Session: MF-22-01 3D Crack Growth Simulation Using FEA

Paper Number: 123083

123083 - Development of a Program Based on Re-Meshing for Natural Crack Growth of Multiple Cracks 

Nuclear power plant (NPP) facilities undergo periodic in-service inspections (ISI) for structural integrity assessment. During these inspections, if multiple cracks are detected, the stress distribution and fracture mechanics parameters at the crack tips can be significantly influenced by adjacent cracks. Therefore, to accurately simulate multiple crack evaluation and crack growth, it's essential to consider such crack interactions. Existing criteria and standards (ASME Sec. XI, API RP 579, and BS7910) provide guidelines for evaluating and coalescing multiple cracks. However, these conventional procedures may assume conservative evaluations, such as merging two close elliptical cracks into a single larger ellipse.

In this study, a program based on re-meshing finite element analysis was developed that includes crack-tip meshes suitable for multiple cracks. Multiple cracks were implanted into various structures, including flat plates and pipes. Parameters such as crack depth, crack length, and the distance between cracks were adjusted to simulate the growth of multiple cracks, and an analysis of crack interactions was conducted. Based on this analysis, improved criteria were proposed that more realistically address multiple crack interactions, growth, and coalescence. These improved criteria were then benchmarked against current standards to ensure their accuracy and relevance. Consequently, the study provides insights that enhance the understanding and precise evaluation of intricate crack interactions.

Presenting Author: Gi-Bum Lee Seoul National University of Science and Technology

Presenting Author Biography: Gi-Bum Lee is currently a PhD student at Seoul National University of Science and Technology. His research focuses on understanding and predicting the failure and crack growth of structure. Gi-Bum Lee primarily provides engineering solutions for the safety and reliability of structures through finite element analysis.

Authors:

Gi-Bum Lee Seoul National University of Science and Technology
Chan-Gi Hong Seoul National University of Science and Technology
Seok-Jun Yoon Seoul National University of Science and Technology
Nam-Su Huh Seoul National University of Science and Technology
Sung-Hoon Park VENG Co., Ltd.