Prediction of ductile crack growth and initiation of brittle fracture from weld defects - Quality control criterion of the welded connection

2015 Fiscal Year Final Research Report

• Project/Area Number: 25420600
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Building structures/Materials
• Research Institution: Sojo University
• Principal Investigator: AZUMA Koji 崇城大学, 工学部, 教授 (80320414)
• Co-Investigator(Kenkyū-buntansha): IWASHITA Tsutomu 有明工業高等専門学校, 建築学科, 准教授 (10332090)
• Project Period (FY): 2013-04-01 – 2016-03-31
• Keywords: 脆性破壊 / 延性き裂 / 溶接欠陥 / 破壊靭性 / 塑性拘束 / 機械切欠き / 有限要素解析 / 破壊評価

Outline of Final Research Achievements

This paper concerns the applicability of the Weibull stress approach for prediction of brittle fracture initiated at the root of welds. Beam-to-diaphragm joint models, which were designed to represent a connection of an I-section beam to RHS column member with through diaphragms, were tested under cyclic loads. Complete joint penetration groove welds were used for the connection between the beam flange and the diaphragm. Specimens had those discontinuities at the roots of welds to the diaphragm, which were created by inserting copper plates into the grooves before welding, or by using wire electrical discharge machining (EDM). Through cracks or surface cracks were installed on both sides of weld terminations.
The prediction of brittle fracture with a variety of defect sizes by using the FE analysis was conducted. The applicability of the Weibull stress approach, comparing it with the applicability of the TSM approach, in predicting brittle fracture from such defects was verified.

Free Research Field

建築構造・材料