Unformatted text preview: IE370/Fall 2011 Due: 09/11/2011 Homework 1 1. What role does manufacturing play relative to the standard of living of a country? (1’) 2.
Give examples of a job shop, flow shop, and project shop. (2’) 3.
How does a manufacturing system differ from a manufacturing process? What are the definitions of machine tool, job and operation? (2’) 4.
What manufacturing processes need to make use of mass diffusion? (2’) 5.
What manufacturing processes needs to take consideration of the following thermal properties respectively: 1) melting points, 2) thermal conductivity and 3) thermal expansion? (3’) 6.
What are the mechanical and physical properties commonly associated with metallic materials, ceramic materials and plastic materials respectively? (3’) 7.
Take a cubic piece of metal with a side length l and deform it plastically to the shape of a rectangular parallelepiped of dimensions l1, l2, and l3. Assuming that the material is rigid and perfectly plastic, show that volume constancy requires that the following expression be satisfied: ε1 + ε2 + ε3 = 0. (hint: true strain = Log (L/L0) (3’) 8.
In a tensile test on a metal specimen, true strain = 0.08 at a stress = 265 MPa. When the true stress = 325 MPa, true strain = 0.27. Determine the strength coefficient and the strainhardening exponent in the flow curve equation. (2’) 9.
During a tensile test in which the starting gage length = 125.0 mm and the crosssectional area = 62.5 mm2, the following force and gage length data are collected (1) 17,793 N at 125.23 mm, (2) 23,042N at 131.25mm, (3) 27,579N at 140.05mm (4) 28,913N at 147.01 mm, (5) 27,578N at 153.00mm and (6) 20,462N at 160.10mm. The maximum load is 28,913N and the final data point (Data point 6) occurred immediately before failure. (a) Plot the engineering stress strain curve. Determine (b) yield strength, (c) modulus of elasticity and (d) tensile strength. (4’) 10. A copper wire of diameter 0.8mm fails at an engineering stress = 248.2 MPa. Its ductility is measured as 75% reduction of area. Determine the true stress and true strain at failure. (2’) 11. What is fatigue strength and endurance limit? (2’) 12. Why dynamic mechanical properties have to be considered in design of materials and manufacturing process? What are the typical manufacturing processes to increase the fatigue life of a metallic component (list 2~3)? (4’) o ...
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- true strain, stress strain curve.