Prediction of Brittle Fracture from Defects Considering Cyclic History Effects and Ductile Crack Growth: Estimation Method of Accumulated Plastic Deformation Capacity

2018 Fiscal Year Final Research Report

• Project/Area Number: 16K06598
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Building structures/Materials
• Research Institution: Ariake National College of Technology
• Principal Investigator: Iwashita Tsutomu 有明工業高等専門学校, 創造工学科, 教授 (10332090)
• Research Collaborator: Azuma Koji
• Project Period (FY): 2016-04-01 – 2019-03-31
• Keywords: 脆性破壊 / 塑性変形能力 / ワイブル応力 / 繰返し負荷 / 累積損傷度 / 延性き裂

Outline of Final Research Achievements

This research showed a brittle fracture prediction method that could estimate the plastic deformation capacity of notched steel specimens with a ductile crack under cyclic loading. Brittle fracture occurred from notches which were subjected to both compression and tension and the method predicted brittle fracture under the condition. The research outcome is related to prediction and prevention of brittle fracture with ductile crack growth from notches and defects at welded connections in steel structures subjected to an earthquake loading.

Free Research Field

鋼構造

Academic Significance and Societal Importance of the Research Achievements

本研究では，繰返し載荷を受ける切欠き付鋼試験片から延性き裂を伴って発生する脆い破壊現象である脆性破壊を予測することで，試験片の持つ変形能力を推定できることを示した．切欠きに圧縮・引張の繰返し負荷が与えられる条件での脆性破壊予測を示した点に学術的意義がある．本研究の成果は，地震動により鋼構造溶接接合部に生じ得る欠陥や切欠き等から延性き裂を伴って発生する脆性破壊を予測・防止につながる．