摘要本文研究了激光致铝靶产生熔融相变情况时，铝靶的温度场的分布特征。并在热传导方程的基础上对不同脉宽的长脉冲激光致铝靶产生热熔融破坏进行了数值研究。

依据长脉冲激光与铝靶相互作用的实际情况建立了半无限大轴对称模型，运用有限差分的方法模拟了其热熔融的过程，得到温度和熔融深度的解析解，从而得到了铝靶在激光作用下的破坏程度。进而讨论了激光致铝靶产生热熔融破坏的过程以及不同阶段的熔融深度。68002

此外，本文对不同脉宽的长脉冲激光致铝靶产生热熔融破坏的数值进行研究，分析不同脉宽激光造成的破坏结果。通过有限差分法的数值模拟，总结得到了脉冲宽度对熔融深度的影响。

    模拟结果显示，相同能量的激光作用于铝板时，熔融深度不随脉宽单调变化。脉宽较小时，熔融深度随脉宽的增加而增加；脉宽增加到某一个值，熔融深度最大；超过这个值后，熔融深度将随脉宽增加而减小。

    本文的研究可为长脉冲激光与金属相互作用出现温升、产生热熔融破坏提供理论依据，亦有助于研究脉冲激光加工的最优参数。

毕业论文关键词  长脉冲激光 铝靶 热熔融 数值模拟

毕业设计说明书（论文）外文摘要

Title   Numerical study on Thermal destruction of aluminum target induced by long pulse lasers in different pulses         

Abstract

The characteristics of aluminum target’s temperature field distribution induced by the laser is obtained in this paper. A numerical study on thermal destruction of aluminum target induced by long pulse laser of different pulses based on the heat conduction equation is conducted.

A semi-infinite axisymmetric model is established based on the actual situation of laser melting the aluminum targets, and the thermal melting process is simulated by using the finite difference method .The numerical solution of temperature and melt depth are obtained. Thus the damage level of laser melting the aluminum targets is obtained. Further more, the process of the laser melting the aluminum target and different stages of the melting depth are discussed.

Focuses on the numerical study on thermal destruction of aluminum target induced by long pulse lasers of different pulses, the damage results of different pulse laser are analyzed in this paper. By the numerical simulation of finite difference method ,the influence of pulse width versus melting depth is summarized.

The simulation results show that when the same  energy laser is applied to the aluminum plate,the melt depth is not monotonic with pulse.When the pulse width is small,depth of fusion increases with the pulse width.When the pulse width increases to a certain value,the depth of fusion rises to the maximum.When more than this value,melting depth will increase with decreasing pulse width.

The research consequences may offer theoretical and experimental references to the study of the temperature rising and the damage of thermal melting. It also help to study the option of parameters of pulsed laser processing.

Keywords  long pulse laser, aluminum target, thermal melting, numerical simulation.

目   次  

摘要 I

Abstract II

目次 IV

1 引言 1

1.1 激光与材料相互作用研究的背景和意义 1

1.2 激光与材料相互作用的研究现状 1

1.3 本文的主要研究工作 2

2 理论基础 2

2.1 铝的热物理性质 2

2.2 激光与物质相互作用的理论依据和过程 3

2.2.1 激光与物质作用的理论依据 3

2.2.2 激光与物质作用的过程 3