|link={{filepath:TrussPyramid.zip}}|600px|thumb|center||[[Media:TrussPyramid.zip|Figure 66: Truss Pyramid (Click to Download)]]]]


[[File:Part_3.PNG|500px|thumb|center|Figure 6: Wire Supported Shelf]]
[[Image:Broken Truss Tower.png|link={{filepath:BrokenTrussTower.zip}}|600px|thumb|center||[[Media:BrokenTrussTower.zip|Figure 67: Broken Truss Tower (Click to Download)]]]]
<!--[[Image:Screwed Bracket.png|link={{filepath:ScrewedBracket.zip}}|600px|thumb|center||[[Media:ScrewedBracket.zip|Figure 68: Screwed Bracket (Click to Download)]]]]-->


[[File:Part_4.PNG|500px|thumb|center|Figure 7: Pipe-like Placeholder]]
[[Image:Poorly Constructed Bridge.png|link={{filepath:PoorlyConstructedBridge.zip}}|400px|thumb|center||[[Media:PoorlyConstructedBridge.zip|Figure 68: Poorly Constructed Bridge (Click to Download)]]]]


[[File:Part_5.PNG|500px|thumb|center|Figure 8: Weight Bearing Table Face]]
=== Procedure ===


[[File:Part_6.PNG|500px|thumb|center|Figure 9: Weight Bearing Table Face, underside]]
# Download the part to be modified as determined by the Lab TA. Extract the ZIP folder that was downloaded to obtain the F3D file.
# Open Fusion. Go to '''File → Open''' and select the downloaded part. Select the '''Design''' workspace in the top left of the window (Figure 70). [[File:Lab 4 Figure 17.PNG|600px|thumb|center|Figure 70: Workspace Options]]
# Open the '''Bodies''' in the '''Browser''' on the left hand side of the window, right click on the body of interest, and click '''Properties''' (Figure 71). [[File:Lab 4 Figure 18.PNG|185px|thumb|center|Figure 71: Properties of a Body]]
# From the '''Properties''' dialog, record the volume of the body in cubic millimeters.
# Click the workspace drop-down menu at the top left of the window and change the workspace to '''Simulation'''.
# Open the '''Static Stress''' study in the '''Browser''', and open the '''Study Materials''' tab (Figure 72). Record the material being used. [[File:Lab 4 Figure 19.PNG|204px|thumb|center|Figure 72: Study Material]]
# Determine the location the load is being applied (Figure 73). Double click the blue force arrow and record the magnitude of the force in Newtons. [[File:Lab 4 Figure 20.PNG|600px|thumb|center|Figure 73: Applied Loads]]
# In the '''Browser''', select '''Mesh (right click) → Generate Mesh''' (Figure 74). If the mesh is already generated and an error occurs, select '''OK'''. [[File:Lab 4 Figure 21.PNG|211px|thumb|center|Figure 74: Generate Mesh]]
# In the '''Browser''', right click '''Results''' and select '''Solve'''. Follow the '''Solve''' dialog until the simulation is complete. Click '''Close''' and the results should look like Figure 75.[[File:Lab 4 Figure 22.PNG|600px|thumb|center|Figure 75: Results of the Simulation]]
# Record the safety factor for the design.
# Sketch a possible solution that would add extra support against the force being applied, remembering what cannot be modified. Recall that the modified design must have a safety factor of at least 3. Have the sketch approved by a TA.
# Go back to the '''Design''' workspace in Fusion and use the tools shown to add  support to the original part (i.e. '''Extrude''' and '''Sweep''').
# Once the part has been modified, go back to the '''Simulation''' workspace.
# Change the material of the part, as it can increase the safety factor by right clicking on '''Study Materials''' in the '''Browser''' tab (Figure 76).[[File:Lab_Study_Materials_CAD.png|600px|thumb|center|Figure 76: Study Materials]]
# Click on the '''Study Materials''' (Figure 77) to open the drop down menu and change it to one of the  four metals (Aluminum, steel, copper, lead).[[File:Lab_Changing_Study_Materials_CAD.png|600px|thumb|center|Figure 77: Changing the Study Materials]]
# Run the analysis again with the modified part by selecting '''Mesh → Generate Mesh''' in the '''Browser'''.
# Solve the results and record the safety factor of the modified design. The design may become bent as the results are exaggerated in the simulation to gain a better understanding of how the part performs with an applied load.
# If the safety factor of the modified parts is less than 3, add additional supports and/or change the material of the part and run the simulation again.
# Once the required safety factor has been achieved, record the safety factor and volume of the modified part. Give the values of the safety factor and volume of the modified part to the TA to calculate the competition ranking.


[[File:Broken_Truss_Tower.PNG|500px|thumb|center|Figure 10: Broken Truss Tower]]
== Assignment ==


[[File:Screwed_in_Bracket.PNG|500px|thumb|center|Figure 11: Screwed in Bracket]]
=== Individual Lab Report ===


[[File:Poorly_constructed_bridge.PNG|500px|thumb|center|Figure 12: Poorly Constructed Bridge]]
{{Labs:Lab Report}} Please only discuss Part 3, the Fusion competition, in the lab report.


