A machine part will be cycled at ±350 MPa for 5 (103) cycles. Then the loading will be changed to ±260 MPa for 5 (104) cycles. Finally, the load will be changed to ±225 MPa. How many cycles of operation can be expected at this final stress level? For the part, S = 530 MPa, f = 0.9, and has a fully corrected endurance strength of Se = 210 MPa.

Aloaded platform of total mass 500 kg is supported by a dashpot and by a set of springs of effective stiffness 72 kn/m. it is observed that when the platform is depressed through a distance x = 12.5 cm below its equilibrium position and then released without any initial velocity; it reaches its equilibrium position in the shortest possible time without overshoot. find the position and velocity of the loaded platform 0.10 sec. after its release. if a further load of 400 kg is added to the platform, find, i) the frequency of damped vibrations, and i) the amplitude of vibration after 2 complete oscillations, given that the initial amplitude is 15 cm.

Thermal stresses are developed in a metal when its a) initial temperature is changed b) final temperature is changed c) density is changed d) thermal deformation is prevented e) expansion is prevented f) contraction is prevented

Draw the engineering stress-strain curve for (a) bcc; (b) fcc metals and mark important points.