熱疲労荷重下における亀甲状き裂の発生要因と影響

概要

論文の詳細を見る
In nuclear power plants, the crack networks caused by thermal fatigue loading are shallow and do not penetrate the wall thickness. Mechanical interaction between the cracks and stress gradient in the depth direction are thought to suppress crack growth. In this study, in order to investigate the influence of the shape of the crack network on cracking behavior, finite element analyses were conducted using a three-dimensional model of the crack network under thermal fatigue loading. A Monte Carlo simulation of the initiation and growth of cracks was carried out to simulate the evolution of the crack network. It was revealed that the crack network can develop under a bi-axial stress field together with significant stress gradient and that the mechnical interaction between cracks reduces the crack growth rate in the depth direction. It was concluded that a well-developed crack network in an operating plant is observed only when the crack growth in the depth direction is interrupted and the structural integrity of cracked components is assured.
社団法人日本機械学会の論文
2009-03-25