摘要
由于超声波能穿透闭合型裂纹界面,采用传统的线性超声技术难以检测和定位闭合型裂纹损伤,基于非线性时间反转理论研究了闭合型裂纹损伤检测方法。通过金属铝板上黏贴的压电激励/传感阵列,进行了Lamb波检测螺栓模拟的闭合型裂纹实验。根据Lamb波时间反转原理,得到激励重构信号。通过计算激励信号和重构信号间的相关系数定义了损伤指数,开发了能定位闭合型裂纹的成像算法。实验结果表明非线性超声时间反转方法能够有效地识别非线性的闭合型裂纹。
Initial cracks in metallic structures incline to be closed at rest. Such incipient damage generally fails to be detected and located with traditional linear ultrasonic techniques because ultrasonic waves can penetrate the contact interface of closed cracks. An imaging algorithm based on nonlinear ultrasonic time reversal method was proposed to detect closed cracks in aluminum plates. Two surface-bonded piezoelectric transducer（ PZT） arrays were used to generate,receive and re-emitted ultrasonic wave signals. The closed crack was simulated by tightening a bolt on the aluminum plate. By applying large amplitude excitation voltage on the PZT transducers,the closed crack could be opened and closed. The signals of transmitted waves recorded by PZT array,containing nonlinear components,were time reversed,emitted back,and the tone burst reconstructions were achieved. The correlation coefficient between the original excitation signal and the reconstructed signal was calculated to define the damage index for individual sensing path,and was further used to develop an imaging algorithm to locate the closed crack on the plate. The experimental results demonstrate that incident wave signals and their reconstructed signals can be used to accurately detect and locate closed cracks.
出处
《振动与冲击》
EI
CSCD
北大核心
2015年第9期95-101,130,共8页
Journal of Vibration and Shock
基金
国家自然科学基金资助(51078293
51378402)
