CAJ | 학술논문

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。
건립료포함렬문결함적이유금속판모형。채용유한원방법，대구유불동심도렬문적재료내부초성파장진행계산，획득료불동렬문심도금속재료상표면적회파신호，분석료렬문심도대초성파전파특성적영향규률。진일보분리제취불동계차저면회파적빈보특정，획득료유렬문결함인기적초성쇠감계수수빈솔적변화관계。최후제출료통과저면회파빈보도변식근표면렬문결함적방법。
A two-dimensional isotropic plate model with an embedded horizontal crack was established. Finite element analysis with absorbing boundary condition was employed to simulate the experimental pulse-echo mode to obtain ultrasonic data. The effect of crack depth on the wave propagation was studied and the spectra of different backwall echoes were further extracted. A relationship was determined between ultrasonic attenuation due to the crack and frequency. Finally, a method was proposed for identifying subsurface cracks based on the spectra of backwall echoes.