复合材料裂纹参数对Lamb波非线性系数的影响研究

INFLUENCE OF CRACK PARAMETERS ON THE LAMB NONLINEAR INDEX OF ULTRASONIC IN COMPOSITE

针对复合材料中裂纹的检测问题,建立了考虑裂纹接触非线性特性的各向异性复合材料的3D波动数值模型,研究非线性Lamb波与含有不同尺寸裂纹的复合材料的作用关系,探讨裂纹的长度和宽度对Lamb波非线性系数的影响。研究结果表明:一定范围内,裂纹长度的增加将导致Lamb波的非线性系数增加;裂纹宽度的增加将导致Lamb波的非线性系数减小。利用SNAP非线性超声检测设备,试验验证了通过超声检测非线性系数进行复合材料裂纹检测的可行性,这对后续进行复合材料的非线性无损探伤具有重要意义。

For detection of cracks in composite,a 3D finite element wave model of anisotropic composite plate considering the nonlinear crack contact was established to explore the interaction between nonlinear Lamb waves and different sizes of cracks in composite structure. The influence of the length and width of cracks on the nonlinear index of nonlinear Lamb waves was explored. The results show that the nonlinear index increases with the increase of the length of cracks within a certain range. As the width of cracks increases,the nonlinear index decreases. Using the SNAP nonlinear ultrasonic testing device in experiment,the feasibility of crack detection in composite materials by testing ultrasonic nonlinear index was verified. The experimental results show that the presence of cracks in the structure can be qualitatively evaluated by measuring the nonlinear index in the composite. This is of great significance to the follow-up nonlinear non-destructive testing of composite materials.