Design Failure: Cause & Effect

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Summary

This session is intended to introduce the concept of minimal design and its effects. It will provide a challenging opportunity for you to compete in creatively designing a box that will encase a fragile object (an egg), and protect the object from breaking, when dropped from a height. Your design will be dropped twice from the fourth floor, once by itself and again with an added weight. The challenge here is in minimal design (you are required to use only the materials provided, and should make the design as simple as possible). Most box designs will fail. This laboratory session gives you an opportunity to learn from failure, and to discuss and explain why and how the failure occurred. The best design will be chosen from those that do not fail, and will be the most minimal design. The winners of the design competition receive an "A" and are exempt from writing the report. This group, however, must prepare and present a description of their winning design at their next recitation meeting.

Objectives

  • Prepare a TEAM DESIGN for a light-weight container to protect a fragile object such as a raw egg from breaking when dropped from a specified height.
  • Build the container as a TEAM from materials provided.
  • TEST the container following the provided guidelines.
  • KEEP careful notes on the design rationale, the construction of the container, and the results of the test, and prepare a written report as discussed below.

Preparation

Read this document carefully before beginning work.

Materials

  • A cardboard box [to be assembled].
  • Elastic bands, adhesive tape, stapler, foam pieces, poly-fil.
  • An egg wrapped in plastic wrap.

Problem Statement

As a team, design and build a container for the egg. At the time announced by your instructor bring the egg in the container to the designated location for testing. Prepare a written report for your team.

Procedure

  1. EXAMINE the materials made available.
    • IDENTIFY the materials to be used in construction.
    • DESCRIBE in your laboratory notebook why you think each material has been included in your kit.
  2. Plan your design of the box and describe how your team will build it using the materials made available. Keep track of the cost of your design. See Appendix A for price list. RECORD notes and sketches in your laboratory notebook. The instructor will initial your notebook before you begin construction.
  3. Construct the box as a team. you are expected to design the box to perform its function with as little material as possible. This is the challenge in the design. Record your thinking process in your laboratory notebook as you construct your box.
  4. One partner will be directed to a balcony from which to drop the box (labeled with your name) 35 feet onto a concrete floor. After the box is dropped, the other partner will retrieve it and return it to the balcony.
  5. Return the box to the balcony for the second drop. Here, books will be attached to the box to increase the force acting on it at impact.
  6. TAKE the box back tot he lab and document in your notebook what has happened to the box and egg.

Report

  • Independent written report.
  • The group whose egg survives and has the least materials wins the competition and is exempt from writing a report (receives an A). Whit group, however, must prepare and present a description of their winning design at their next recitation.
  • Use the WORD PROCESSOR in the lab to prepare written documentation of your design, and the analysis of the design, based on the testing. Include in your report a sketch of your design. DISCUSS each of the items listed below:
    1. Why doe the design fail when the box falls from a given height?
    2. Does the height matter? Would you expect different results if a different height were used? Explain.
    3. What is the function of the different materials given to you to use in construction? Explain the role of each.
    4. Does the choice of materials matter? Explain. Can you think of better materials to use? Discuss.
    5. Explain why minimal design was emphasized?

Recitation Discussion Topics

  • Discussion/Best Design Presentation.
  • Discuss reasons for choice of materials used.
  • Why was minimal design emphasized?
  • Discuss the strategy employed by the winning group.

Appendix A

Price List for Materials
Bubble Wrap $0.50/ft2
Cotton Wrap $0.60/ft2
Tape $0.10/ft
Rubber Bands (Small) $0.01 each
Rubber Bands (Large) $0.02 each
Styrofoam Pieces $0.05/6
Staples $0.01/10
Saran Wrap $0.02/ft2
Plastic Zip-Loc Bags $0.15 each

Reminder

If more than one egg survives, the winner of this competition will chosen based on minimal design. (i.e. The team with the least expensive design.)