*Abstract
**Briefly summarize the lab exercise. Include the competition results
*Introduction
**Discuss the uses and advantages and disadvantages of CAD software
**Define safety factor and discuss the physical properties of materials observed in the lab
**Discuss Fusion
***Workspaces
***Tools and other components used in the lab exercise
**Discuss the competition
***Present the competition equation using Equation Editor and discuss it
***Discuss rules
***Discuss available materials
***Discuss design strategy and impact of rules, materials, and competition equation on design strategy
*Procedure
**Materials
**Describe what was done in sufficient detail so that another person could follow the description and replicate the results. Reference tools and workspaces used
*Data/Observations
**Present and discuss the first Fusion simulation. Include simulation and all data
**Present and discuss all additional simulations. Include simulations and all data
**Present and discuss competition equation. Include the calculation using Equation Editor and initial and final safety factor and initial and final volume
**Present and discuss competition results. Include all data and table
*Conclusion
**Analyze competition results
***Discuss role of safety factor, volume, materials in determining competition results 
**Discuss ways to improve the design’s performance in the competition
*Contribution statement   


= Procedure =
=== Team PowerPoint Presentation ===
== Part 1: Fusion 360 ==


# Open the predetermined part under the “Model” tab in the drop-down menu
{{Labs:Team Presentation}}
# Right-click on "bodies" from the outline on the left and find the volume of the part
## Model Components→bodies→right-click bodies→properties
# Record Volume in mm3
# Select the “Model” drop-down menu at the top left and change it to “Simulation”
# Click “Materials” in the top toolbar and record the “study material” being used
# Determine the location the force is being exerted on
# Double click the force arrow and record the force in Newtons
# Right-click "Mesh" then select Generate mesh
## If the mesh is already generated and a popup occurs, just select ok
# Right-click results and select "Solve"
# Sketch a possible solution to the broken part that would add extra support to the face where the force is being applied (At the bottom of the page are the parts with what cannot be modified). Have it approved by the TA
# Go back to the model section and use the tools showed to add the needed support to the original part
# Change the material of the part if needed, as it can increase the safety factor
# Once complete go back to the simulation tab
# Right-click "Mesh" and select "Generate mesh"
# Run results and record safety factor
## Do not be alarmed if the model is bending a lot, the results are exaggerated to gain a better understanding of how the part moves with an applied load
# If the new part does not have a factor of safety of at least 3, repeat steps 8-12
# Test the competition ratio once you have the desired safety factor
'''(Stop testing after 1 hour and move onto part 2)'''


== Part 2: Revit ==
*Why is CAD software, such as Fusion, AutoCAD, or SolidWorks, an important tool for engineers?
# After reading the prompt, sketch your solution and indicate the square footage. Have it approved by a TA
*Include the four basic CAD drawing views (top, most detailed side, front, and isometric) of the mechanical part before and after modifications (eight drawings total)
# Open Revit and select 'new project', then the 'architectural template'
*How are simulations used in engineering design?
# Go to Manage tab, select project units (or type UN), click under format for length and select “Feet and Fractional Inches”
*Explain the material selected for the redesign of the part
# Ensure the properties tab is open by right-clicking the mouse and hitting properties
*Define safety factor and discuss the physical properties of materials observed in the lab
# First create the exterior walls selecting 8” thick and 10’ high walls
*How did having a constrained volume impact the design process?
## You can choose to insert the floor here or at the end. The floor should run along the outside of the exterior walls
*How did the redesign compare with other redesigns?
# Insert the interior walls (6” thick and 10’ high) for the bathroom and any other if there are
*Did the material have an impact on the safety factor, and if so, why?
## '''NOTE: For Steps 7-9 Look at the Powerpoint guide for help needed on walls'''
# Insert doors and windows in the apartment
## Go to insert→ load families→doors/windows for a wide range of doors and windows. Doors should be 3 feet wide and 7 tall (no specifications for windows)
# Only the specified furniture/appliances from the problem specification must be present in the floor plan including the entire bathroom
## Insert Tab→ Load Family→ Furniture→ Beds/Seating/Storage/Tables
## Insert Tab→Load Family→ Plumbing→ MEP→ Fixtures→ Showers/Lavatories/water closets
## Insert Tab→Load Family→ Plumbing→ MEP→ Fixtures→ Appliances→ Kitchen Unit (insert 25x84 Kitchen Unit, it includes all of the necessary kitchen appliances)
# When loading furniture or appliances go to the structure tab then select component. On the left-hand side of the properties tab, you can select whichever one of the appliances you have downloaded using load families and drag and drop into the model
# Insert a ceiling (GWB on Mtl. Stud) on “level 1” 9’ high, once you have completed furnishing (excluding electrical equipment)
# Duplicate floor plan 1 for the electrical plan by right-clicking the first floor on properties tab then selecting “duplicate view→ duplicate” and rename the duplicate to electrical
# Insert electrical appliances into the apartment (Slide 9 shows exactly how to do this)
## Switches: Load family → Electrical→MEP→ Electrical Power→Terminals→Switch
## Lights: Load Family→ Lighting→ MEP→ Internal→
# For ceiling lights; Go onto ceiling plan level 1. Drag into the screen the lights you want to add onto the ceiling. Then, in the modify tab under "placement", select place on face. Add the ceiling lights to wherever on the ceiling you would like.
# Go back to the electrical plan and scroll down on properties tab to underlay. Change “range: Base level” to “level 1”, “range: Top-level” to “level 2” and “underlay orientation” to “look up”.
# Connect all of the visible lights and switches with a "wire" found in "Electrical" under the "Systems" tab
# Save the file as an Autodesk Revit File (.rvt) file
# Take screenshots of the project and submit the .rvt file on the EG website


