基于振动声调制和时间反转法的微裂纹定位检测研究

针对常规超声检测对闭合微裂纹不敏感的现象,开展了基于振动声调制技术的非线性超声检测研究,并引入时间反转法对检测信号中的非线性信号进行聚焦处理,实现闭合微裂纹的检测及定位。利用ABAQUS有限元软件仿真振动声调制技术检测铝管微裂纹,用有限长冲激响应滤波器提取检测信号中的一阶旁瓣非线性信号,在时域反转后重新加载到无裂纹铝管模型进行时反信号聚焦仿真。结果表明,振动声调制检测信号中的一阶旁瓣非线性信号能够在裂纹位置附近聚焦,管道径向布置的时间反转信号加载方式信号聚焦效果优于轴向布置,并且根据聚焦像的大小和位置可以对裂纹进行定量和定位。

Study of the Metal Micro Crack Location Based on Vibro-acoustic Modulation and Time Reversal Method

In order to overcome the shortage that traditional linear ultrasonic testing is insensitive to the closed cracks, the nonlinear ultrasonic testing research based on vibro-acoustic modulation(VAM) was studied and the time reversal(TR) method was used to focus nonlinear signal. Finite element software ABAQUS was used to simulate micro crack detection of aluminium tube based on VAM, the first order sideband of VAM signal was extracted by finite impulse response(FIR) filter and was reversed in the time domain. Then reloaded TR signal on the nondestructive tube model and carried out the time reversing focusing simulation with ABAQUS. The results show that the first order sideband is able to focus around original crack location, the diametrical arrangement of TR signals load position is superior to axial arrangement, and crack dimension and location can be measured base on the time reversal focusing imaging.