钛合金空心风扇叶片成形三维有限元分析

Three Dimensional FEM Simulation of Titanium Hollow Blade Forming Process

摘要:

随着高旁路涡扇发动机在军用、民用飞机上的应用，采用超塑成形/扩散连接(SPF/DB)技术制造大尺寸钛合金宽弦风扇叶片已经成为涡扇发动机的一项关键制造技术。钛合金空心风扇叶片的成形过程包括3个阶段：扭转成形、热成形、超塑成形。在本研究中，为了分析空心风扇叶片的成形过程，建立了一个三维有限元模型，钛合金的变形行为符合Backofen方程。通过三维有限元模型，分析扭转速率、热成形模具下落速度、超塑成形目标应变速率、板材与模具之间的摩擦系数、芯板和面板的厚度比等参数对成形力的影响规律。研究表明，随着扭转速度、热成形模具的下落速度、目标应变速率、板材厚度比的提高，成形力将提高，而摩擦系数对成形力的影响很小

Abstract:

With the introduction of high by-pass turbofan engines into both commercial and military aircraft industries, the fabrication of large size fan blade through superplastic forming/diffusion bonding (SPF/DB) has become a pivotal technique of turbine fan engine. There are three key steps to form a hollow blade: twisting, hot forming and SPF. In this study, a three dimensional finite element method (FEM) model is established to simulate the forming process of titanium fan blade, in which the mechanical behavior of TC4 obeys Backofen’s equation. Based on the numerical modeling, the influences of key factors such as the twisting rate, descending velocity, frictional coefficient, strain rate, the sheet thickness ratio of core sheet to face sheet on the forming force were studied. The results show that with increasing of the twisting rate, descending velocity, strain rate, the sheet thickness ratio of core sheet to face sheet, the forming forces increase; however the frictional coefficient has little influence on the forming force