= Assignment =
== Appendix == 


== Individual Lab Report ==
=== Stable Mechanical Structure and Material Choice ===
Follow the lab report guidelines laid out in the page called [[Specifications for Writing Your Lab Reports]] in the ''Technical Communication'' section of this manual. The following points should be addressed in the appropriate section of the lab report.


* Include '''both''' simulations
A stable mechanical structure design will require a high safety factor. There are several methods to improve the design of a mechanical structure.
* Why is CAD software such as Revit, Fusion 360, AutoCAD, or SolidWorks an important tool for engineers?
#Effect of failure
* Do you think there should be a universal CAD software? What are the pros and cons of this?
##Different types of design prefer different types of failure to lessen the risk of harm. Two types of failure include Brittle and Ductile failures.
* Discuss minimal design. How did having a constrained volume impact your design process?
#Material of components
* How did your redesign compare with other groups? Did the material have an impact on the safety factor and if so, why?
##Materials are usually chosen based on different factors such as physical properties and mechanical properties. Physical properties are measurable for materials, such as density, melting point, conductivity or coefficient of expansion. Mechanical properties are how a material will react with different forces applied. Some examples consist of Young’s Modulus, yield strength and ultimate tensile strength.
* Discuss the advantages and disadvantages of your own design
#Type of loads
* Why are smaller apartments such as the ones created in this lab becoming more desirable?
##A design that experiences dynamics or changing loading will require a higher safety factor than a design with static loading.
* How can you minimize the amount of electricity used in an apartment through architectural design?
#Degree of accuracy in forces
##A design that expects more consistent forces applied to it will be considered a good stable  mechanical structure that will require a lower safety factor. A design that expects unpredictable forces will require a higher safety factor.


{{Lab notes}}
Material choices can affect the design of the stable mechanical structure. As stated before materials are chosen based on different factors such as physical properties and mechanical properties. Some common materials in design are separated into different categories: metals, polymer, ceramic, and composite materials. There are advantages and disadvantages for each category of materials. Metals are good conductors of electricity and heat but bad at insulating. They have a high tensile strength which means that they are strong and good at bearing loads. Polymers are good insulators and lightweight, but they are bad at conducting electricity and heat. They are also ductile which means they have low tensile strength. Ceramics are good for high temperature applications and are good insulating materials, but they are brittle and more difficult to manufacture with than the others materials. Composites materials have other properties from other materials but they are even more difficult to manufacture with than ceramics.


== Team PowerPoint Presentation ==
The materials used in this lab are aluminum, copper, lead, and steel which are  metals. Aluminum is one of the most abundant metals on earth and less dense than steel. Since aluminum is less dense, it would be less stable than steel for a  design. Copper has very high ultimate tensile strength compared to its yield strength. This means that it has a more ductile behavior than steel. Lead is more flexible than other materials but is unable to support loads as well as the other materials. Steel has the highest ultimate tensile strength which means it can withstand the most stress before failing, but steel is not malleable.


Follow the presentation guidelines laid out in the page called
== References ==
[[EG1003 Lab Presentation Format]] in the <i>Introduction to Technical Presentations</i>
Omaia et al. 2024. “Interactive rapid prototyping combining 3D Printing and Augmented Reality.” Accessed 24 June 2024 from https://journals-sol.sbc.org.br/index.php/jis/article/view/3534/2419
section of this manual. When you are preparing your presentation, consider the following
points:


<ul>
Berselli et al. 2020. “Project-based learning of advanced CAD/CAE tools in engineering education.” Accessed 22 December 2023 from https://doi.org/10.1007/s12008-020-00687-4
<li>Why is CAD software such as Revit, Fusion 360, AutoCAD, or SolidWorks an important tool for engineers?</li>
<li> Include the 4 basic CAD drawing views (top side, front, and isometric) of the apartment </li>
<li>Why are smaller apartments such as the ones created in this lab becoming more desirable?</li>
<li>How can you minimize the amount of electricity used in an apartment through architectural design?</li>
<li> How is simulation used in engineering design? </li>
<li> Explain why you chose the material you did for your redesign of the part </li>
<li>Discuss minimal design. How did having a constrained volume impact your design process?</li>
<li> Define factory of safety </li>
<li> Include the 4 basic CAD drawing views (top side, front, and isometric) of:</li>
** The mechanical part before modifications
** The mechanical part after modifications
<li> How did your redesign compare with other groups, did material have an impact on the safety factor and if so why?</li>
<li> Discuss advantages and disadvantages of own design
</ul>


[[Main_Page | Return to Table of Contents]]'''
Musto, 2012. “The Safety Factor: Case Studies in Engineering Judgment.” Accessed 22 December 2023 from https://doi.org/10.7227/IJMEE.38.4.

