Design and Analysis of Wing Spar to Enhance the Fatigue Life

In this study, the crack propagation behavior for the uniform wing spar and tapered wing spar with and without an intermediate cap was compared. Optimization of the I cross-section of integral aluminum 2024-T3 wing spar is presented, taking the maximum fatigue life as the criterion. Toward this aim, finite element method (FEM) is used to stimulate crack growth in I-beam. The stress intensity factor was calculated using fracture mechanics in ANSYS software. Life cycles and damages were calculated and compared to increase the efficient fatigue life of the spar. Wing spars with intermediate caps may extend light aircraft fatigue life; according to this study, top web and intermediary caps are intact, while the bottom cap usually fractures and fails. Analysis that was carried out showed that FEM could be an efficient and cost-beneficial tool for the simulation of crack propagation in three-dimensional structures like wing spars. The findings also suggest that engineers can better predict and optimize wing spar fatigue life by using FEM and ANSYS software during design and evaluation. This method increases aerospace structure safety, reliability, cost savings, and performance.