爆炸消除焊接残余应力的数值模拟

Numerical simulation on the relief of welding residual stress through and explosive treatment

焊接残余应力及其控制技术是重大工程结构物(例如反应堆、潜艇等)建造中关注的核心问题之一。爆炸法消除残余应力是近年来发展起来的高效、低成本的1种新技术,但对其机理的研究仍然相当缺乏。本文利用非线性有限元软件ABAQUS对爆炸消除焊接残余应力技术进行了数值模拟,同时考察了焊缝中夹杂的裂纹缺陷对爆炸载荷的响应。研究对象为70 mm厚的超厚钢板对接焊缝,焊接坡口为X型。本文主要完成了以下2项研究工作。1)将盲孔法测得的焊接残余应力分布预置到模型中,计算了爆炸载荷作用下不同布药方式时焊接残余应力的再分布,并将其与对应的实测结果进行比较。研究结果表明,金属材料的塑性流动是爆炸消除焊接残余应力的根本因素。2)在模型的焊缝区引入面状裂纹来表征焊缝中的凝固裂纹,利用ABAQUS用户自定义子程序开发的基于虚拟裂纹闭合法的三维断裂单元,计算能量释放率对爆炸载荷的响应。研究结果表明,爆炸载荷并不一定会导致裂纹的扩展。因此,本文的研究方法和结果对于爆炸消除焊接残余应力在工程应用领域具有指导意义。

Welding residual stress and its control is the construction of major engineering structures（such as reactors,submarines,etc.）of the core issue of concern.Explosive method for relieving residual stress is a new technology developed in recent years by high efficiency and low-cost,but its principle is still quite a lack of research.In this paper,we use nonlinear finite element software ABAQUS for the numerical simulation on the relief of welding residual stress through an explosive treatment,and also investigate the cracks in the weld bead of the response to the explosion.The subject is 70mm thick,low carbon steel plate with butt welds,and its weld joint is the X-type.We complete the following two studies.1） Distributed welding residual stress what is measured by the blind-hole method into the FEA model,calculate redistribution of welding residual stress through the explosive loading of different dynamite distribution modes and compare the response with the corresponding experimental results.The results show that the plastic flow of metal material is fundamental factors on the relief of welding residual stress through an explosive treatment.2） we characterize the planar crack in the weld bead of the model as the welding solidification crack,and use ABAQUS user subroutine to develop three-dimensional fracture element based on virtual crack closure technique,calculate the strain energy release rate response to blast loading.The results show that the explosion does not necessarily lead to crack propagation.Therefore,the research method and results for the explosion to relieve welding residual stress have significance in the field of engineering applications.