Design of Wing Spar Cross Section for Optimum Fatigue Life

Abstract

Aircraft structure is the most obvious example where functional requirements demand light weight and strong structures. Shape and sizing optimization are being increasingly used nowadays for designing lightweight structural components. The aim of this paper is to present optimization of I-section integral wing spar made of aluminum 2024-T3. The efficient design, based on optimum fatigue life, was achieved using Extended Finite Element Method (XFEM) and its ability to simulate crack growth in complex geometry. The computations were carried out in Morfeo/Crack for Abaqus software which relies on the implementation of XFEM. Shape optimization of the aircraft wing spar beam was conducted by comparing the fatigue crack growth lives for different cross section shapes, but constant cross section area of the spar. The analysis revealed that XFEM is efficient tool for complex three-dimensional configurations optimization where extended fatigue life is one of the most important objectives.