2. Ken YoussefiSJSU, ME dept. 1 Material Selection Function MaterialShape Process Material selection and process cannot be separated from the shape and the function of the product, two way interaction. Function dictates the choice of material and shape. Process interacts with shape. Process is influenced by material Shape restricts the choice of material and process.

3. Ken YoussefiSJSU, ME dept. 2 Engineering Materials Materials Metals Plastics Steel Stainless steel Die & tool steel Cast iron FerrousNon-ferrous Aluminum Copper Zinc Titanium Tungsten Thermoplastics Acrylic Nylon ABS Polyethylene Polycarbonate PVC Thermosets Phenolic Polymide Epoxies Polyester Elastomers Rubber Polyurethane Silicone

4. Ken YoussefiSJSU, ME dept. 3 Engineering Materials Materials Metals Plastics Ceramics Glass Carbides Nitrides Graphite Diamond Glasses Glass ceramics Composites Reinforced plastics Metal-Matrix Ceramic-Matrix Laminates

5. Ken YoussefiSJSU, ME dept. 4 Most Commonly Used Materials The following 25 materials are the most commonly used materials in the design of mechanical products; in themselves they represent the broad range of other materials. Steel and Cast Iron 1.1020 (plain carbon steel, hot-rolled or cold-drawn) 2.1040 (plain carbon steel, hot-rolled or cold-drawn) 3.4140 (heat-treated alloy steel, chromium-molybdenum) 4.4340 (heat-treated alloy steel, nickel-chromium-molybdenum) 5.S30400 (stainless steel) 6.S316 (stainless steel) 7.O1 (tool steel) 8.ASTM20-60 (gray cast iron)

6. Ken YoussefiSJSU, ME dept. 5 Most Commonly Used Materials Aluminum and Copper Alloys 9.2024(aluminum, O, T3, T4 or T6) 10.3003(aluminum, H12 or H16) 11.6061(aluminum, T6) 12.7075(aluminum, T6) 13.C268(copper) Other metals 14.Titanium 6-4 15.AZ63A (magnesium)

7. Ken YoussefiSJSU, ME dept. 6 Most Commonly Used Materials Plastics 16.ABS 17.Polycarbonate 18.Nylon 6/6 19.Polypropylene 20.Polystyrene Ceramics 21.Alumina 22.Graphite Composite materials 23.Douglas fir 24.Fiberglass 25.Graphite/epoxy

8. Ken YoussefiSJSU, ME dept. 7 Application of Most Commonly Used Materials Component Material

9. Ken YoussefiSJSU, ME dept. 8 Application of Most Commonly Used Materials Component Material

10. Ken YoussefiSJSU, ME dept. 9 Application of Most Commonly Used Materials Component Material

11. Ken YoussefiSJSU, ME dept. 10 Properties of Most Commonly Used Materials Ultimate Strength in tension

12. Ken YoussefiSJSU, ME dept. 11 Properties of Most Commonly used Materials Yield strength

13. Ken YoussefiSJSU, ME dept. 12 Properties of Most Commonly used Materials Fatigue endurance limit (strength under cyclic loading)

14. Ken YoussefiSJSU, ME dept. 13 Properties of Most Commonly used Materials Density

15. Ken YoussefiSJSU, ME dept. 14 Cost of Most Commonly used Materials

16. Ken YoussefiSJSU, ME dept. 15 Example – Materials for table legs Luigi Tavolino, furniture designer, conceives of a lightweight table of daring simplicity: a flat sheet of toughened glass supported on slender, unbraced, cylindrical legs. The legs must be solid and as light as possible (to make the table easier to move). They must support the table top and whatever is placed upon it without buckling. What materials could one recommend.

17. Ken YoussefiSJSU, ME dept. 16 Example – Materials for table legs The Model The leg is a slender column of density ρ and modulus E. The load P and its length l are determined by design (fixed). The radius r of the leg is a variable. We wish to minimize the mass m of the leg. Objective function

18. Ken YoussefiSJSU, ME dept. 17 Example – Materials for table legs The constraint is that the legs must support a design load without buckling. Euler’s buckling equation The weight is minimized by selecting the subset of materials with the greatest value of the material index. where I = π r 4 /4 Solving for the free variable, r, and substituting it into the equation for m gives, Material properties =

19. Ken YoussefiSJSU, ME dept. 18 Example – Materials for table legs Solving the Euler’s formula for r, gives an equation for the thinnest leg which will not buckle: Material properties The thinnest leg is that made of the material with the largest value of the material index. Two material indices, To minimize the weight, both have to be maximize.

20. Ken YoussefiSJSU, ME dept. 19 Procedure for deriving material indices

21. Ken YoussefiSJSU, ME dept. 20 Modulus of Elasticity (E) vs. Density (ρ) Charts Constant guidelines

22. Ken YoussefiSJSU, ME dept. 21 Modulus of Elasticity (E) vs. Density (ρ) Charts

23. Ken YoussefiSJSU, ME dept. 22 Modulus of Elasticity (E) vs. Density (ρ) Charts

24. Ken YoussefiSJSU, ME dept. 23

25. Ken YoussefiSJSU, ME dept. 24 Summary of materials for table legs