叶根缘板过渡处特征模拟件双轴弯曲振动疲劳试验研究

Experimental Investigation on Biaxial Bending Vibration Fatigue of Blade-Like Specimen for Fillet Between Airfoil and Platform

针对转子叶片叶根缘板过渡处高应力比弯曲振动疲劳问题,采用转子叶片结构细节刻画方法设计了特征模拟件,实现了对叶根缘板过渡特征的几何刻画和应力分布模拟。基于模态差异化方法,搭建了模拟件双轴弯曲振动加载系统,实现了轴向拉伸-高频弯曲振动的转子叶片典型双轴载荷施加。试验过程中试样处于高频弯曲振动状态下(>1kHz),测得的试样考核点弯曲应变幅稳定。试验结果显示试样宏观断裂位置与有限元计算最大应力点一致,对断口进行了宏/微观分析确定了试样断口疲劳源与裂纹扩展特征,证明采用结构细节刻画方法进行试样设计的合理性及所搭建试验加载系统可行性。

Aiming at the high stress ratio bending vibration fatigue of fillet feature between the rotor blade and the platform,the rotor blade structure detail description method was used to design the blade-like specimen,which achieved the geometric description and stress distribution simulation of the fillet feature. The biaxial bending vibration loading system was presented based on modal difference concept,achieving axial tensile and bending vibration typical biaxial load of the rotor blade. During the test,the specimen was in the state of high frequency bending vibration(>1 kHz),and the monitored bending strain amplitude of the specimen was stable. The macro fracture position of the specimen is consistent with the FEM results. The fatigue source and crack propagation characteristics of the specimen fracture were determined by macro/micro analysis,which proves the feasibility of the design concept.