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表面粗糙是材料制造过程中必有的副产物,粗糙表面会引起其中传播的声表面波的速度发生变化.在利用激光声表面波对材料性质进行评估时,常用宽带的激光声表面波速度频散特性对材料性质进行反演.为了研究表面粗糙度是否能作为反演的特征参数之一,本文建立了激光在表面粗糙样品中激发声表面波、聚偏氟乙烯换能器宽带接收声表面波的实验装置来研究不同粗糙度表面对声表面波速度的影响;理论上建立了激光在粗糙表面中激发声表面波的计算模型,利用有限元法得到声表面波的时域特征,并进一步得到声表面波的速度色散曲线,理论结果和实验结果能很好地拟合.这为利用激光声表面波对表面粗糙的评估提供理论和实验依据.
Surface roughness is an essential by-product of the material manufacturing process, the rough surface will cause the speed of the SAW propagating changes in the use of laser surface acoustic wave to evaluate the material properties, the use of broadband laser surface acoustic wave velocity In order to study whether the surface roughness can be used as one of the characteristic parameters of the inversion, a laser is used to stimulate the surface acoustic wave in a rough sample, and the surface of a broadband PVD receiving transducer Wave experimental device to study the influence of different roughness surfaces on the SAW velocity. The calculation model of the surface acoustic wave excited by the laser in the rough surface is theoretically established. The time-domain characteristics of the SAW are obtained by the finite element method. The velocity dispersion curve of SAW is obtained, and the theoretical results and experimental results can be fitted well, which provides theoretical and experimental basis for the evaluation of surface roughness by laser surface acoustic wave.