空气涡轮起动机整机结构动力学分步建模与确认策略

Hierarchical Modeling and Updating Strategy for the Structural Dynamics of an Air Turbine Starter

针对空气涡轮起动机整机结构复杂、有限元模型建模与修正困难的问题,提出了整机结构分步建模与模型确认的策略。根据起动机的结构特点,将其分解为若干子系统,再依次将子系统分为若干底层结构。首先建立底层每个单个结构无约束状态的有限元模型,并通过非接触式激光测振分别对结构进行模态测试,利用测试的模态数据实现有限元模型的修正,得到确认的有限元模型;其次通过确认的底层结构的连接建模,得到子系统层的有限元模型,同时对底层结构装配后的子系统进行模态测试和子系统层连接模型的参数修正,得到确认的子系统模型;最终利用转子系统与静子系统的支承刚度,建立起动机高精度的整机动力学有限元模型并进行整机的临界转速仿真预测,并与起动机整机临界转速的试验数据对比,验证分步进行整机动力学高精度模型的建模与确认策略的可行性。

Due to the complex structure of the air turbine starter and the difficulty of modeling and validation of the finite element model,a strategy of step-by-step modeling and validation of the whole structure is proposed.According to the structural characteristics of the ATS,it is decomposed into several subsystems,and then the subsystems are divided into several bottom layer structures in turn.Firstly,the finite element model of each individual structure in the bottom layer is established in the unconstrained state,and each structure is tested separately by non-contact laser vibration measurement,and the modal data from the test is used to modify the finite element model to obtain the validated finite element model;secondly,the finite element model of the subsystem layer is obtained through the connection modeling of the confirmed bottom layer structure,at the same time,modal test on the subsystem after the assembly of the underlying structure was conducted,and the parameters of the subsystem layer connection model were modified to obtain the validated subsystem model.Finally,a high-precision finite element model of the dynamics of the whole machine is established using the support stiffness between the rotor system and the static subsystem,and the critical speed of the whole machine is predicted by simulation.This strategy has a high practical value in engineering.