摘要
采用COMSOL Multiphysics软件建立了预制初始裂纹的TC4钛合金板热力耦合模型,分析了激光超声过程中多探测点表面波传播特性及与裂纹信息的表征关系,研究了探测点位置、裂纹深度及形状对裂纹回波信号特征的影响规律,克服了现有激光检测研究中无法精确表征裂纹的不足.结果表明,当激光源位置不变时,探测点越接近裂纹,表面裂纹回波抵达时间越短,幅值也逐步衰减;随裂纹深度的增长,表面裂纹回波的峰值也在增长,并且在裂纹深度大于1.0 mm时呈快速线性增长趋势;通过三种裂纹形状波形比对,发现裂纹形状对检测精度的影响可忽略不计;通过对转换横波和裂纹回波路径与抵达时间的计算,实现了对裂纹深度的表征及定位,检测误差不大于4％.
Abstract
The present study establishes a thermal coupling model for TC4 titanium alloy plates containing prefabricated cracks using COMSOL Multiphysics.The objective is to analyze the relationship between ultrasonic wave propagation characteristics at various detection points and crack information to enhance crack characterization in inspection studies.The influence of detec-tion point location,crack depth,and shape on the crack echo is investigated.The results indicate that with a fixed laser source position,a closer detection point to the crack leads to a shorter peak time and faster amplitude decay in the crack echo.Further-more,the crack echo peak value increases as crack depth grows,displaying a rapid and linear growth pattern for depths excee-ding 1.0 mm.The comparison of crack shape waveforms suggests that its impact on detection accuracy is negligible.By calcu-lating the path and arrival time of the converted transverse wave and crack echo,the crack depth is characterized and located with an accuracy of less than 4％.
基金项目
北京高校高精尖学科建设机械工程(21010221002)
国家级大学生创新创业计划项目(2022J00180)
NETL
NSTL
万方数据