Identification of Dynamic Forces on Aircraft Engine Mounts With the Least Squares Method
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摘要: 飞机舱内噪声与振动控制的一个关键技术是获取发动机安装节处的动态力,从而实现对发动机振动引发的机体结构振动和舱内噪声进行预测和控制.但对于飞机,在飞行状态下不可能对发动机安装节处的动态力进行直接测量.通过采用最小二乘法正则化逆运算,利用地面状态下发动机安装节至吊挂或发动机安装节至安装节上的结构频率响应函数,以及飞行状态下吊挂或发动机安装节上相同位置处的振动加速度响应,对发动机安装节上的动态力进行识别.通过对比逆运算过程中的矩阵条件数,判定两组动态力识别的相对准确度.通过对两组数据识别的动态力均方根值进行对比,确认通过最小二乘法识别的发动机安装节动态力满足工程使用要求.Abstract: For aircraft noise and vibration control, it is vitally important to identify dynamic forces on engine mounts caused by engine operation. Although such dynamic forces are needed to predict and control structural vibration and structure-borne noise in the cabin, they cannot be measured directly in the flight state. The least squares method was employed to identify the dynamic forces based on the frequency response function (FRF) between excitation points and response positions with the actual acceleration measurements in the flight state. A norm condition number criterion was used to evaluate the accuracy of the inverse calculation process, and relative errors of the predicted dynamic forces were calculated. The results show that, the identified forces meet engineering requirements.
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Key words:
- dynamic force identification /
- least squares method /
- FRF /
- engine mount
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