Latest revision as of 18:29, 4 November 2024


Please review the CAD Guide presentation that explains the fundamentals of CAD software prior to performing this lab. The presentation is listed underneath the title Lab 2 on the EG1004 Lab Manual.

Objective

The objective of this lab is to use Autodesk Fusion to modify a three-dimensional structure to increase its minimum safety factor while minimizing any increase in volume. The structures will be evaluated in competition using a competition equation that depends on the change in the structure’s safety factors and volumes.

Overview

Computer-Aided Design

Computer-aided design (CAD) uses computer software to create, modify, or analyze the designs of 3D products (Omaia et al., 2024). Across engineering industries, CAD software allows engineers to create dimensioned, scaled drawings that allow them to explore and refine ideas safely and cost effectively (Berselli et al., 2020). Autodesk Fusion, AutoCAD, Revit, Dassault Systèmes, SolidWorks, and Sketchup Free are examples of CAD software. This exercise will use Autodesk Fusion to explore the use of CAD software to evaluate and improve the safety of a design.

Design Considerations

The safety of a structure is often defined by a metric called the safety factor (Musto, 2012). The safety factor is defined as the ratio of how much stronger a material is than the expected load. It is the measure of the load a material can sustain before permanent deformation or fracture. A common, acceptable safety factor is at least 3. Any value below that will likely lead to structural failure.

Every design decision made by an engineering team can impact the safety factor of a structure. This begins with the choice of material used for the project. The Young’s modulus, or modulus of elasticity, of a material is the measure of its tendency to deform when a force is applied in the axial direction. The yield strength of a material is the point at which the material begins to deform plastically, and the shape of the material is permanently altered. The Ultimate Tensile Strength (UTS) of a material is the maximum stress that the material can withstand before structurally failing, which usually involves bending permanently or breaking (Table 1).


Table 1: Allowed Materials and their Properties
Material Young's Modulus (GPa) Yield Strength (MPa) Ultimate Tensile Strength (MPa)
Aluminum (Al) 69 275 310
Steel 200 207 345
Copper (Cu) 118 33 210
Lead (Pb) 14 9 18

Autodesk Fusion

In this lab, Autodesk Fusion will be used to modify a part and evaluate its safety factor. Autodesk Fusion is a cloud-based CAD software; it uses remote servers hosted via the Internet to process, store, compute, create, and analyze 3D models of structures.

The two workspaces in Fusion that will be used in this experiment are Design and Simulation (Figure 1). The Design workspace creates mechanical designs that contain information about geometric constraints, and the Simulation workspace simulates applied loads on a design to observe the design's performance under those loads.

Figure 1: Fusion Workspaces

There are two tabs in the Design workspace: Create and Modify. The Create and Modify tabs contain the functions needed for sketching and building a 3D model. They create and modify sketches when in Sketch mode (Figure 2).

Figure 2: Create and Modify Tabs in Sketch Mode

A Sketch creates the 2D shapes that are the bases for all 3D models. When first sketching the shapes, they do not have to have accurate dimensions or scale. Using the Sketch Dimension tool and the Constraints functions, the base shape and 3D model can be edited without starting over (Figure 3).

Figure 3: Before (Left) and After (Right) of Sketch Using the Sketch Dimension Tool

Once a sketch is complete, the Create and Modify tabs are also used to generate the 3D model (Figure 4).

Figure 4: Create and Modify Tabs in Model Mode

The Extrude, Sweep, and Loft tools are used to give direction and depth to the 3D model. Extrude projects the initial sketch outward to create a model. The Sweep tool creates a 3D model of a predetermined surface (profile) along a specific path. The Loft tool creates a 3D extrusion to connect two profiles of any shape (Figure 5). The Sweep and Loft tools are particularly useful for creating extrusions at an angle.

Figure 5: Examples of Extrude (Left), Sweep (Middle), and Loft (Right)

The Loft/Sweep Tutorial video demonstrates how to use these tools. Table 1 shows common Fusion shortcuts.

Table 2: Common Fusion Shortcuts
Command Windows Key Combination Mac Key Combination
Pan
Hold Middle Mouse Button
Hold Middle Mouse Button
Zoom
Roll Middle Mouse Button
Roll Middle Mouse Button
Orbit
Hold Shift + Middle Mouse Button
Hold Shift + Middle Button
Undo
Ctrl + Z
Command + Z
Redo
Ctrl + Y
Command + Z + Shift
Copy
Ctrl + C
Command + C
Paste
Ctrl + V
Command + V
Cut
Ctrl + X
Command + X
Extrude
E
E
Move
M
M

The Timeline function located at the bottom of the screen contains a record of the design history that can be modified or manipulated. The controls located to the left can be used to visit previous actions (Figure 6). The middle button will play the design history as an animation. The gray slider on the timeline can be dragged to different areas to show the design at a given stage. Actions can also be removed from the timeline and the design will automatically update itself if errors do not occur later in the timeline.

