Development of methods for prediction and control of welding stress and deformation besed on concept of inherent strain as their essential source

开发基于固有应变概念作为其基本来源的焊接应力和变形的预测和控制方法

基本信息

批准号：
03302037
负责人：
UEDA Yukio
金额：
$ 4.29万
依托单位：
Osaka University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Co-operative Research (A)
财政年份：
1991
资助国家：
日本
起止时间：
1991 至 1993
项目状态：
已结题

项目摘要

To promote the automation of shipbuilding process, the prediction and the control of the welding deformation are very important problems to be solved. Also, to achieve highly reliable estimation of the safety of ships against the fatigue damage, the quantitative estimation of welding residual stress is necessary. For establishing a consistent view on the welding residual stress and the deformation, the problem should be examined on the bases of the concept of inherent strain, which is considered to be the source of both the residual stress and the deformation. For the quantitative comparison to identify the most influential factor, numerical methods such as the FEM is a very powerful tool.Thus, a FEM code was developed in the first year of this research program for the prediction and the control of the welding deformation. The characteristics of the inherent strain and the residual stress were clarified. Further, the effects of tack welding pitch and the type of tab-plate are investigated based on the FEM simulation.In the following two years, the effects of root gap due to the cutting error and the residual stress in the steel plate are examined. Through this study, it is found that these factors are more influential than the tack weld and the tab. Thus, it is necessary to control them to reduce the welding deformation.To estimate the residual stress in butt weld and fillet weld with small number of measuring points, a new measuring method was developed and its validity was examined through experiments. The proposed method is based on the concept of inherent strain and the fact that the distribution of the inherent strain can be accurately described as a function involving small number of parameters.

为了促进造船过程的自动化，对焊接变形的预测和控制是要解决的非常重要的问题。同样，为了实现对船舶安全性抗疲劳损害的安全性的高度可靠估计，需要对焊接残余应力进行定量估计。为了对焊接应力和变形建立一致的看法，应在固有菌株概念的基础上检查问题，这被认为是残余应力和变形的来源。为了进行定量比较，要确定最有影响力的因素，数值方法（例如FEM）是一种非常强大的工具。因此，在该研究计划的第一年中，开发了一个fem代码，以预测和控制焊接变形。阐明了固有菌株和残余应力的特征。此外，根据FEM模拟研究了粘性焊接螺距和表板的类型。在接下来的两年中，检查了由于切割误差而引起的根间隙和钢板中的残留应力。通过这项研究，发现这些因素比钉焊缝和标签更具影响力。因此，有必要控制它们以减少焊接变形。要用少量测量点估算对接焊缝和圆角焊缝中的残余应力，则开发了一种新的测量方法，并通过实验检查了其有效性。所提出的方法基于固有应变的概念，并且可以将固有应变的分布准确地描述为涉及少量参数的函数。