Simulation of stress, strain and heat generation in landing gear

Abstract

COMSOL Multiphysics is a finite element analysis software which allows an individual to study a set of problems under different operating conditions. In this project, COMSOL version 4.3b, an updated version was used to study the heat and stress generation of the landing gear during an aircraft's landing using the multibody dynamics and heat transfers in solids modules. Landing gear is an important structural component of the aircraft and the taking off and landing of the aircraft is considered the most crucial and dangerous operations during a flight. The landing gear consists of several sub -components which include the tyres, shock absorber, steering and retraction system. Attention would be focused on the shock absorber. Steel 4340 was used as a control material in this simulation. Three other materials; Titanium alloy (Ti-6Al-4V-2Sn), Aluminium alloy (7175-T736) and Composite (Graphite - Epoxy) are recommended as alternative materials for this project. Four different aircraft weight categories; 5000kg, 10,000kg, 15,000kg and 20,000kg were deployed to study the changes in the heat and stress generation in those four materials. The model was built using the COMSOL multiphysics and different boundary conditions and variables were set for this simulation.

After the simulation, results showed that Steel 4340 and Titanium alloy (Ti-6Al-4V-2Sn) were the most ideal materials for landing gear as both maximum stress experienced were below the ultimate tensile strength and the temperature were below the melting point. Results showed that the maximum stress experienced by Composite (Graphite-Epoxy) were much below the ultimate tensile strength, however, it breaches over the melting point. For Aluminium alloy (7175-T736), the temperature experienced was below the material's melting point, however, the stress had exceeded the ultimate tensile strength. Thus, these two materials are deemed unsuitable. Steel 4340 is still better recommended than Titanium alloy (Ti-6Al-4V-2Sn) because of its lower cost. It was also observed that the stress curve generated took shape in the form of cyclic loading, thus future studies could utilise the fatigue module to give a more comprehensive study. In addition, for the purpose of future works, a more complex model could be built, however, this would require an individual to have an expert knowledge of this subject.