基于实测频响函数反推管路卡箍支承刚度与阻尼

为了有效创建航空发动机管路系统动力学模型,需要获得动载荷作用下管路卡箍支承刚度及阻尼。提出一种基于实测频响函数(FRF)反推卡箍支承刚度及阻尼的方法。确定了针对单管路双卡箍支撑系统的反推辨识流程；利用自编有限元创建了该管路系统的动力学模型,并给出了求解频响函数的方法；进一步,提出了基于灵敏度的卡箍支承刚度和阻尼反推辨识算法；以典型管路卡箍为例,用所提出的方法辨识出了该卡箍的支承刚度和阻尼。将辨识值回带到理论模型中,发现仿真及实测固有频率及相对应的频响函数偏差均小于9%,从而证明了研发的辨识方法的合理性。另外,辨识结果也表明卡箍的刚度及阻尼具有频率依赖性,且水平及竖直方向存在差异。 

Inverse identification of support stiffness and damping of hoop based on measured FRF

To create the dynamic model of the aeroengine pipeline system effectively, it is necessary to obtain mechanical characteristic parameters of the hoop such as the support stiffness and damping under dynamic load. An inversed method for identifying the support stiffness and damping was proposed based on the measured frequency response function (FRF). The inverse identification procedure was determined for the single pipeline supported by double hoops. The dynamic model of the pipeline system were created by the developed finite element method, and the formulas of solving the FRF of pipeline system was also given. The inverse identification algorithm based on sensitivity analysis was proposed to identify the stiffness and damping of the pipeline hoop. A typical pipe hoop was chosen as an example to obtain the support stiffness and damping. The identified mechanical characteristic parameters of the hoop were inputted into the created finite element (FE) model. It was found the relative errors between calculated and measured natural frequency and corresponding FRF were less than 9%. Then, the rationality of the developed identification method was validated. In addition, the identification results indicate that the support stiffness and damping of the hoop are frequency dependent, and the horizontal and vertical values of these parameters are different.