The Influence of Hole Processing and Joint Variables on the Fatigue Life of Shear Joints. Volume I.

摘要

Four hundred eighty fatigue test specimens were cycled in constant amplitude fatigue, using four designs, zero, 5, 50, and 100% load transfer, with two fasteners installed, and processing conditions such as hole diameter and angle, surface roughness, fastener preload, faying surface fretting protection, and hole cold-work, individually varied. The data was collected in computer files, and multiple stepwise regression analysis performed with specimen life as the dependent variable. A family of 15 models for predicting variation in fatigue lives was developed. Factors most effective were determined. Hole surface roughness was found generally either not to enter into the predictive equations, or to enter very weakly into the model. When hole roughness entered the models, its effects were almost equally divided between increasing roughness showing increases or decreases in fatigue life. Fastener interference was determined to be a key parameter in determining fatigue life. Interference was approximately twice as effective as hole cold-working in fatigue life enhancement. (Author)