基于水平集方法的薄壁件堆焊成形数值分析

Numerical analysis of cladding forming in thin walled part based on level-set method

针对薄壁零件在微束等离子堆焊过程中的成形特点展开研究.采用有限元软件COMSOL对薄壁件堆焊层熔池进行温度场仿真,由于横截面散热条件较差,热累积明显,温度场分布呈现上"拱桥"下"水平"的特点.建立熔池自由表面变形的数学模型,采用水平集方法模拟熔池表面变形及凝固过程,并对影响熔池成形尺寸的因素进行探讨.结果表明,表面张力系数和接触角越大,熔池在宽度方向尺寸越小,高度方向尺寸越高.通过与试验焊缝对比,该模型能够较准确的反映薄壁零件单层堆焊的形貌特点.

The forming characteristics of cladding layer on thin-walled part under micro-beam plasma welding were studied.The finite element software COMSOL was used to simulate the temperature field of weld pool on thin-walled part. Since the heat dissipation in cross section was poor and the heat accumulation was significant,the temperature field distribution presented the characteristics of "arch"on top and "horizontal"at bottom. A mathematical model with free surface deformation of weld pool was established. The level-set method was applied to simulate the surface deformation and solidification of weld pool,and the influencing factors on the size of weld pool were discussed. The results showed that the larger the surface tension coefficient and the contact angle were,the smaller the size of molten pool in the width direction and the higher the size of molten pool in the height direction got. Compared with the test welded joint,the model can accurately reflect the forming characteristics of cladding on the thin-walled part.