频域子结构方法在力学环境预示中的应用研究

目的利用频域子结构方法(FBSM,FRF Based Sub-structuring Method)对结构的力学环境进行准确高效地预示。方法分别对处理子结构间为刚性连接和弹性连接两种问题的FBSM进行理论推导。为了验证FBSM的正确性,设计连接为刚性连接和弹性连接两种算例结构,并将FBSM对算例结构频响函数的计算结果与有限元方法(FEM,Finite Element Method)的对应计算结果进行对比。其中,弹性连接利用空间梁单元进行等效,并将该等效方法与利用六自由度标量弹簧的等效方法进行对比。结果对于刚性连接和弹性连接两种情况,FBSM对频响函数的计算结果均与FEM的对应计算结果吻合程度良好。此外,空间梁单元的结点刚度矩阵为非对角阵,与六自由度标量弹簧相比,可更为准确地等效工程实际中的弹性连接。结论FBSM可对结构的力学环境进行准确高效的预示,且在处理具有弹性连接结构的力学环境预示问题时,可采用空间梁单元等效弹性连接。

Application of FRF Based Sub-structuring Method in Prediction of Mechanical Environment

Objective To predict the mechanical environment of structure correctly and efficiently with FRF Based Sub-structuring Method (FBSM). Methods The FBSM employed to predict the mechanical environment of structure with rigid and elastic joint were deduced, respectively. Meanwhile, two example structures, with rigid and elastic joint respectively, were designed to validate the obtained FBSMs via comparing the corresponding calculation results of FRF achieved through FBSM and Finite Element Method (FEM). The elastic joint was equivalent with spatial beam element and the advantages of this equivalent method were compared with 6-DOF scalar spring to simulate the elastic joint. Results The calculation results obtained by FBSM were in good agreement with them achieved via FEM no matter the joint was rigid or elastic. Additionally, since the node stiffness matrix of the spatial beam element was a non-diagonal matrix, spatial beam element held the advantages of simulating the actual engineering elastic joint more precisely compared with 6-DOF scalar spring. Conclusion FBSM could predict the mechanical environment of structure correctly and efficiently. Moreover, the spatial beam element and other equivalent elastic connection could be used to predict mechanical environment of elastic connection structure.