论文部分内容阅读
建立了包含裂纹缺陷的二维金属板模型.采用有限元方法,对具有不同深度裂纹的材料内部超声波场进行计算,获得了不同裂纹深度金属材料上表面的回波信号,分析了裂纹深度对超声波传播特性的影响规律.进一步分离提取不同阶次底面回波的频谱特征,获得了由裂纹缺陷引起的超声衰减系数随频率的变化关系.最后提出了通过底面回波频谱图辨识近表面裂纹缺陷的方法.
A two-dimensional metal plate model with crack defects was established.Using finite element method, the ultrasonic field inside the material with different depth cracks was calculated, and the echo signals of the upper surface of the metal material with different crack depth were obtained.The influence of crack depth on ultrasonic wave And the influence law of the propagation characteristics.Furthermore, the spectral features of the bottom echoes of different orders were extracted and separated, and the relationship between the attenuation coefficient and the frequency of the ultrasonic attenuation coefficient caused by the crack defects was obtained.Finally, method.