【作者】 闫桂荣； 段忠东； 欧进萍；

【Author】 YAN Gui-rong, DUAN Zhong-dong, OU Jin-ping(Harbin Institute of Technology, Harbin 150090)

【机构】 哈尔滨工业大学；

【摘要】 结构模型修正是使理论有限元模型的计算模态参数在试验频段上与试验模态参数相一致的一种方法。由于传统的优化矩阵方法和优化元素方法的目标函数存在误导性,本文采用了改进的最优化元素型法(Zhongdong Duan等,2002)。基于优化方法的有限元模型修正问题归结于求解一个强非线性的约束优化问题,为了快速准确地求得全局最优解,本文采用了一种浮点数编码的遗传算法。该算法采用基于排序的选择算子,根据非线性的归一几何排名函数分配选择概率,并使用最优保存策略模型来进行优胜劣汰操作;针对浮点数编码,采用算术交叉算子和非一致变异算子。通过对一个7个自由度的质量一弹簧系统和一个复杂平面框架结构模型修正的数值计算,验证了基于遗传算法的改进的最优化元素型法的有效性。更多还原

【Abstract】 The Model Updating Technique (MUT) is a method to make reconciliation of the modal parameters of the theoretical FEM ( Finite Element Model ) with the test model in certain frequency domain. The Improved Optimal Elemental Method for Finite Element Model Updating proposed by Duan (Zhongdong Duan, etc., 2002) is employed herein, because this method define a new objective function, which is more consistent than traditional optimization based MUT. Optimization based MUT can be expressed as a strong nonlinear optimization problem with constraints. The traditional numerical algorithms can not escape from possible local entrapment, while Genetic Algorithm ( GA ) may produce a global-optimal solution. A Float-encoding Genetic Algorithm (FGA) is proposed for the solution of this problem. The GA is characterized by its ranking-like selection and the most superior individual in each generation is moved to the next generation directly in addition to being involved in the genetic process, which enhanced the convergence. According to the characteristics of the objective function, some corresponding simple and excellent genetic operators are mixed in use, which could deal with the global optimization problem quickly and effectively. Finally numerical applications to a 7 DOF(Degrees of Freedom) Mass-Spring System and a complicate planar frame structure are presented. The results testify that the Improved Optimal Elemental Method employing Genetic Algorithm is feasible and effective.更多还原