Ken Youssefi Product Design and Manufacturing, SJSU 1

Most Commonly Used MaterialsThe 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)

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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 6-415. AZ63A (magnesium)

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Most Commonly Used Materials

Plastics

16. ABS17. Polycarbonate18. Nylon 6/619. Polypropylene20. Polystyrene

Ceramics

21. Alumina22. Graphite

Composite materials

23. Douglas fir24. Fiberglass25. Graphite/epoxy

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Application of Most Commonly Used MaterialsComponent Material

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Application of Most Commonly Used MaterialsComponent Material

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Application of Most Commonly Used Materials

Component Material

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Properties of Most Commonly Used Materials

Ultimate Strength in tension

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Properties of Most Commonly used Materials

Yield strength

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Properties of Most Commonly used Materials

Fatigue endurance limit (strength under cyclic loading)

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Properties of Most Commonly used Materials

Density

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Cost of Most Commonly used Materials

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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.

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Example – Materials for table legsThe 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

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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 = πr4/4

Solving for the free variable , r, and substituting it into the equation for m gives,

Material properties

=

Ken Youssefi Product Design and Manufacturing, SJSU 15

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.

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Procedure for deriving material indices

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Modulus of Elasticity (E) vs. Density (ρ) Charts

Constant guidelines

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Modulus of Elasticity (E) vs. Density (ρ) Charts

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Modulus of Elasticity (E) vs. Density (ρ) Charts

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Ken Youssefi Product Design and Manufacturing, SJSU 21

Summary of materials for table legs