焊接应力场与应变场的计算与讨论

经典的观点认为焊缝存在残余压缩塑性应变,而目前有学者认为焊缝是在冷却的过程中形成的,与加热过程无关,认为焊缝只存在拉伸塑性应变,而不存在压缩塑性应变.针对这一对传统残余塑变理论的质疑,采用有限元方法对薄板熔焊对接接头纵向应力和应变的瞬态变化以及由焊缝中心到母材边缘的纵向应力和应变分布情况进行了计算.结果表明,焊缝及近缝区存在着残余压缩塑性应变,应力状态为拉应力,由焊缝中心到母材边缘其纵向应力由拉应力转变为压应力,纵向压缩塑性变形量逐渐下降,离焊缝较远受温度场影响较小的母材不产生塑性变形.

Calculation and discussion of welding stress and strain field

Residual compressive plastic strain presents in the weld from traditional views, now some literates think that weld is formed during the cooling process which isn'' t concerned with the heating process.Therefore, they concluded that not the compressive plastic strain but the tensile plastic strain presents in the weld, in order to indicate the mechanism of the formation of welding residual stress and strain, welding longitudinal stress and plastic strain of the low-carbon steel are simulated by finite element method.The simulated results show that residual compressive plastic strain and tensile stress are found in the weld longitudinal plastic strain decreasing from the weld centre to the edge of the base metal where plustic deformation won'' t take place.