APPLICATION OF NEW ENERGY BASED FATIGUE LIFE ASSESSMENT METHOD FOR OPTIMIZING UAV WING DESIGN

Abstract

Aerospace industry is the core of every economy worldwide. With the advent of new and innovative high tech aerial vehicles, there is a constant need to improve the design and stability criteria to explore the margins towards a more cost effective design. This research presents an application of new a finite element procedure based on the energy methods for calculation of fatigue life of an aircraft wing structure. The constitutive laws based on the energy methods were developed previously to devise a finite element procedure. This procedure has already been implemented on a component level for a turbine blade. For this research, a wing structure made of Al6061-T6 has been selected. Static analysis with unit load at the wing tip was used to get the initial deflection for the entire assembly. Subsequently modal analysis was carried out to determine the natural response for the structure. The frequency response analysis was finally performed to get the actual structural response under the dynamic load. The finite element approach based on strain energy dissipation per cycle that has already been developed was then used for extraction of fatigue contour plots for the entire structure thereby giving the fatigue life for the entire assembly on an elemental level. These fatigue plots are then utilized in performing optimization for the wing structure based on the accumulated fatigue life cycles.