Evaluation of fatigue strength in adhesively bonded joints under plate bending and proposal of fatigue design method

2022 Fiscal Year Final Research Report

• Project/Area Number: 21K20442
• Research Category: Grant-in-Aid for Research Activity Start-up
• Allocation Type: Multi-year Fund
• Review Section: 0303:Civil engineering, social systems engineering, safety engineering, disaster prevention engineering, and related fields
• Research Institution: Utsunomiya University
• Principal Investigator: THAY VISAL 宇都宮大学, 地域デザイン科学部, 助教 (90903667)
• Project Period (FY): 2021-08-30 – 2023-03-31
• Keywords: 接着接合部 / 疲労強度 / 疲労設計法 / 応力比 / 静的強度 / 主応力 / はく離 / 曲げ作用

Outline of Final Research Achievements

This research focuses on the establishment of repair or strengthening method of steel structures by externally bonded patch plates. The bending static tests and bending fatigue tests of adhesively bonded joints were conducted and the fatigue life is evaluated. The bending fatigue tests were conducted, varying the applied stress ranges and the stress ratio, the ratio of minimum and maximum stress of fatigue test. The result indicates that the fatigue life of adhesively bonded joints can be evaluated in the function of principal stress ratio, the ratio of principal stress range against principal stress at debonding by the bending test, with constant linearity regardless of the stress ratio.

Free Research Field

土木工学・構造工学・維持管理工学

Academic Significance and Societal Importance of the Research Achievements

本研究は，応力比に依存しない疲労強度の評価方法を提案する点にある．この提案した手法に基づいた接着接合部の疲労強度の評価方法を確立すれば，当て板接着工法による既設鋼構造物の補修・補強技術の開発・普及に貢献するだけでなく，構造物の維持管理の領域や自動車や航空機等の機械分野への応用の可能性も広がり，技術的なインパクトも高いと考える．