Figure 6: Timeline Function

The Simulation workspace can run simulations to test how a design will perform under real-world conditions. A Static Stress simulation, for example, analyzes the deformation, stress, and safety factor of a design from structural loads and constraints. The assumptions used in the simulationare based on a linear response to stress when the load being applied is known and constant. The results determine if a design will deform excessively or fail (break) from the loads applied. To run the tests, loads and constraints are placed on the design.

Constraints consist of fixed, pinned, and frictionless support options that prevent motion in specific directions. Fixed constraints prevent all motion and displacement of a part (Figure 7). This would mimic a screw holding a part in place. A pinned support prevents movement in radial, axial, and/or tangential directions, but allows a part to rotate. Frictionless constraints prevent movement normal to the surface. This mimics a wall or floor to prevent motion perpendicular to the surface.

Figure 7: Example of Fixed Constraints

A load is the force being applied to the design (Figure 8). The force is characterized by the direction, the point of application, and the magnitude of the force being applied.

Figure 8: Example of Loads

A Mesh is a boundary along the design made up of polygons that determine the precision of the analysis test (Figure 9). The analysis is run at every vertex. More polygons in the mesh would deliver more precise results with longer simulation time. When a part is altered, it is essential to regenerate the mesh.

Figure 9: Example of a Mesh

Materials and Equipment

  • A lab PC
  • Autodesk Fusion

Procedure

Part 1. Setting up the File

  1. Launch AutoDesk Fusion, click Create Account, and fill in the information. Important: Make sure to use an NYU email (Figure 10).
Figure 10: Fusion New File Options

Part 2. Learning Exercise

The following activity will be performed prior to the CAD competition to allow students to familiarize themselves with the software.

