基于三维有限元的火箭模态振型斜率预示方法研究

Mode Shape Slopes Prediction Methods Based on 3D Finite Element Model

振型斜率火箭是姿控系统设计的重要参数,对飞行任务的可靠性与安全性有着至关重要的作用。依据全箭动特性的测量原理及参数定义,结合三维有限元建模方法和模型修正技术,全面考虑了速率陀螺、惯组安装位置处的局部刚度对振型和振型斜率的影响,建立了基于局部细节精细化建模的全箭模态振型斜率预示方法,并总结了3种不同的振型斜率提取方法,提高了振型斜率的预示精度。同时提供了三维模型振型一维化的方法,解决了使用三维有限元模型计算弹性运动方程式系数的难题。

Vibration mode shape slope has been a primary issue of concern for attitude control system,which is vital for flight reliability and safety.In this paper,with reference to the principle of launch vehicle modal test and parameter definition,a mode shape slopes prediction method is proposed.Using 3 D finite element modeling and model updating method,the effect of the local stiffness of structure where inertial components are installed is considered.Three different methods are summarized,which can help enhance the accuracy.The method of changing the modes of a 3 D model to the modes of a 1 D model is also presented,which can solve the problem of using 3 D model to calculate the parameters of the attitude dynamics model.