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材料的力学性能直接影响到构件的安全性和寿命,而材料的弹性常数是其力学性能的重要指标。利用有限元软件Abaqus模拟了激光激发的超声表面波和纵波在金属薄板试样表面及体内的传播过程。采用修正的高斯分布的力源等效激光对样品的脉冲作用来产生超声波,在边界处设置无限单元消除反射回波的干扰信号,并由接收点的超声表面波和纵波信号计算得到波速大小,再根据波速和弹性常数之间的关系得到材料的弹性常数。数值结果与理论解吻合良好,为激光超声检测材料弹性常数提供了一种十分有效的数值方法。
The mechanical properties of materials directly affect the safety and life of the components, and the material’s elastic constant is an important indicator of its mechanical properties. The finite element software Abaqus was used to simulate the propagation of laser-induced ultrasonic surface waves and longitudinal waves on the surface of the thin metal plate and in the body. The modified Gaussian distribution is used to generate the ultrasonic wave by the impulse of equivalent laser on the sample. An infinite element is set at the boundary to eliminate the interference signal of the reflected echo. The wave velocity is calculated from the ultrasonic surface wave and the longitudinal wave signal of the receiving point. Then according to the relationship between the wave velocity and the elastic constant to get the material’s elastic constants. The numerical results agree well with the theoretical ones, which provides a very effective numerical method for the ultrasonic testing of materials’ elastic constants.