Modal Analysis of Wing Considering Transient Thermal Effects

Abstract

The severe aerodynamic heating on the surface of modern hypersonic flight vehicle, that can bring high temperature and large temperature gradients in the structure of the vehicle, will be a challenge for the vehicles design and multidisciplinary optimization. The transient thermal environment consists of high temperature and large temperature gradients will generate two important problems related to vehicle structure, namely: 1) the material property, such as elastic modulus, will be degraded at elevated temperature, and 2) the non-uniform thermal stress cased by large temperature gradients will change the stiffness distribution of wing structure, which can make the modal frequencies and shapes of structure changed remarkably. Firstly, the theory and methodology of structure modal analysis in transient thermal environment is outlined. Subsequently, the transient temperature field of structure considering aerodynamic heating is obtained by employing computational technology of aerodynamic heating/structure heat transfer coupling program. Finally, the modal frequencies and shapes of vehicle structure under transient temperature field is calculated based on finite element method (FEM). Based on the analysis and investigation of the simulation results, the influence of the transient thermal environment on structure modal frequency and shape is determined. Furthermore, the investigation of wing structure modal analysis considering aerodynamic heating is an important basis of aerothermoelastic simulation.