附件机匣振动力学行为及寿命分析

附件机匣作为航空发动机的重要部件,获得其寿命指标至关重要,在对附件机匣壳体进行疲劳寿命分析时,需要充分考虑其复杂多样的工作环境以及各载荷情况。基于ANSYS Workbench有限元仿真,计算得到了附件机匣在考虑自身重力和固定约束条件、轴承载荷、温度场以及振动载荷谱共同作用时的应力响应功率谱密度。采用雨流循环计数方法并通过MATLAB编程计算得到附件机匣的疲劳寿命。结果表明:振动谱沿Z轴得到的等效应力值最大,且最大点的应力响应PSD谱中σx的总均方根值远大于其余应力。单独采用σx应力PSD谱和采用所有应力PSD谱计算得到的寿命相差仅50 min,因此可采用RMS最大的σx应力PSD谱计算附件机匣的疲劳寿命。

Analysis of Vibration Mechanics and Lifetime of Accessory Gearbox

Accessory gearbox is a key component of aeroengine, and acquisition of its lifetime index is critically important. When analyzing the fatigue lifetime of accessory gearbox case, the complex and diverse working environment and loading conditions should be considered. Based on ANSYS Workbench finite element simulation, the stress response PSD of accessory gearbox was calculated,which taken own gravity, fixed constraints, bearing loads, temperature field,and vibration load spectrum into account. After that, the fatigue lifetime was calculated according to the rain-flow counting method through MATLAB program. The results show that the equivalent stress of the vibration spectrum along the Z-axis is max, and the RMS of the stress response PSD at the max point is much greater than the rest of the stress. The difference of the lifetime calculated between using stress response PSD individually and all stress response PSDs is only 50 minutes. Thus, the maximum RMS stress PSD can be used to calculte the fatigue lifetime of accessory gearbox.