Thermoelastic wave induced by pulsed laser heating
Thermoelastic wave induced by pulsed laser heating
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DOI：
10.1007/s003390000593
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发表时间：
2001-07
期刊：
影响因子：
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通讯作者：
Xinwei Wang;Xianfan Xu
中科院分区：
文献类型：
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作者：
Xinwei Wang;Xianfan Xu
本文给出了脉冲激光加热下半无限固体中热弹性平面波的一般解。该解考虑了热传导中的非傅立叶效应和温度与应变率之间的耦合效应，在超短脉冲激光加热中起着重要的作用。在此基础上，计算研究了纳秒、皮秒和飞秒激光脉冲引起的应力波。结果表明，在表面最大温升相同的情况下，脉冲激光越短，产生的应力波越大。非傅立叶效应导致表面温升较高，但应力波较弱。此外，首次发现第二应力波的形成和传播速度与热波相同。伴随热膨胀的表面位移对飞秒激光脉冲表现出很大的时间延迟。相反，在纳秒和皮秒激光加热中，表面位移和加热同时发生。结果表明，在飞秒激光加热过程中，耦合效应强烈地衰减了应力波，延长了应力波的持续时间。这可能解释了在超短激光材料加工中损伤最小的原因。
In this work, a generalized solution for the thermoelastic plane wave in a semi-infinite solid induced by pulsed laser heating is developed. The solution takes into account the non-Fourier effect in heat conduction and the coupling effect between temperature and strain rate, which play significant roles in ultrashort pulsed laser heating. Based on this solution, calculations are conducted to study stress waves induced by nano-, pico-, and femtosecond laser pulses. It is found that with the same maximum surface temperature increase, a shorter pulsed laser induces a much stronger stress wave. The non-Fourier effect causes a higher surface temperature increase, but a weaker stress wave. Also, for the first time, it is found that a second stress wave is formed and propagates with the same speed as the thermal wave. The surface displacement accompanying thermal expansion shows a substantial time delay to the femtosecond laser pulse. On the contrary, surface displacement and heating occur simultaneously in nano- and picosecond laser heating. In femtosecond laser heating, results show that the coupling effect strongly attenuates the stress wave and extends the duration of the stress wave. This may explain the minimal damage in ultrashort laser materials processing.