结构动力修改预测的摄动—迭代法

PREDICTION OF STRECTURAL DYNAMIC MODIFICATION BY PERTURBATION-ITERATION METHOD

首先将复模态参数灵敏度计算公式转化为矩阵摄动的形式,证明了复模态情况下一阶摄动的收敛性,构造了两种形式的摄动——迭代公式,并用于结构动力修改预测。摄动——迭代法综合了矩阵摄动法和模态缩减法两者的优点,计算公式简明,编程容易,且收敛速度快,修改量较大时也能得到较高的精度,应用该方法对一台磨床的结构薄弱环节进行了修改预测,获得了较满意的结果。

Perturbation-iteration method has been introduced to predict the structural dynamic modification in this paper. By transforming the formulae for evaluating modal sensitivity into matrix perturbation form, we can prove the convergence of first degree perturbation and develop two forms of perturbation-iteration formulae for the prediction of structural dynamic modification. This method includes the merits of both matrix perturbation and modal condensation methods. Such evaluation formulae are simple and clear, easy to program and quick to converge. Higer accurate result can be approached even in case of larger amount of modification. By applying this method to predict the modification of weak link for structure, satisfactory result has been obtained.