Ng Unless Otherwise Stated Q1 A Answer The Following Question In One Or Two Sentences Each Question Carries Two Marks 1 (184.73 KiB) Viewed 32 times
Ng Unless Otherwise Stated Q1 A Answer The Following Question In One Or Two Sentences Each Question Carries Two Marks 2 (157.89 KiB) Viewed 32 times
ng unless otherwise stated Q1. a) Answer the following question in one or two sentences. Each question carries two marks (1) What are the conditions for formation of a brittle fracture? (ii) Along which crystallographic planes does the growth of a cleavage fracture in a body centred cubic (BCC) lattice take place? (iii) What are the stages (phases) of the development of the fracture process? (iv) Which groups of metallic materials are susceptible to brittle fracture? (v) Define a driving force of a crack? cabou b) With the help of neat diagrams, explain the three general types of impact-energy-versus temperature behaviour curves for engineering materials? (8 marks) c) Explain in less than a paragraph the influence of carbon content on the Charpy V-notch energy- versus-temperature behaviour for steel? (8 marks) d) A large plate is fabricated from a steel alloy that has a plane strain fracture of 98.9 MPa vm. If, during service use, the plate is exposed to a tensile stress of 860 MPa Vm, determine the minimum length of a surface crack that will lead to fracture. a Assume the value of Y is 1.50 and the safety factor is 2. (14 marks) Q2. of cycles to failure (S-Nlas a method of
Q2. a) Draw sketches of the variation of stress and the number of cycles to failure (S-N) as a method of presenting engineering fatigue data for ferrous and non-ferrous metals. Explain the differences in the two classes of metals. (12 marks) b) State four measures that may be taken to extend fatigue life (8 marks) c) State the Miner's rule for cumulative fatigue damage effects (8 marks) d) A fatigue test was conducted on a sample of structural component in which the mean stress was 130 MPa and the stress amplitude was 410 MPa. Calculate, Page 1 of 3
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