A level set approach for the simulation of the multipass hybrid laser/GMA welding process
A level set approach for the simulation of the multipass hybrid laser/GMA welding process
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DOI：
10.1016/j.commatsci.2014.04.036
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发表时间：
2014-08-01
影响因子：
3.3
通讯作者：
Guillemot, Gildas
中科院分区：
文献类型：
--
作者：
Desmaison, Olivier;Bellet, Michel;Guillemot, Gildas
提出了一种新的三维有限元模型，在水平集方法开发，模拟混合气体保护焊/激光焊多道焊条件。该传热传质模型耦合了热量守恒方程、动量和质量守恒方程的求解以及焊缝的发展。电弧焊接总功率分为两部分：一部分对应于通过熔化的填充材料的液滴传递到熔合区的能量，其余部分通过周围的等离子体传递到工件。液滴能量输入被建模为体积热源。关于与等离子体和激光加热相关的热表面通量，“连续表面力”的方法被用来模拟它们作为体积热源集中在紧邻的金属-气体界面。提出并讨论了一种解决方案，即忽略熔融区中的高速流体流动，通过使用增强的液体粘度。因此，液体的导热性被增强，从而导致到工件的真实的热传递。焊道的形成是通过在质量守恒方程中引入源项，并应用与金属-气体界面的平均曲率成比例的表面张力的法向分量来获得的。提出这种方法以减少计算时间。将该求解方案应用于18 MND 5（ASMESA 533）钢级的复合焊接模拟。结果进行了比较，实验测量和观察接近工业的条件下操作。的增强施加到液体的电导率系数的影响示出和讨论。当将其从物理值改变为焊接文献中提出的值时，会表现出很强的灵敏度变化。如所提出的，简化的分辨率方案导致焊道表面发展的良好估计。尽管如此，仍然有明显的差异与整个实验结果进行了讨论，并可以解释模型的局限性和知识不足的材料和界面性能。(C)2014爱思唯尔有限公司版权所有。
A new 3D finite element model, developed in a level set approach, is proposed to model hybrid gas metal arc/laser welding in multipass conditions. This heat and mass transfer model couples the resolution of the heat conservation equation, the momentum and mass conservation equations and the weld bead development. The arc welding total power is divided in two parts: one corresponding to the energy transferred to the fusion zone by droplets of melted filler material, the rest being transferred to the workpiece by the surrounding plasma. The droplets energy input is modelled as a volumetric heat source. Regarding the heat surface fluxes associated with plasma and laser heating, the "Continuum Surface Force" approach is used to model them as volumetric heat sources concentrated in the immediate neighbourhood of the metal gas interface. A resolution scheme, consisting in ignoring high velocity fluid flow in the fusion zone, through the use of an augmented liquid viscosity, is proposed and discussed. Accordingly, the liquid thermal conductivity is enhanced to result in a realistic heat transfer to the workpiece. The formation of the weld bead is obtained through the introduction of a source term in the mass conservation equation, and the application of the normal component of surface tension forces, proportional to the mean curvature of the metal gas interface. This approach is proposed to reduce computation time. The resolution scheme is applied to the simulation of hybrid welding of 18MND5 (ASME SA 533) steel grade. Results are compared to experimental measurements and observations operated in conditions close to industrial ones. The influence of the enhancement applied to the liquid conductivity coefficient is shown and discussed. A strong sensitivity evolution is demonstrated when varying it from the physical value to the value proposed in the welding literature. As proposed, the simplified resolution scheme leads to a good estimation of the weld bead surface development. Nevertheless, there are still noticeable differences with the whole set of experimental results that are discussed and can be explained by model limitations and insufficient knowledge of material and interfacial properties. (C) 2014 Elsevier B.V. All rights reserved.