A beam is simply supported by two pin joints 400 mm apart Th

A beam is simply supported by two pin joints 400 mm apart. The beam has a squarecross section 15.0 mm by 15.0 mm. The beam supports a fixed load of 1000 N,uniformly distributed along its length. It also supports an oscillating point load at its center that varies between -500 and +500 N.

An engineer who graduated from Ohio State designed the beam to have a life of 5.00 x 107 cycles. The beam was made from an alloy with a yield strength of 350 MPa, atensile strength of 425 MPa, and whose fatigue properties are given by Basquin’s law:

After the beam has been subjected to 8 x 106 cycles, the OSU engineer is fired forincompetence. You are hired to replace him.   The only practical way of extending thelife of the beam to meet its original design specification is to reduce the uniformlydistributed (static) load. Calculate the new distributed (static) load required to ensure thatthe beam does survive for its original design life. (770 N)

Solution

The answer of following questions is as follows .

The new distributed static load requires is 34 kn/m this load will survive for the original design life.