太阳翼结构地面模态试验时重力导致的几何非线性不能忽略,因此提出了一种考虑重力影响的柔性结构动力学模型修正方法.首先推导了地面环境下结构的切线刚度矩阵,求解广义特征值,得到重力影响下的模态,对试验和计算得到的模态振型进行匹配,并进行参数的灵敏度分析,选取合适的修正参数并迭代求解参数的修正量.以展开锁定情况下的太阳翼组合结构为研究对象,对比研究发现重力对模态频率有影响,采用分步修正策略,依次对单翼板弹性参数和翼板间连接刚度进行修正,研究结果表明本文方法不仅收敛速度较快,且具有较高的精度.
The geometric nonlinearity caused by gravity can not be neglected when conducting ground modal test of solar array on the ground. So a new model updating method for flexible structures considering the influence of gravity is proposed in this paper. First, the stress stiffness matrix in ground environment is derived, then the modes are calculated by solving the generalized eigenvalue problem. After matching tested mode shapes with calculated ones, the sensitivity analysis of the parameters is carried out. Then the proper parameters are chosen and updated by using a iteration process. A numerical simulation of a deployed and locked solar array is conducted, it is found that gravity has influence on the modal frequency. The elastic parameters of the single panel and the connection stiffness of the hinges between different solar array panels are updated step by step. The study shows that proposed method is fast and accurate.