Shown below is a horizontal beam that is fixed at the left

Last updated: 6/21/2023

Shown below is a horizontal beam that is fixed at the left end and is cyclically operated at the right end by a vertical actuator that deflects it 3 mm up and 10 mm down both from the horizontal position The frequency of cycling is 2 Hz The beam is 250 mm long and has a rectangular cross section of 20 mm width The beam s material is a steel with Sut 440 MPa Syt 370 MPa and a fully modified Se 250 MPa a Using a factor of safety of 1 5 determine the thickness of the beam h for a life of 1 000 hours b Suppose a small hole of 4 mm diameter is drilled at the mid width of the beam at a distance 150 mm from the left end The beam thickness is the same as that determined in Part a Can the beam survive 1 000 cycles of cyclic operation now Justify your answer with calculations 250 mm h K