Explain, at the microscale, the process of fatigue,
with emphasis on why metals experience fatigue.
A pressure vessel is made of aluminum alloy and
operates at 15 cycles per minute. It operates 50% of the time at a
stress amplitude of 1400 psi; the fatigue life at this stress level
is 1,000,000 cycles. The other 50% of the time a stress amplitude
of 2100 psi is exerted on the vessel; the fatigue life for the
material at this stress level...