扩展有限元与遗传算法相结合的结构缺陷反演分析

建立扩展有限元法与遗传算法相结合的结构缺陷反演分析模型.扩展有限元法通过引入不连续位移模式使得网格剖分无需依赖结构内部的不连续界面.通过改变水平集函数表征结构缺陷（夹杂）的位置和大小，遗传算法在每次迭代过程中具有全局和局部搜索能力，通过评估响应测点的响应量适应度值决定是否进一步迭代.对带有单个圆形缺陷（夹杂）和多个缺陷（夹杂）的结构进行了反演分析，并就响应测点的布置进行了讨论.结果表明，建立的反演分析模型能准确地探测结构存在的单个甚至多个缺陷（夹杂）.

THE INVERSE ANALYSIS OF INTERNAL DEFECTS (INCLUSIONS) IN STRUCTURES USING A COMBINED XFEM AND GA METHOD

An inverse analysis model for identifying internal defects (inclusions) in the structure using a combined method of the extended flnite element method (XFEM) and the genetic algorithm (GA) is proposed. The discontinuous displacement mode introduced in the displacement function of the XFEM makes it possible to generate a grid independent of the discontinuous interface of the structure. The locations and the size of defects are determined by a modiflcation of the level set function in the study. The GA has a global and local optimization ability in each iteration process. The fltness value of the response determines whether the iteration should continue or not. Two numerical examples including a single circular defect and multiple defects are analyzed, and the locations of the response measuring points in the structure are also discussed. Results indicate that the inversion model presented in the paper can accurately identify the locations and the size of a single defect or multiple defects in the structure.