Nuclear Techniques ›› 2019, Vol. 42 ›› Issue (7): 0-070604-9.doi: 10.11889/j.0253-3219.2019.hjs.42.070604

• NUCLEAR ENERGY SCIENCE AND ENGINEERING •    

Numerical simulation of residual stress in girth weld and failure stress analysis of reactor vessel

Liushuai LYU1,2,Xiaochun ZHANG1(),Bo SU1,2,Chaowen LI1,Naxiu WANG1   

  1. 1. Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China
    2. University of Chinese Academy of Sciences, Beijing 100049, China
  • Received:2018-09-27 Revised:2018-12-24 Online:2019-07-10 Published:2019-07-16
  • Contact: Xiaochun ZHANG E-mail:zhangxiaochun@sinap.ac.cn
  • About author:LYU Liushuai, male, born in 1992, graduated from Southwest Jiaotong University in 2015, master student, focusing on the structural integrity of nuclear reactor pressure vessels|LYU Liushuai, male, born in 1992, graduated from Southwest Jiaotong University in 2015, master student, focusing on the structural integrity of nuclear reactor pressure vessels
  • Supported by:
    Supported by Strategic Priority Research Program of Chinese Academy of Sciences(No.XDA02010000)

Abstract: Background

Residual stress in girth weld and failure stress of reactor vessel are very important in structural integrity assessment regardless the structural material.

Purpose

This study aims to evaluate the safety of internal surface cracks in welding parts of nickel-based alloy pressure vessels.

Methods

First of all, based on the British structural integrity assessment standard BS7910(2013), the failure assessment method of failure assessment diagram (FAD) was adopted, and the finite element analysis (FEA)

method

was employed to carry out numerical simulation of V groove and X groove multilayer and multiple girth butt welding of pressure vessel respectively. The distribution of welding residual stresses was then obtained. In addition, the residual stress curve of V groove butt welding was compared with that of BS7910(2013) standard. Secondly, the formula of BS7910(2013) 1-FAC curve was deduced. Finally, considering the influence of residual stress, stress concentration and plastic failure factor, the failure stress of semi-elliptic crack in the axial direction was predicted.

Results

The results show that the distribution of residual stress directly affects the calculation results. When the conditions remain unchanged, the calculation result of failure stress decreases with the increase of the ratio of crack depth (c) and crack half length (a). When c/a takes the same value, failure stress decreases with the increase of a.

Conclusions

The prediction method of welding residual stress and failure stress can provide some reference for the calculation of failure stress of pressure vessels and pipeline in the future.

Key words: Girth butt weld, Weld simulation, Residual stress, BS7910, FAD, Failure stress

CLC Number: 

  • TL3