Perform fatigue analysis of a bolted joint subjected to cyclic external loading.

The bolt experiences cyclic stress due to portion of external load (determined by joint stiffness ratio C). Mean stress sigma_m = Fi/At + C.Fe_max/(2At), alternating stress sigma_a = C.Fe_a/At, where Fi is preload, At is tensile stress area, Fe is external load, C = kb/(kb+km). Apply fatigue criteria: sigma_a/Se + sigma_m/Sut < 1/FoS (Goodman). For rolled threads, Kf approximately equals 2.2-3.0. Include endurance limit modifications. Critical design parameters: increase preload (reduces alternating stress), reduce C (stiffer joint members), use higher grade bolts, specify rolled threads after heat treatment.