焊接热源计算模式的研究进展

总结了计算焊接温度场过程中焊接热源模式的改进过程。首先讨论了传播学中常用的以集中热源为基础的线热源与面热源的解析模型、以及能量在空间以高斯函数形式分布的焊接热源模式，以高斯分布函数为基础，引出了半球能量密度分布的热源模式、椭球能量密度分布的热源模式、双椭球能量密度分布等焊接热源模式。并对比了不同热源分布函数对计算结果的影响，讨论了不同焊接计算过程中对热源函的选择。结果表明，通常的工程运算仍可采用解析模型函数进行化计算，高斯分布函数、半球能量密度分布函数、椭球能量密度分布函数常应用在有限元计算过程中，但由于未精确考虑电弧对熔池的冲击作用，在熔池附近有一定误差，而双椭球能量密度分布的热源模式，不仅可以处理一般的电弧总力小的焊接热源，也可以处理具有强烈穿透作用的激光焊和电子束焊过程的焊接热源，进一步提高焊接热源循环的计算精度。

The Development of Models about Welding Heat Sources' Calculation

This paper summarizes progress in the development of models for calculating the flow of heat in welding.First,an analytic model which is most usually used as centralized point or line and face heat source was put forward.Then a mathematical model for weld heat source based on Gaussian distribution of power density in space was presented.Other models based on Gaussion distribution function were hemispherical power density distribution,ellipsoidal power density distribution,double ellipsoidal power density distribution.The computed temperature distribution in different models was compared and an opinion was made to select different model under different condition.It was shown that the analytic model was more simple and practical,it can be used in many projects.But it had some error near the pool for not considering the effect of penetration arc.The model of double ellipsoidal power density distribution can deal with both the shallow penetration arc welding processes and the deeper penetration laser and electron beam processes and make the calculated value more accurate.