钛合金宽弦风扇叶片的振动特性

通过模态仿真和模态试验技术分别对某型号TC4钛合金宽弦风扇叶片的振动特性进行研究。采用ANSYS-APDL软件对风扇叶片模型进行模态仿真分析。根据风扇叶片的坎贝尔图以及不同模态的振型分布，识别风扇叶片的弯扭振型。风扇叶片不同转速不同模态下的转速裕度和频率裕度分析显示:第1阶弯曲模态在红线转速下的转速裕度和频率裕度超过20%，表明风扇叶片满足共振裕度要求。在三轴向振动台上利用扫描式激光测振仪，采用敲击法和随机带宽激励的方法测量叶片的响应，分析了风扇叶片不同模态的冲击响应特性和多轴响应特性，发现风扇叶片在周向和轴向激励下的响应以低阶弯曲模态为主，而在径向激励下的响应以扭转和复合模态为主，不同激励位置不同模态的响应特性与风扇叶片的振型息息相关。 

Vibration characteristics of titanium wide-chord fan blade

An analysis of vibration characteristics of a TC4 titanium alloy wide-chord fan blade was conducted with both modal simulation and modal test methods. Modal analysis of a fan blade model was conducted by ANSYS-APDL software. Based on the Campbell diagram and mode shapes of the blade, the bending and torsional modes were identified. Analysis of rotating velocity margin and frequency margin of various speed illustrated that both margins of the first order bending mode were over 20%, satisfying the requirement of resonance margin. Pulse impact method and random excitation method were utilized on the three-axis shake table with scanning vibrometer to analyze the response characteristics of impact and multi-axial excitations. Results showed that low-order bending mode response was high due to circumferential and axial excitations, while high-order torsional and combined mode responses were high due to radial excitations. Blade responses of different excitation points and modes were related to the mode shapes.