铝板材电磁超声检测中波的产生与传播过程分析

针对电磁超声波如何在非铁磁性金属板中产生的问题,研究了铝板中电磁超声波的产生和传播机理。利用有限元分析软件对铝板受偏置磁场作用,铝板内感生出涡流,在涡流的作用下产生洛伦兹力,最后在该洛伦兹力的作用下铝板内的质点发生位移形成电磁超声波的4个过程进行了仿真。仿真结果表明,通有高频电流的线圈正下方会感生出交变的涡流;在平行于铝板表面的静电场作用下,铝板表面上的质点受到垂直于其表面的洛伦兹力作用;板内质点在此垂直力的作用下振动产生电磁超声波;查看质点各个方向位移的变化直观地看出电磁超声波的衰减很大。最后通过对单个质点位移的仿真分析得出了质点位移最大的方向。

Finite element simulation of the generation and propagation processes of electromagnetic ultrasonic wave in aluminum plate test

Aiming at the problem of how to generate electromagnetic ultrasonic wave in metal plate,the generation and propagation mechanism of ultrasonic wave in aluminum plate is studied,and four ultrasonic wave generation processes are simulated using the finite element analysis software.The four processes are: the aluminum plate is affected by the electrostatic field;the eddy current is induced in the aluminum plate;the workpiece surface suffers the Lorentz force and under the action of the Lorentz force,the crystal lattice in aluminum plate starts vibrating to generate electromagnetic ultrasonic wave.The simulation analysis shows that the coil with high frequency current will induce alternating vortex beneath the coil.Under the action of the electrostatic field parallel to aluminum plate,the particles in the aluminum plate suffer the Lorentz force perpendicular to the plate surface.The particles affected by the vertical force start vibrating to generate electromagnetic ultrasonic wave.Through observing the variation of the particle displacements in various directions,great decay of the electromagnetic ultrasonic wave can be seen intuitively.Through the simulation analysis of a single particle displacement,the largest particle displacement direction is obtained.