Some aircraft component is fabricated from an aluminum alloy that has a plane strain fracture toughness
of 35 mpa m (31.9 ksi in. ). it has been determined that fracture results at a stress of 250 mpa (36,250 psi)
when the maximum (or critical) internal crack length is 2.0 mm (0.08 for this same component and alloy, will
fracture occur at a stress level of 325 mpa (47,125 psi) when the maximum internal crack length is 1.0 mm (0.04
why or why not?

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.

What are the two (02) benefits, which may result from a successful implementation of preventive maintenance (pm) program in an organization? (clo3)a)- lean manufacturing b)-overlapping responsibilities c)-the planner is not qualified d)-accurate contractor information e)-reduction in equipment redundancies f)-accurate stores information