Prediction of brittle fracture initiatedtoeast growing from weld defectsofductile cracks

• Project/Area Number: 22560579
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Building structures/materials
• Research Institution: Sojo University
• Principal Investigator: AZUMA Koji 崇城大学, 工学部, 准教授 (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): 2010 – 2012
• Project Status: Completed (Fiscal Year 2012)
• Budget Amount: ¥4,420,000 (Direct Cost: ¥3,400,000、Indirect Cost: ¥1,020,000); Fiscal Year 2012: ¥1,560,000 (Direct Cost: ¥1,200,000、Indirect Cost: ¥360,000); Fiscal Year 2011: ¥1,170,000 (Direct Cost: ¥900,000、Indirect Cost: ¥270,000); Fiscal Year 2010: ¥1,690,000 (Direct Cost: ¥1,300,000、Indirect Cost: ¥390,000)
• Keywords: 鋼構造 / 柱梁接合部 / 脆性破壊 / 溶接欠陥 / 塑性拘束 / 建築構造・材料 / 溶接接合部 / 破壊予測 / 延性亀裂 / 表面欠陥 / 破壊靱性 / 有限要素解析 / 破壊評価 / 表面亀裂

Research Abstract

Welded plate bend models, which were designed to represent a connection of anI-section beam to an RHS column member with through diaphragms, were tested under cyclic loads in order to investigate the correlation of defect size, dimensions and quantity of ductile crack growth. Test results supported prediction; brittle fracture occurred from tips of defects. It was attempted to predict the fracture moment. The predicted moments using J values which were taken into account plastic constraint of crack tips roughly coincide with the test results.

Research Products

• [Journal Article] 欠陥を有する完全溶込み溶接始終端部から発生する脆性破壊塑性拘束が及ぼす影響 (2012)
  • Author(s): 岩下勉,東康二
  • Journal Title: 日本建築学会構造系論文集 Volume: 77 Pages: 105-112
  • NAID: 130004508109
  • Peer Reviewed
• [Journal Article] Effect ofPlastic Constraint on Brittle Fracture inSteel: Evaluation Using Toughness Scaling Model (2012)
  • Author(s): Iwashita, T. and Azuma, K.
  • Journal Title: Journal of Structural Engineering, ASC Volume: 138 Issue: 6 Pages: 744-752
  • DOI: 10.1061/(asce)st.1943-541x.0000507
  • Peer Reviewed
• [Journal Article] Further experimental study on assessment of safety of beam-column connections with weld defects from brittle fracture (2012)
  • Author(s): Azuma, K. and Iwashita, T.
  • Journal Title: Tubular Structures Volume: XIV Pages: 351-358
  • Peer Reviewed
• [Journal Article] 欠陥を有する完全溶込み溶接始終端部から発生する脆性破壊塑性拘束が及ぼす影響 (2011)
  • Author(s): 岩下勉, 東康二
  • Journal Title: 日本建築学会構造系論文集 Volume: 77 Pages: 105-112
  • NAID: 130004508109
  • Peer Reviewed
• [Journal Article] Assessment of brittle fracture from defects using toughness scaling model (2010)
  • Author(s): Iwashita, T., Azuma, K
  • Journal Title: Procs, 11th International Symposium on Tubular Structures Volume: ISTS XIII Pages: 515-522
  • Peer Reviewed
• [Presentation] Assessment of brittle fracture for single edge notched bend specimens with different machined-notch depth (2013)
  • Author(s): Iwashita, T., Kobayashi, R. and Azuma,K.
  • Organizer: 32ndInt. Conf. on Ocean, Offshore and Arctic Engineering
  • Place of Presentation: Nantes, France
  • Year and Date: 2013-06-11
• [Presentation] Furtherexperimental study on assessment of safety of beam-column connections with weld defects from brittle fracture (2012)
  • Author(s): Azuma, K. and Iwashita, T.
  • Organizer: Symposium on Tubular Structures
  • Place of Presentation: London, UK
  • Year and Date: 2012-09-12
• [Presentation] 異なる深さの機械切欠きを有する3点曲げ試験片の脆性破壊に関する研究-ワイブル応力による検討- (2012)
  • Author(s): 小林良平, 岩下勉, 東康二
  • Organizer: 日本建築学会九州支部
  • Place of Presentation: 北九州市
  • Year and Date: 2012-03-04
• [Presentation] Brittle fracture of single edge notched bend specimens with different machined-notch depth (2012)
  • Author(s): Kobayashi, R., Iwashita, T. and Azuma, K.
  • Organizer: International Symposium on Technology for Sustainability,
  • Place of Presentation: Bangkok, Thailand
• [Presentation] 溶接始終端の表面欠陥を起点とする脆性破壊の数値シミュレーション
  • Author(s): 坂本高穂，東康二，岩下勉
  • Organizer: 日本建築学会九州支部
  • Place of Presentation: 大分