结合型分布带状分段移动热源模型

Segment-moving heat source model with strip-shape and combined distribution of heat flux

在数值模拟分析大型焊接结构的焊接残余应力和变形时,可以采用分段移动带状热源模型以便提高计算效率.为此,首先试验分析了不同焊接速度对焊接温度场带状特性的影响.并在已建立的结合型分布圆形热源模型的基础上,推导出了结合型分布带状分段移动热源模型的节点热流与加载时间的计算公式.结果表明,焊接速度大于4mm/s时,较长区段的温度场已经具有带状分布特点.此外,与高斯分布带状分段移动热源模型的节点热流与加载时间的计算公式相比,推导出的公式不但与总的热输入量有关,还与电弧和熔滴的热量分配比有密切的关系.

Segment-moving heat source model of strip-shape is high computational efficiency in the numerical simulation of the welding residual stress and distortion of large welded structures. To improve the computational efficiency,the influence of the different welding speed on the strip characteristics of welding temperature field is analyzed by experiments. And expressions of node heat flow and loading time in the segment-moving heat source model with the strip-shape and combined distribution of heat flux are derived based on the established circular heat source model of the combined distribution of heat flux. The results show that the longer section of the temperature field has already the strip shape as the welding speed is more than 4 mm/s. In addition,comparing with the expressions of node flow and loading time of segment-moving heat source model with the strip-shape and Gaussian distribution of heat flux,the derived expressions relate to not only the heat input sum but also the heat splitting ratio of arc and droplet.