  1. Download the following Screwed Bracket from the manual.
  2. Change the workspace from Simulation to Design in the top-leftmost drop down. Set the units of the drawing to millimeters. The Units setting is found in the Browser on the left side of the window under Document Settings.
  3. Select one of the inner faces and start a 2D Sketch by clicking Create Sketch (Figure 11).
    Figure 11: Creating a 2D Sketch on a Face
  4. Create a Center Diameter Circle with a diameter of 14 mm by clicking on the center of the existing circular cut. Click Finish Sketch (Figure 12).
    Figure 12: Sketching a Circle
  5. Go to Create → Extrude, which will be used to create a cylinder. Select both contours (Figure 13).
    Figure 13: Creating a Cylinder
  6. Change the Extent Type to To Object. Select the opposite inner face (Figure 14). Make sure the operation is set to Join.
    Figure 14: Extruding Circle to Face
  7. Select the outer base face as show in the image from Step 8. Select the 2-Point Rectangle from the Sketch section of the toolbar (Figure 15).
    Figure 15: Point Rectangle
  8. Draw a 10 mm x 6 mm rectangle starting by clicking once at one of the vertices of the flat border (Figure 16) to place one point of the rectangle and click one more time to place the second point of the rectangle. The lengths can be typed in before placing the second point of the rectangle (switching which value is changed is done using the Tab key). Press Finish Sketch.
    Figure 16: Dimensions of Rectangle
  9. Select the perpendicular face nearest to the rectangle (drawn in the previous step) and start a 2D Sketch. Draw a 10 mm x 4 mm rectangle 8 mm from the base. The horizontal side of the rectangle must be parallel to the previous sketch (Figure 17). To accurately measure the 8 mm from the base, select the Sketch Dimension tool. Then select the bottom horizontal edge of the rectangle and the edge shown in the purple image below, then move the cursor to the right, click, and the dimension should show up. Then edit the measurement to 8 mm.
    Figure 17: Dimensions of Second Rectangle
  10. Next, align the new rectangle with the one previously drawn. Use Constraints → Collinear, and select the left line of the lower rectangle then the left side of the new rectangle as shown in Figure 18. Then select Finish Sketch.
    Figure 18: Collinear Constraints
  11. Go to Create → Loft. Select the previous two rectangles as Profiles. Make sure to scroll down and change Operation to New Body, or Step 12 will not work properly. (Figure 19).
    Figure 19: Lofting a New Body
  12. Click on Construct → Midplane and select both of the inner walls (Figure 20).
    Figure 20: Midplane
  13. Go to Create → Mirror. Select the Loft as the Object and the Plane as the Mirror Plane (Figure 21).
    Figure 21: Mirroring Steps
  14. This part should look like Figure 22.
    Figure 22: Mirrored Loft
  15. Select the central base and start a 2D Sketch. Draw two 5 mm Center Diameter Circles with the origin on the center line 8 mm from the edge (Figure 23). Finish the Sketch.
    Figure 23: Dimensions Circles
  16. Start a 2D Sketch on the midplane. Click on Create → Arc → 3 Point Arc. Place the first and the second points in the centers of each of the circles created in the previous step, as shown in Figures 24-25.
    Figure 24: Creating Arc
    Figure 25: Creating Arc
  17. Place the third point so that your arc looks somewhat similar to the figure below. You may need to adjust your view so it is oriented as shown in the figure below. Using Create → Sketch Dimension select one of the end points and the third arc point, drag the dimension straight up, as shown in Figure 26 and set it to be 9 mm. If the arc endpoints are shifted, use Constraint → Coincident on each arc endpoint and the center of their respective circles. Click Finish Sketch.
    Figure 26: Creating Arc
  18. Go to Create → Sweep. Select the two circles created in the previous step as Profiles and select the Arc as the Path. Go to Operation and choose New Body (Figure 27).
    Figure 27: Creating Sweep
  19. It should look like Figure 28. Save the design.
    Figure 28: Finished Loft
  20. Create a New Design and make a 2D Sketch by selecting any plane and create a rectangle 5 mm x 26 mm, as seen in Figure 29.
    Figure 29: Rectangle Sketch
  21. Extrude the rectangle by 1 mm (Figure 30).
    Figure 30: Extruding Rectangle
  22. A vector graphics file will be used in the DXF format provided by NYU. In the future, a logo can be designed using the Sketch tool. Download the Tandon Logo DXF File (this logo was converted from the file provided on NYU's identity page).
  23. The downloaded ZIP folder must be extracted. Select Insert DXF under the Insert section of the toolbar (Figure 31).
    Figure 31: Insert DXF Tool
  24. The Insert DXF information dialog will appear on the right side of the window. For the Plane/Sketch, select the top surface (Figure 32).
    Figure 32: Selected Top Surface
  25. Click the folder icon next to the Select DXF file to upload the Tandon Logo DXF File. The logo should appear (figure 33).
    Figure 33: Imported DXF Logo
  26. Move the logo away from the origin by dragging it with your mouse (Figure 34). Alternatively, highlight the entire logo, and use the Modify → Move/Copy tool to move it.
    Figure 34: Relocated DXF Logo
  27. If the Tandon Logo imports incorrectly, as shown in Figure 35, follow Steps 28-29. Otherwise, skip to Step 30.
    Figure 35: Incorrect Tandon Logo Orientation
  28. Select the Modify → Move/Copy tool. For Move Object, select sketch objects. For Selection, click and drag to select the entire Tandon logo. For Move Type, select rotate. For Axis, select the top horizontal line and set the angle to 180°, as seen in Figure 36.
    Figure 36: Flip About the Horizontal Line
  29. Repeat Step 21, but for Axis, select the right vertical line and set the angle to be 180° (Figure 37).
    Figure 37: Flip About the Vertical Line
  30. The imported Tandon logo is shown in Figure 38.
    Figure 38: Imported Tandon Logo
  31. The vertical bar and Tandon School of Engineering portions of the logo are not needed. Select the bar and text to the right by clicking and dragging (Figure 39). Delete this portion with the Delete key on the keyboard (not Backspace).
    Figure 39: Tandon to Delete
  32. The logo must be scaled to fit the part. A base point must be selected to scale the sketch. The midpoint of the line on the right side of the box around the torch will be used as the base point, so a point must be placed there first.
  33. Before placing a point, the sketch must be in editing mode. A sketch is in editing mode when the background turns into guidelines, and Finish Sketch appears at the top right of the window. Edit the logo by selecting Browser → Sketches and double-clicking on the tandon_logo_white sketch (Figure 40).
    Figure 40: Sketches in Browser
  34. Select the Create → Point tool. Place a point at the midpoint of the right side of the box around the torch (Figure 41). This is the base point.
    Figure 41: Midpoint on Box
  35. Right click the bottom left corner point of the box around the torch, When selected on the correct point, select Delete Coincident (Figure 42). You may also need to repeat this for the lines connected to the point.
    Figure 42: Delete Coincident
  36. Select the Modify → Sketch Scale tool. The Sketch Scale information dialog will appear on the right hand side of the window. For the Entities, circle the entire logo by clicking and dragging. Do not select the midpoint created in Step 34. If the midpoint was selected, clicking on the point again will unselect it.
  37. Switch to Point and select the midpoint created in Step 34 (Figure 43).
    Figure 43: Select Midpoint
  38. In the Sketch Scale window, a third option will appear as Scale Factor. enter a scaling factor of 4.5 and click OK (Figure 44).
    Figure 44: Scale Factor
  39. Drag and re-locate the logo so it fits cohesive with the sizing. It should look like the logo in Figure 45.
    Figure 45: Final Logo
  40. Create a 2D sketch on one of the main faces where the logo was inserted. Go to Create → Text. Make the box smaller than the face, as shown in Figure 46. Type in the designer's name and format it so it is Bold and will be visible and cohesive with the size of the part. Some recommended setups are shown in Figure 46.
    Figure 46: Text Tool
  41. After writing, finish the sketch. It should look like Figure 47.
    Figure 47: Recommended Dimension for Text
  42. The design must be cut into the base. To do this, the Extrude tool will be used.
  43. To cut the design, select Create → Extrude on the toolbar. The Extrude information dialog will appear on the right hand side of the window. Select the design profile, which is the area around the torch and each of the letters.
  44. In the Extrude window, scroll down to Operation, and select Cut. Then set the Distance to -0.2 mm (Figure 48). Click OK. Save the design and return to the Bracket.
    Figure 48: Engraved Part
  45. The final model is shown in Figure 49.
    Figure 49: Final Model
  46. An assembly between the Plate and Bracket must be made. The Bracket file will be used. In this case, the engraved Plate will be the one floating, which means that it will be the one moving to arrange the pieces in the desired order. In the Bracket file, click on Show Data Panel in the top left corner, as shown in Figure 50.
    Figure 50: Show Data Panel
  47. Once opened, the preview of the Plate should be visible (Figure 51).
    Figure 51: Preview
  48. Click and drag the Plate from the left to the right, where the main screen with the part is. Drop the Plate here. It should look like Figure 52. Press OK.
    Figure 52: Imported Plate
  49. Both parts must be listed as components to create Arrangements between them. The Plate was imported as a component already, now the main part is the only one missing. To do this, right click on Bodies and select Create components from Bodies (Figure 53). This will create four different components.
    Figure 53: Convert to Bodies
  50. Click on Modify → Move/Copy and switch from Bodies to Components, as seen in Figure 54.
    Figure 54: Option Selection
  51. Select the midpoint of the Plate (Figure 55).
    Figure 55: Selecting for Orientation
  52. Modify the Plate so it matches the orientation on Figure 56 by clicking the round circles and rotating it. Press OK.
    Figure 56: Orientation
  53. The position of the Plate needs to be exact. Go to Modify → Align (Figure 57) and click the back of the engraved Plate and the lower wall of the part.
    Figure 57: Align Feature
  54. The order matters as it will move one part to the other. If the part is oriented incorrectly, click on Flip and then OK. It should look like Figure 58.
    Figure 58: Correct Direction
  55. Use the Align feature again and press the left border of the Plate and the inner border of the left wall of the part, as shown in Figure 59.
    Figure 59: Border Alignment
  56. Do the same with the bottom border of both parts, as shown in Figure 60.
    Figure 60: Border Alignment
  57. If the plate is oriented incorrectly, use the Flip option to re-orient the Plate.
  58. At the end, it should look like Figure 61.
    Figure 61: End Result

