For the problem specified in the table, build upon the results of the original problem to determine the minimum factor of safety for fatigue based on infinite life. If the life is not infinite, estimate the number of cycles. The force F is applied as a repeated load. The material is AISI 1018 CD steel. The fillet radius at the wall is 0.1 in, with theoretical stress concentrations of 1.5 for bending, 1.2 for axial, and 2.1 for torsion.

In problem 3.80, The cantilevered bar in the figure is made from a ductile material and is statically loaded with Fy = 200 lbf and Fx = Fz = 0. Analyze the stress situation in rod AB by obtaining the following information.

(a) Determine the precise location of the critical stress element.

(b) Sketch the critical stress element and determine magnitudes and directions for all stresses acting on it. (Transverse shear may only be neglected if you can justify this decision.)

(c) For the critical stress element, determine the principal stresses and the maximum shear stress.

in 1-in dia Tin in in 6 in