Yunjae Kim
Korea University · 工学
研究室紹介
Professor Yunjae Kim's research lab specializes in the structural integrity and failure assessment of nuclear pressure boundary components, with a strong focus on fracture mechanics, residual stress analysis, and plastic limit load estimation for components with geometric and material discontinuities. The lab conducts advanced finite element analyses to predict failure strength, J-integral values, and residual stresses in critical components such as pipes, nozzles, elbows, and dissimilar metal welds—particularly those involving alloy 82/182 in nuclear power plants. Their work emphasizes developing practical, closed-form solutions and reference stress-based methods for engineering applications, ensuring safety and reliability under complex loading and environmental conditions.
Research Overview
Research Output Trend
Figures are computed from collected data and may differ slightly.
Selected Papers
15This paper proposes a new method to estimate failure strength of a pipe with local wall thinning. The method is based on the equivalent stress averaged over the minimum ligament in the locally wall thinned region. The highlight of the proposed method is to propose a simple scheme to estimate the equivalent stress in the minimum ligament. Inspired by the reference stress method for approximate creep stress analysis, approximate estimation equations are proposed for the equivalent stress in the mi
In nuclear power plants, ferritic low alloy steel components were connected with austenitic stainless steel piping system through alloy 82/182 butt weld. There have been incidents recently where cracking has been observed in the dissimilar metal weld. Alloy 82/182 is susceptible to primary water stress corrosion cracking. Weld-induced residual stress is main factor for crack growth. Therefore exact estimation of residual stress is important for reliable operating. This paper presents residual st
In nuclear power plants, ferritic low alloy steel nozzle was connected with austenitic stainless steel piping system through alloy 82/182 butt weld. Accurate estimation of residual stress for weldment is important in the sense that alloy 82/182 is susceptible to stress corrosion cracking. There are many results which predict residual stress distribution for alloy 82/182 weld between nozzle and pipe. However, nozzle and piping system usually connected through safe end which has short length. In t
This paper provides net-section limit pressures and a reference stress based J estimation method for pipes with internal axial surface cracks under internal pressure. Based on systematic small strain FE limit analyses using elastic-perfectly plastic materials, closed-form approximations of net-section limit pressures are presented. Then, based on proposed net-section limit moments, a method to estimate elastic-plastic J is proposed based on the reference stress approach. Comparison with extensiv