Part 3. Fusion Competition

This portion of the lab is a competition that requires teams to redesign an unsafe part to have a minimum safety factor. The competition rules are listed below. The winner of the competition will receive extra credit as detailed in the Grading Policy.

Competition Rules

  • The redesigned part must have a safety factor of at least 3
  • The redesigned part must not have more than double the volume of the original part
  • The applied forces and fixed constraints cannot be altered
  • The thickness of the base and the proportions of the original part cannot be altered
  • The supports can be altered if and only if they do not take away from or add to the base of the part
  • Only aluminum, steel, copper, or lead may be used when modifying the part


  • Equation (1), the competition equation, will be used in the competition. The volume will be measured in cubic millimeters.

(1)

Design Consideration

  • Do not simply add a long or large block to the redesigned part
  • Consider bridges, cranes, and other systems that use structural support in the redesign
  • Consider how material choices will impact the safety factor
  • Consider how the part can be modified to support higher loads

Parts Selection

There are seven parts to choose from for the competition (Figures 62 - 69). Click on the image of the part to download the Fusion file for that part. Areas shown in red cannot be modified in any way. Components, such as fillets, chamfers, or other extrusions, including lofts and sweeps, can be added to the part.

Procedure

  1. Download the part to be modified as determined by the Lab TA. Extract the ZIP folder that was downloaded to obtain the F3D file.
  2. Open Fusion. Go to File → Open and select the downloaded part. Select the Design workspace in the top left of the window (Figure 70).
    Figure 70: Workspace Options
  3. Open the Bodies in the Browser on the left hand side of the window, right click on the body of interest, and click Properties (Figure 71).
    Figure 71: Properties of a Body
  4. From the Properties dialog, record the volume of the body in cubic millimeters.
  5. Click the workspace drop-down menu at the top left of the window and change the workspace to Simulation.
  6. Open the Static Stress study in the Browser, and open the Study Materials tab (Figure 72). Record the material being used.
    Figure 72: Study Material
  7. Determine the location the load is being applied (Figure 73). Double click the blue force arrow and record the magnitude of the force in Newtons.
    Figure 73: Applied Loads
  8. In the Browser, select Mesh (right click) → Generate Mesh (Figure 74). If the mesh is already generated and an error occurs, select OK.
    Figure 74: Generate Mesh
  9. In the Browser, right click Results and select Solve. Follow the Solve dialog until the simulation is complete. Click Close and the results should look like Figure 75.
    Figure 75: Results of the Simulation
  10. Record the safety factor for the design.
  11. Sketch a possible solution that would add extra support against the force being applied, remembering what cannot be modified. Recall that the modified design must have a safety factor of at least 3. Have the sketch approved by a TA.
  12. Go back to the Design workspace in Fusion and use the tools shown to add support to the original part (i.e. Extrude and Sweep).
  13. Once the part has been modified, go back to the Simulation workspace.
  14. Change the material of the part, as it can increase the safety factor by right clicking on Study Materials in the Browser tab (Figure 76).
    Figure 76: Study Materials
  15. Click on the Study Materials (Figure 77) to open the drop down menu and change it to one of the four metals (Aluminum, steel, copper, lead).
    Figure 77: Changing the Study Materials
  16. Run the analysis again with the modified part by selecting Mesh → Generate Mesh in the Browser.
  17. Solve the results and record the safety factor of the modified design. The design may become bent as the results are exaggerated in the simulation to gain a better understanding of how the part performs with an applied load.
  18. If the safety factor of the modified parts is less than 3, add additional supports and/or change the material of the part and run the simulation again.
  19. Once the required safety factor has been achieved, record the safety factor and volume of the modified part. Give the values of the safety factor and volume of the modified part to the TA to calculate the competition ranking.

