MAE 243

MECHANICS OF MATERIALS

COMPUTER BASED DESIGN PROJECTS

Dr. Konstantinos A. Sierros

General info

• Form working groups of 4 students each

• Choose a proposed computer based design project

• The project will consist of a report showing all calculations, designs, materials used, total cost etc

• Each group will also give a 10 minutes presentation

• Each group member is expected to contribute in the team effort (members who will not contribute will get 0 points)

Design a lightweight deck chair having simple, but elegant lines

• Dimensions and strength to accommodate the 95 percentile range of the U.S. male population as determined by standard anthropometric data. • Shaped ergonomically for comfort. • Components will ship disassembled and assemble easily using pliers and a screwdriver by a customer with little mechanical inclination. • Design for mild impact• As a precaution against material yielding, set the factor of safety (FS) to 1.3. • Finish base rail to prevent marring floors and slipping.

Design a lightweight deck chair having simple, but elegant lines. Key specifications:

Design objectiveThe design objectives are light weight and minimum cost in that order. Hence a figure of merit equal to the weight of the chair in pounds multiplied by the cost in dollars is to be reported. Costs are to be determined using nominal retail prices.

Special concerns•Consider that chairs may be subjected to unorthodox treatment. For instance, it would be wise to design the arm of the chair to support somewhat more force than that applied when leaning on the arms to sit or rise. •The chair should be well balanced. In particular, it should be difficult to tip it over backwards from a sitting position.

ReportThe design will be done in U.S. Customary Units.

Design a lightweight deck chair having simple, but elegant lines.

Design a dual swing arm lamp

Design a dual swing arm lamp. Key specifications:

• Dimensions to accommodate those of a typical American sofa. Height to be 40 in minimum. • Load to accommodate the 50th percentile range for weight of U.S. children who have just turned three years old . • All internal wiring shall be concealed within the lamp . • Safety factors are 1.5 for material yielding and 2.2 for buckling. • Each swing arm will be 4.5 in long minimum. • Materials to have an attractive appearance with surface finish

Design objectiveThe design objective is low cost, but not at a loss in elegance or appearance and finish. Costs are to be estimated using nominal retail prices.

Special concerns•Consider that the lamp may be carried by either arm or the post. •Weakness of the arm-to-hinge joints. •Safety in general is a major concern. The lamp should be stable under normal use.

ReportThe design will be done in U.S. Customary Units.

Design a dual swing arm lamp

Activities

Conduct a product comparison

Develop a general design concept and research key dimensions & data

Research and select materials

Research and set primary load(s)

Set key dimensions and identify those to be calculated

Identify types of analysis for each component.

Print Report Format and distribute responsibilities to team members

Set material properties/allowables

Model & analyze each component

Identify & review assumptions

Do analysis & make design decisions

Complete design of components

Draft assembly drawing; sketch detail drawings as possible

Activities

Complete a peer review of another team’s report draft

Revise report

Finalize report

ReferencesCourse textbook

Hibbeler, R.C. (1997) Mechanics of Materials, 3rd ed., Prentice Hall, Englewood Cliffs.

Roark, Raymond J. and W. C. Young (1975) Formulas for Stress and Strain, McGraw-Hill Book Co., New York, Table 37. Formulas of stress concentration for elastic stress.

Salvendy, Gavriel (1997) Handbook of Human Factors and Ergonomics, John Wiley & Sons, Inc., New York.

Pheasant, Stephen (1996) Bodyspace: anthropometry, ergonomics and the design of work, 2nd ed., Taylor & Francis, London.

Report

1.Project Drawings, Parts List and Bill of Materials. (15%) 2.Methods. (15%) 3.Assumptions/Warnings. (5%) 4.References.(5%) 5.Data (Materials Data Table (5%), Loads Data (5%), Other Data(5%)) 6.Calculations. (30%) 7. Oral presentation (15%)