基于频散特性的杆中超声波传播仿真

Simulation on Ultrasonic Propagation in Finite Rods Based on Frequency Dispersion Characteristic

针对超声实时在线检测中缓冲杆应用的局限性,以无限长杆的频散特性为理论基础,利用有限长杆的端面边界条件,分别以应力关系和应变关系为系统函数,建立了超声波在有限长杆中传播的系统模型。通过在杆端面施加激励,借助系统传输模型,获取回波信号,并与实验进行对比,验证该方法的正确性。同时得出了超声波在有限长杆中传播产生的多次回波的重复周期与杆半径之间成正比的关系。

In order to study buffer rods applying in real-time and on-line ultrasonic testing, the system model of the ultrasonic propagating in finite rods was built using the methods of stress-analysis and strain-analysis, which are both based on the frequency dispersion characteristic of stress wave in infinite rods and the end＇s boundary condition of finite rods. The models based on the stress-analysis and strain-analysis methods were analyzed, and the impulse signals were obtained respectively. The results of the simulation and the experiment validate that the two analytic methods are effective, and draw a conclusion that the periods of the ultrasonic impulse formed in finite rods is direct ratio to the radius of rods.