基于ANSYS的船舶复杂结构焊接变形预测研究

Research of Complicated Ship Structure Welding Distortion Based on ANSYS

运用通用有限元软件ANSYS对LNG船304L不锈钢液舱及大型复杂耐压舱结构采用组合焊道和不同类型单元混合使用的等效简化,建立了三维有限元模型。在不影响计算精度的前提下,采取了一系列减少计算量和增强收敛的措施,成功地解决了热弹塑性有限元分析计算量大、收敛困难等问题,完成了大型复杂结构多道焊的热弹塑性有限元分析和预测结构的焊接变形。在不锈钢液舱简化模型中随着焊接道数的增加,变形越来越接近实际焊接变形,Y方向最大变形量减小趋势变缓,其最大下塌量小于4.22mm,复杂耐压舱结构的计算结果表明在结构刚度小的部位施加合适的支撑能有效减小结构的焊接变形,为焊接变形的控制提供了可靠的理论依据。

The weld process of large complicated structure is computed with general FEM software ANSYS and the welding distortion is obtained.Welding distortion to large complicated structure is analysed with thermal elastic-plastic FEM.Different kinds of elements and predigesting structure,which did not influence the calculation accuracy,is adopted.Based on the premise of heat equivalency effect,the weld process is predigested by the use of combinatorial multi-beads to reduce the number of bead.The distortion is analysed and the measures to decrease the distortion are put forward.Then welding distortion analysis of large complicated structure is achieved with thermal elastic-plastic FEM.In the simplified model of stainless steel tank,with the increase in the number of welding road,the deformation is more and more close to the actual welding distortion.Meanwhile the reduces of maximum deformation of direction y trends to be slowed,and its maximum collapse is less than 4.22mm.The research results provid a good theoritical basis for the control of welding distortion of the complex pressure cabin structure.