基于二级近似的航天器结构的模型修正方法

Model Updating of Spacecraft Structure Based on Two-level Approximate Function

目的基于航天器结构自由度数大且结构复杂,直接对有限元模型修正计算效率低的问题,利用二级近似方法来提高有限元模型修正的计算效率。方法根据特征向量建立Ritz空间推导出频率响应及其敏度的一级近似计算公式,利用近似函数二级近似计算结构参数变化后的动刚度矩阵,通过多重优化流程消除近似计算引入的误差。结果通过两个数值算例进行验证,该方法提高了结构模型修正的计算效率。结论该方法适用于航天器结构的模型修正。

Objective To improve the computational efficiency of model updating with two-level approximation method based on large-scale degrees of freedom and the complexity of the spacecraft structure. Methods The first-level approximate calculation formula for frequency response and its sensitivity was derived with Ritz space based on eigenvectors. The dynamic stiffness matrix after structural parameter changes was calculated by approximation function. The errors caused by approximate calculation were eliminated by multiple optimization. Results The method improved the computational efficiency of model up-dating by two numerical examples. Conclusion The method is suitable for model updating of spacecraft structure.