Assignment

Individual Lab Report

Follow the lab report guidelines laid out in the EG1004 Writing Style Guide in the Technical Writing section of the manual. Use the outline below to write this report. Please only discuss Part 3, the Fusion competition, in the lab report.

  • Abstract
    • Briefly summarize the lab exercise. Include the competition results
  • Introduction
    • Discuss the uses and advantages and disadvantages of CAD software
    • Define safety factor and discuss the physical properties of materials observed in the lab
    • Discuss Fusion
      • Workspaces
      • Tools and other components used in the lab exercise
    • Discuss the competition
      • Present the competition equation using Equation Editor and discuss it
      • Discuss rules
      • Discuss available materials
      • Discuss design strategy and impact of rules, materials, and competition equation on design strategy
  • Procedure
    • Materials
    • Describe what was done in sufficient detail so that another person could follow the description and replicate the results. Reference tools and workspaces used
  • Data/Observations
    • Present and discuss the first Fusion simulation. Include simulation and all data
    • Present and discuss all additional simulations. Include simulations and all data
    • Present and discuss competition equation. Include the calculation using Equation Editor and initial and final safety factor and initial and final volume
    • Present and discuss competition results. Include all data and table
  • Conclusion
    • Analyze competition results
      • Discuss role of safety factor, volume, materials in determining competition results
    • Discuss ways to improve the design’s performance in the competition
  • Contribution statement

Team PowerPoint Presentation

Follow the presentation guidelines laid out in the EG1004 Lab Presentation Format in the Technical Presentations section of the manual. When preparing the presentation, consider the following points.

  • Why is CAD software, such as Fusion, AutoCAD, or SolidWorks, an important tool for engineers?
  • Include the four basic CAD drawing views (top, most detailed side, front, and isometric) of the mechanical part before and after modifications (eight drawings total)
  • How are simulations used in engineering design?
  • Explain the material selected for the redesign of the part
  • Define safety factor and discuss the physical properties of materials observed in the lab
  • How did having a constrained volume impact the design process?
  • How did the redesign compare with other redesigns?
  • Did the material have an impact on the safety factor, and if so, why?

Appendix

Stable Mechanical Structure and Material Choice

A stable mechanical structure design will require a high safety factor. There are several methods to improve the design of a mechanical structure.

  1. Effect of failure
    1. Different types of design prefer different types of failure to lessen the risk of harm. Two types of failure include Brittle and Ductile failures.
  2. Material of components
    1. Materials are usually chosen based on different factors such as physical properties and mechanical properties. Physical properties are measurable for materials, such as density, melting point, conductivity or coefficient of expansion. Mechanical properties are how a material will react with different forces applied. Some examples consist of Young’s Modulus, yield strength and ultimate tensile strength.
  3. Type of loads
    1. A design that experiences dynamics or changing loading will require a higher safety factor than a design with static loading.
  4. Degree of accuracy in forces
    1. A design that expects more consistent forces applied to it will be considered a good stable mechanical structure that will require a lower safety factor. A design that expects unpredictable forces will require a higher safety factor.

Material choices can affect the design of the stable mechanical structure. As stated before materials are chosen based on different factors such as physical properties and mechanical properties. Some common materials in design are separated into different categories: metals, polymer, ceramic, and composite materials. There are advantages and disadvantages for each category of materials. Metals are good conductors of electricity and heat but bad at insulating. They have a high tensile strength which means that they are strong and good at bearing loads. Polymers are good insulators and lightweight, but they are bad at conducting electricity and heat. They are also ductile which means they have low tensile strength. Ceramics are good for high temperature applications and are good insulating materials, but they are brittle and more difficult to manufacture with than the others materials. Composites materials have other properties from other materials but they are even more difficult to manufacture with than ceramics.

The materials used in this lab are aluminum, copper, lead, and steel which are metals. Aluminum is one of the most abundant metals on earth and less dense than steel. Since aluminum is less dense, it would be less stable than steel for a design. Copper has very high ultimate tensile strength compared to its yield strength. This means that it has a more ductile behavior than steel. Lead is more flexible than other materials but is unable to support loads as well as the other materials. Steel has the highest ultimate tensile strength which means it can withstand the most stress before failing, but steel is not malleable.

References

Omaia et al. 2024. “Interactive rapid prototyping combining 3D Printing and Augmented Reality.” Accessed 24 June 2024 from https://journals-sol.sbc.org.br/index.php/jis/article/view/3534/2419

Berselli et al. 2020. “Project-based learning of advanced CAD/CAE tools in engineering education.” Accessed 22 December 2023 from https://doi.org/10.1007/s12008-020-00687-4

Musto, 2012. “The Safety Factor: Case Studies in Engineering Judgment.” Accessed 22 December 2023 from https://doi.org/10.7227/IJMEE.38.4.