基于有限元法的螺栓连接结构模态参数识别

通过有限元预紧力单元模拟螺栓预紧力的方法计算量较大,不太适合大型螺栓连接结构的工程计算。基于有限元软件MSC./Patran,将螺栓连接结构视为层单元,应用层单元法和多点约束技术对典型的L形螺栓连接结构建立了有限元模型,并完成了模态分析,将模态计算结果与完全刚性连接的一体化简化模型的模态分析结果及实际结构的模态实验结果进行了比较。研究表明,该方法的计算结果与实验结果较一致,且计算量小,为有预紧力作用下螺栓连接结构的有限元计算提供了准确可靠的计算方法。

Identification of Bolt Connected Structure Modals Based on FEM

For its enormous time consumption,the method to simulate preloads of bolt connected structures using preload elements in FEM software is not suitable for engineering calculation of large structures.Based on the platform of FEM software MSC./Patran,simulating bolt connected structure with cell elements,a finite element model of a typical "L" shape bolt connected structure was built by using cell element method and multiple point constrain technique,and the modal analysis of the structure was carried out.The modal analysis results were compared with the results regarding the bolt connected structure as a whole body and with the results of experimental modal analysis.It’s shown that the above method takes a relative short time to calculate modal results,however the calculated results are in agreement with the experiments.This paper provides an accurate and reliable FEM to calculate bolt connected structure with preloads on it,and it has reference value for finite element modeling and vibration modal analysis for complex bolt connected structures with preloads in engineering.