圆柱型涂层/基底系统中的激光超声表面波
Laser thermo-elastic generated surface acoustic waves on cylindrical coating-substrate system
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摘要: 为了分析圆柱型涂层/基底系统中声表面波的特点及其传播特性,以热弹激发机理为基础建立了脉冲激光在圆柱型涂层/基底系统中激发超声表面波的有限元程序。在此基础上,计算了激光在铝(涂层)/镍(基底)和镍(涂层)/铝(基底)系统中激发的超声表面波波形,它们分别对应了硬涂层系统和软涂层系统。结果表明,圆柱型涂层/基底系统中的超声表面波是色散的,并且其色散特性由弯曲柱面引起的几何色散和涂层/基底系统引起的色散共同决定,这使得圆柱型涂层系统中色散特性远比板状涂层系统杂,不存在简单的正常和反常色散规律。Abstract: To investigate the propagation of acoustic surface waves in a cylindrical coating-substrate system,a finite element algorithm is put forward to simulate laser inducing acoustic surface wave in cylindrical coating-substrate system based on the thermoelastic mechanism.Using this algorithm,the waveforms of laser-induced acoustic waves on the aluminum(coating)/nickel(substrate) and nickel(coating)/aluminum(substrate) system are simulated.The results show that surface acoustic wave on the cylindrical coating-substrate system is dispersive.When surface acoustic waves are propagating along the cylindrical structure,there exists geometry dispersion,which makes the dispersion property of the cylindrical coating system more complex than that of a plate coating system.As a result,there is not simple rule for predicating the dispersive property of surface acoustic waves on cylindrical coating-substrate system.
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