某稳瞄转塔结构的有限元模态分析与试验验证

FEM modal analysis and test validation for sight-stabilization turret structure

结构动态效应是影响稳瞄系统稳定精度的关键因素。目前有限元模态分析与试验模态分析结合的方法是分析结构动力学特性的最有效途径之一。以某型稳瞄具两轴四框架结构为研究对象,首先利用有限元方法进行了模态预分析。根据仿真结果获取的振型特征,对两轴四框架的外环进行模态测试,给出了前8阶模态的固有频率、振型和模态阻尼比。模态仿真与测试的结果相互验证表明:有限元仿真可实现两轴四框架结构固有频率相对误差小于15%的精度要求,在测点密度足够的条件下振型相关性良好。

The structure dynamic effect is a key factor to affect the stabilization accuracy.Currently,the most effective method to analyze the structure dynamics is to combine finite-element modal(FEM)analysis and experimental modal analysis.A two-axis and four-frame structure of a sight-stabilization system was taken as the research object of this paper.Firstly,the modal pre-analysis was completed using FEM.According to the vibration mode characteristics of simulation results,the modal for the out frames of two-axis and four-frame structure was tested.The natural frequencies,vibration modes and modal damp ratio were listed for the former 8-order modals.The mutual authentication between modal simulation and test shows that the accuracy level of the natural frequencies for two-axis and four-frame structure can be lower than15% using FEM and the relevance of the vibration modes are good in the case of enough test point density.