నైరూప్య

Fatigue Damage Estimation for a Fuselage Structure with Multiple Cut-outs under Cyclic Loading

Remya Varghese, Manu Jayakumar

Discontinuities are common in airframe structure. These lead to the emergence of stress concentration regions. This turns deliberately pronounced when airframe structure experiences fluctuating loads during flight. These elevated tensile stress locations undergoing fluctuating loads may lead to fatigue cracks. In case of situations where these cracks are unnoticed they could lead to catastrophic failure of the structure. So it is highly pertinent to involve in the stress analysis of a segment of the fuselage with multiple cut-outs and fatigue damage calculation due to fluctuating pressurization loads. The fatigue damage calculation requires constant amplitude S-N data for various stress ratios and local stress history at the stress concentration. Fatigue life prediction methodologies through damage calculation are empirical in nature and therefore require test validation. Here CATIA software is used for the modelling, MSC PATRAN is used for meshing the fuselage panel and stress analysis is carried out using MSC NASTRAN.