摘要
由于在复合材料板中传播的超声导波具有偏斜效应,使得理论群速度与试验测得的群速度不一致,因此需要对群速度幅值和传播方向进行校准。数值计算复合材料板中超声导波频散方程得到S0模态各个方向的理论相速度频散曲线。运用群速度校准法则对S0模态群速度幅度和传播方向进行修正。校准后的理论群速度与试验测得的群速度较为吻合。试验中采用频率200 kHz的S0模态对碳纤维复合材料板中的模拟缺陷进行检测。结果显示采用校准后群速度和试验测得的群速度可准确定位缺陷,且具有很好的一致性。因此,采用群速度校准法则可有效提高各向异性复合材料结构中超声导波的缺陷定位和识别能力。
Due to ultrasonic guided waves propagating in composite plates are characterized with skew effect, it makes there exists a certain discrepancy between experimentally measured and theoretical group velocities. Therefore, it is needed to calibrate the amplitude and propagation direction of group velocity. Dispersion equation of ultrasonic guided waves in the composite plate is numerically solved and theoretical phase velocity dispersion curves of So mode at different directions are obtained. The amplitude and propagation direction of group velocities of So mode are calibration based on group velocity calibration principle. Calibrated and experimental group velocities are well matched. In experiments, So mode at 200 kHz is used to inspect the artificial defect in the carbon fiber composite plate. Experimental results show accurate localization of the defect can be achieved by using calibrated and experimental group velocities and localization results by using these two types of group velocities are consistent with each other. As a result, the abilities of defect localization and identification of ultrasonic guided waves can be effectively enhanced by using group velocity calibration principle in composite plates.
出处
《机械工程学报》
EI
CAS
CSCD
北大核心
2012年第20期8-15,共8页
Journal of Mechanical Engineering
基金
国家自然科学基金(50975006
51075012
11272021)
北京市自然科学基金(1122007)
北京市教委科技计划(KM201010005003)
北京市科技新星计划(2008A015)资助项目
关键词
超声导波
群速度
偏斜效应
复合材料板
缺陷检测
Ultrasonic guided waves Group velocity Skew effect Composite plate Defect detection
