you are given a 7/16-in-dia, class 7 bolt with rolled threads is preloaded to 70% of its proof strength when clamping a 2.75 in-thick sandwich of solid steel. you are also to find the safety factors against fatigue failure, yielding and joint separation when a 1000 lbf (peak) fluctuating external load is applied. there is only 1 bolt used. the bolt modulus and the member are the same. hence, you are to calculate the joint factor and its coefficients followed by all the fatigue parameters. for this question, what is the value of the local mean fatigue stress () on the bolt in units of psi?
