摘要： 以安全端异种金属焊接接头为代表的核电关键焊接结构环境致裂已成为影响压水堆长期安全运行的关键问题。研究表明，焊接接头扩展裂纹尖端区域的高温水环境、材料和力学因素是决定焊接结构材料环境致裂扩展速率的决定因素。为了准确了解力学性能不均匀性和残余应力场共存条件下的焊接接头扩展裂纹尖端的力学参量，本研究巧妙地利用弹塑性有限元方法，建立了扩展裂纹尖端局部应力分析方法、焊接接头残余应力场建立方法，以及焊接接头不均匀材料力学性能的表征方法。 本文研究结果为准确分析焊接接头环境致裂扩展裂纹尖端的力学参量，以及准确评价核电关键焊接结构材料环境致裂扩展速率提供了一种新的分析方法。

　　关键词：焊接接头，环境致裂，扩展裂纹，力学场，数值模拟

 Numerical Simulation Of Mechanical Field At Tip Of Environmentally Assisted Cracking In Welded Joints Of Nuclear Power Plant
Xue He^*,  Gong Xiaoyan ^*
* (School of Mechanical Engineering, Xi’an University of Science and Technology, Xi’an, 710054, China)

　　Abstract:Environmentally assisted cracking （EAC） in welded components, such as the safe-end dissimilar metal welded joints, is a critical issue affecting the long-term operation and safety of pressurized water reactor in nuclear power plants. Researches indicate that the aqueous environment, material and mechanical factors at the tip of growing crack are the critical factors of the EAC growing rate in welded structural materials. To understand the mechanical factors at the growing crack tip in welded joint with the mechanical heterogeneity and the residual stress in detail, the local stress analysis approach at the growing crack tip, the applied mode of the welded residual stress field and the definition means of welded mechanical heterogeneity are established in this study. The results provide a new approach for analyzing the mechanical factors at the EAC tip and accurately evaluating the EAC growth rate of welded structural materials in nuclear power plant

　　Key words:welded joint, environmentally assisted cracking, growing crack, mechanical field, numerical simulation

　　联系方式

　　薛何：xue_he@hotmail.com