烧蚀机制下激光超声声场的模拟与实验验证

分析了烧蚀机制下超声波的产生机制,建立了工件有限元模型,将等离子体的冲击力对材料的作用视为超声波的激励源,模拟计算了激光超声波在工件中的传播过程,提取了节点位移的时间历程曲线,求出超声波的速度并由此确定相应超声波的类型。此外,分析了激光超声声场分布,利用半圆形铝质试块进行了激光超声的测量对比实验,采用超声换能器接收纵波、横波以及表面波。通过对比分析可知,数值分析结果与实验数据相符,该有限元数值模拟方法正确可靠。

Simulation and experiment of laser ultrasound field under ablation mechanism

The ultrasound generation mechanism was analyzed under ablative mechanism.The finite element model of a workpiece was established.The impact force of plasma on the material was taken as the ultrasound drive source.The propagation process of laser ultrasound was simulated in workpiece.The time course curve of node placement was calculated,and the speed of an ultrasound was calculated,and then the type of an ultrasound was determined.In addition,the field distribution of laser ultrasound was analyzed.The measuring contrast experiment of laser ultrasound was done by using semicircle aluminum block.In contrast experiment,the longitudinal wave,shear wave and surface wave were received by ultrasound transducer.The results of contrast analysis show that the results of numerical analysis are consistent with the experimental data,and the finite element numerical simulation method is accurate and reliable.