Investigation on linear and nonlinear thermal buckling mode for high-speed thin-walled blade

Abstract

During the high-speed operation of the aircraft engine, the thermal shock load has an important effect on the stability of thin-walled blade, with the occurrence of large deformation and buckling characteristics. Based on thermal buckling equilibrium theory and modal theory, a dynamic model of thin-walled blade is built with the help of finite element method, and the linear and nonlinear response of thermal buckling can be analyzed under the thermal shock loading. The results have showed that the blade produced obvious torsional deformation under the effect of thermal load, and the largest deformation is happened on the blade tip no matter the linear or nonlinear response. For the instability characteristic of thin-walled blade, the critical load factor of nonlinear thermal buckling is relatively lower than that of linear buckling. Whilst, the critical load factor of linear bucking and nonlinear bucking can become larger with the increase of modal order. The unsteady response from thermal buckling and torsional deformation tends to produce large radial deformation. The distance between blade and inner wall of the casing is reduced to enhance more probability of friction impact. It is shown that thermal bucking analysis is a better choice for stability prediction and optimal-design of thermal-shock rotating blades.