基于重力梯度测量系统的组件结构模态分析

重力梯度测量系统设计过程中，对重力梯度旋转平台中仪表的位置特性有严格要求。按照传统的设计流程，等到结构件设计、安装完毕再进行振动试验能充分反映结构的真实位移，但是会消耗大量的时间及人力成本，效率较低。对此，本文采用数值模态分析方法在实际生产之前对整体结构进行了较为详尽的有限元分析，计算出了前十阶模态频率和振型，并且检验了结构设计中的刚度问题。对样机结构进行修改，从而保证了一阶主频率达到539.74 Hz,从而满足了航空搭载的环境要求。对整体结构的模态分析为重力梯度旋转平台工程样机的研制奠定了基础。

Modal Analysis of the Structure of the Gravity Gradient Test System

In the process of the gravity gradient measurement system design, position properties of the instruments in the gravity gradient rotary platform were rigorous. According to traditional design and test method, the real displacement of the structure was been obtained by libration test with more cost of manpower, time and lower efficiency. So, numerical modal analysis method was adopted here and a more detailed finite element analysis for the overall structure was acquired before production. The top ten ranks modal frequencies and mode shapes were calculated by analyzing and stiffness problem in structure design was proved. The further study showed that the optimization of prototype structure according to the modal analysis may be ensuring its first-order main frequency meeting with the requirement of airborne environment by 539.74 Hz. Than the requirement by plane was met. Modal analysis of the structure laid the foundation for the development of the gravity gradient rotary platform engineering prototype.