Answer Happy

Question: (20%) (A) A certain metal has a ductile behaviour is well described by a = 10000023. Work hardening process has been done for this material leads to area reduction ratio of r= 30%, find the yield stress of the work-hardened metal. (5 marks) (B) Let us assume that the metal in (A) above, still described by the same ductile behaviour equation, first is cold worked by 15% and then followed by an additional cold work of 20%, find the yield stress of this metal. (5 marks) (C) Discuss the difference between the two processes mentioned above and why the yield stresses are not same? (5 marks) (D) If the same bar of (A) above has a yield strength of 72000 N/m2 because of two stages of cold work processes, the first is unknown amount and the second was 25%. Determine the unknown amount of the initial cold work. (5 marks)

(A) 0 = 10000€ 0.24 , 15% € (B) initially 15% followed by 30% (D) 30%, yield strength of 70,000 N/m2