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中文核心期刊

超短激光脉冲加热薄板的广义热弹扩散问题

A GENERALIZED THERMOELASTIC DIFFUSION PROBLEM OF THIN PLATE HEATED BY THE ULTRASHORT LASER PULSES

  • 摘要: 由于超短激光脉冲具有功率密度高、持续时间短、加工精度高等优势, 近年来被广泛应用于超精细加工、光学储存和微电子器件制造等领域. 本文基于L-S型广义热弹扩散理论, 建立了考虑材料记忆依赖效应和空间非局部效应的记忆依赖型非局部广义热弹扩散耦合理论, 它能够准确预测几何尺寸与内部特征尺寸相近结构的热弹扩散瞬态响应. 推导了所建理论的控制方程, 并基于拉普拉斯积分变换获得了控制方程的解. 作为算例, 利用所建理论和求解方法研究了半无限大薄板受非高斯激光脉冲加热和化学冲击联合作用下的热弹扩散瞬态响应问题, 得到了薄板的温度、化学势、位移、应力和浓度等随非局部参数、热时间迟滞因子和扩散时间迟滞因子等参数变化的分布规律. 结果表明: 传热对传质影响显著, 传质对传热影响甚微; 非局部参数对位移、应力影响显著, 对温度、化学势和浓度几乎没有影响. 该理论及求解方法的建立, 旨在实现材料在机械、热、化学势等冲击作用下传热传质瞬态响应的准确预测.

     

    Abstract: In recent years, ultrashort laser pulses are widely used in the fields of ultra-precision machining, optical storage and microelectronic manufacture due to the advantages of high power density, short duration and high machining accuracy. In the manuscript, the memory-dependent nonlocal generalized thermoelastic diffusion theory is established based on the L-S generalized thermoelastic diffusion theory as well as considering the memory-dependent effect and spatial nonlocal effect. The theory can accurately predict the thermoelastic diffusion responses of structures whose geometry size is equivalent to its internal characteristic scale. The control equations of the theory are derived, and the solution of the control equations are obtained based on the Laplace integral transformation. As a numerical example, the transient thermoelastic diffusion responses of a semi-infinite thin plate subjected to a non-Gaussian laser pulse and a chemical shock are studied. The variation of the temperature, chemical potential, displacement, stresses and concentration with different nonlocal parameters, thermal time delay factors and diffusion time delay factors are obtained. The results show that heat conduction has significant effect on mass transfer, while mass transfer has little effect on heat conduction; nonlocal parameter has significant influence on displacement and stress, but little effect on temperature, chemical potential and concentration. The establishment of this theory and the solution method are aimed at accurately predicting the transient responses of the heat and mass under the impact of mechanical loading, heat and chemical potential.

     

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