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以超声的热弹激发机理为基础,建立了模拟激光在管道中激发周向导波的有限元模型.为了验证模型的正确性,根据Gao等人报道的实验条件[J.Appl.Phys.91,6114(2002)]进行了模拟,理论模拟结果与Gao等人的实验结果符合很好,说明本数值模型的正确性.在此基础上,模拟激光在不同厚度、不同曲率半径的管道内激发的周向导波波形,同时分析了激光在管道中激发的周向导波波形与平板中激发Lamb波的差异,以及管道厚度和曲率半径对激光激发周向导波的影响.
Based on the thermo-elastic excitation mechanism of ultrasonic wave, a finite element model (FEM) was established to simulate the laser induced circumferential guided wave in the pipeline.In order to verify the correctness of the model, according to the experimental conditions reported by Gao et al. [J.Appl.Phys.91, 6114 (2002)], the theoretical simulation results are in good agreement with the experimental results of Gao et al., Which illustrate the correctness of the numerical model. On this basis, simulated laser excitation in pipes with different thicknesses and different radii of curvature The circumferential waveforms were analyzed. The differences between the circumferential waveforms excited by the laser in the pipeline and the excited wave in the slab and the influence of the thickness and the radius of curvature on the circumferential guided wave were analyzed.