Stress and Fracture Analysis of Tapered Attachment Lugs

Attachment lugs are frequently used in aerospace applications to connect major structural components. It is important to assess the structural integrity of such lugs with cracks present. These assessments are necessary to prevent abrupt failure of the lugs before their intended service lives are reached. The estimation of the associated fatigue life of a lug, which consists of crack initiation and crack growth periods, demands stress and fracture analyses of the lug. In this paper, the results of two-dimensional stress and fracture analyses of tapered attachment lugs subjected to symmetric and off-axis loadings are presented. The effects of various parameters such as the outer-to-inner diameter ratio, crack length, and crack location on the tangential stress distribution, pin contact pressure distribution, stress concentration factor, fatigue critical location, and stress intensity factor are investigated. The finite element method utilizing a crack-tip singularity element is used in the analyses.