A cylindrical pressure vessel of radius 1.2m and thickness 4 mm is made from Ductile steel. a. If the pressure if varied cyclically between 0 and 0.4p, for the resulting cyclically varying combined biaxial stress state, estimate the equivalent mean stress, stress amplitude and stress ratio. b. Using the Soderberg fatigue failure criteria estimate value of the pressure p that will lead to failure after 108 cycles. The material yield strength is 300Mpa and the fatigue strength is 250 MPa (at 108 cycles).

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.

Coiled springs ought to be very strong and stiff. si3n4 is a strong, stiff material. would you select this material for a spring? explain.

Give heat transfer applications for the following, (i) gas turbines (propulsion) ) gas turbines (power generation). (iii) steam turbines. (iv) combined heat and power (chp). (v) automotive engines