基于有限元及修正梯度法的材料二维缺陷弹性波识别

文章研究了一种利用弹性波识别二维缺陷形状的方法。采用有限元方法直接由入射场计算散射场,反演计算中采用二元三角基函数将扰动函数展开,并取残差模量的梯度作为迭代收敛的方向,同时引入梯度因子与梯度相乘以对其进行修正从而加快收敛,通过对扰动函数的反演识别出缺陷的形状。从算例可以看出,此方法能够有效地识别材料的二维缺陷。

2-D Flaws of Material Identification Using Elastic Wave Based on Finite Element Method and Modified Gradient Method

The method of 2-D flaw identification using elastic wave is studied in this paper. The fringe field is obtained direct- ly from the incident field through FEM. The disturbed function is expanded according to the bivariate circular function in the inversion calculation. The gradient factor is introduced and modified to accelerate the convergence along the gradient of residual modulus, and the shape of the flaws is identified through the inversion of disturbed function. From the examples, the 2-D flaws of materials are identified effectively based on this method.