ME 3190-Summer 2023 Quiz 3 and 4

Question 5 Answer the following questions concisely (no more than half a page per question): a What do you understand by strength, stiffness and stability in the Mechanics of Solids context? b Identify, sketch and explain how to calculate all possible failure modes of a bicycle chain (for the link plates and the pin). c What is/are the difference(s) between von Mises (Maximum Distortion Energy) and Tresca (Maximum Shear Stress) failure criteria? d Give a structural engineering explanation to the placement of pinnacle statues on top of flying buttress columns of Gothic Cathedrals. e Give a structural engineering explanation to the structural failure of the "grabbing" arms of the capture vehicle used to raise the Russian submarine K- 129.

The answer is one of the options below please solve carefully and circle the correct option Please write clear .

Question 5 Answer the following questions concisely (no more than half a page per question): a What do you understand by strength, stiffness and stability in the Mechanics of Solids context? b Identify, sketch and explain how to calculate all possible failure modes of a bicycle chain (for link and pin). c Explain with your own words the concept of shear centre. d Give a structural engineering explanation to the placement of pinnacle statues on top of flying buttress columns of Gothic Cathedrals. e Explain, with your own words, the concept of Fatigue and give two examples of fatigue induced failure.

Q1/ The table below shows the values of stress amplitude and life cycles : Fatigue strength Sf (Mpa) Number of cycles (Nf) 474 111 417 496 352 3002 316 7065 290 21930 262 66075 The test were done, to estimate the failure, on un-notched axially load specimens under zero mean stress. Calculate a and b using the stress -life equation.

What is the value of shear stress if the torque exerted on a 6 mm diameter brass specimen was 20 N.m.? nD4 J = 32 TD T = 2J %3D Select one: O a. 471.5 kPa O b. 127.234 MPa O c. 471.5 GPa O d. 0.4715 GPa

10. The following results were obtained in a tensile test on a mild steel specimen of original diameter 20 mm and gauge length 40 mm. Load at limit of proportionality 80 kN Extension at 80 kN load 0.048 mm Load at yield point 85 kN Maximum load 150 kN When the two parts were fitted together after being broken, the length between gauge length was found to be 55.6 mm and the diameter at the neck was 15.8 mm. Calculate Young's modulus, yield stress, ultimate tensile stress, percentage elongation and percentage [Ans. 213 kN/mm2; 270 N/mm²; 478 N/mm²; 39%; 38%] reduction in area.