Stress Analysis of Horizontal Tail Joint of a Transport Aircraft and Fatigue Life Estimation

Attachment joints are generally high load transfer regions in the airframe structure. Because of the connection between two members through fasteners, there will be stress concentration in these components. High tensile stress locations are invariably the crack initiation locations due to fatigue. Failure of the attachment joints could lead to the catastrophic failure of the airframe structure. The current project includes the stress analysis of an attachment structural member, which connects HT with vertical tail (VT). In a T-tail configuration the HT will be sitting at the tip of VT. Bending moment and shear load created because of the aerodynamic load distribution on HT will be transferred to VT through attachments at the root. Loads representative of a small size transport aircraft will be considered in this study. Finite element analysis of the attachment member will be carried out to identify the location of maximum stress and the stress distribution in the bracket region. Refinement of the analytical model will be carried out to accurately predict the magnitude of high tensile stress. Fatigue damage calculation will be carried out using Miner’s linear damage theory. S-N curve for aluminum alloy material obtained from the literature will be used in fatigue damage calculation.