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. Key specifications: • 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. Design objective The 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. Report The design will be done in U.S. Customary Units.
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 a dual swing arm lamp Design objective The 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. Report The design will be done in U.S. Customary Units.
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
Activities ·Identify & review assumptions ·Do analysis & make design decisions ·Complete design of components ·Draft assembly drawing; sketch detail drawings as possible ·Complete a peer review of another team’s report draft ·Revise report ·Finalize report
References Course 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 • Project Drawings, Parts List and Bill of Materials. (15%) • Methods. (15%) • Assumptions/Warnings. (5%) • References.(5%) • Data (Materials Data Table (5%), Loads Data (5%), Other Data(5%)) • Calculations. (30%) • Oral presentation (15%)