Evaluation of fatigue strength of adhesively bonded joints considering stress ratio

考虑应力比的粘接接头疲劳强度评估

• 批准号: 22K14314
• 负责人: THAY VISAL
• 金额: $ 2.83万
• 依托单位: Utsunomiya University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Early-Career Scientists
• 财政年份: 2022
• 资助国家: 日本
• 起止时间: 2022-04-01 至 2025-03-31
• 项目状态: 未结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-22K14314/
• 关键词: 接着接合部; 疲労強度; 疲労設計法; 応力比; 静的強度; 接着端部; 応力緩和

接着接合部には，高いせん断応力と接着面に対して垂直応力が同時に生じるため，疲労限度を超えると，その端部からはく離が進展する．当て板接着工法による補修・補強を行う場合には，当て板端部のはく離を予防する対策が求められ，定量的な評価方法も必要である．本研究では，接着接合部の静的強度，接着接合部の疲労強度を実験的・解析的に検討し，接着接合の疲労強度を一般化し，接着接合部の設計法を提案する．さらに，接着接合部のはく離強度の向上を目的として，接着接合の端部形状を検討し，適用範囲を拡大する．令和４年度は，次年度の静的試験と疲労試験を実施するため，以下の３つの項目で検討を行った．（１）静的試験による実験データを蓄積し，静的強度の破壊包絡線の評価方法を完成させる．静的曲げ試験を行い，当て板端部のはく離の起点とその静的強度を検証した．（２）接着接合部の端部形状の検討では，まず，有限要素解析により，接着剤中に生じる力の流れと接着端部の応力状態を明らかにし，応力緩和を確認した．（３）振動型疲労試験機を導入し，共振現象などを避けるために，予備疲労実験を行い，疲労試験体の寸法を決定した．（４）接着接合部の疲労強度の評価では，振動型疲労試験機による曲げ疲労試験を行い，疲労強度を確認する．次に，有限要素解析により，はく離をモデル化して，はく離先端の応力拡大係数を算定し，線形破壊力学に基づいてはく離の進展解析を行った．

The joint part is high and the vertical force is high. The joint part is high and the vertical force is high. The joint part is high and the vertical force is high. In case of repair and reinforcement of plate joining method, it is necessary to evaluate the quantitative evaluation method when the separation of plate end is prevented. In this study, the static strength of the joint, the fatigue strength of the joint, and the design method of the joint are proposed. In addition, the strength of the joint part is increased, and the shape of the joint end is discussed. In the fourth year, the following three projects were discussed. (1) The static test results are accumulated, and the static intensity and the evaluation method of the breaking envelope are completed. The static curve test is carried out in the middle of the test, and when the plate end is separated from the starting point and the static strength is verified. (2) The analysis of the shape of the end of the joint part is not clear, the finite element analysis is not clear, the flow of the force generated in the joint part is clear, and the relaxation of the force is confirmed. (3) Vibration fatigue test machine is introduced, resonance phenomenon is avoided, fatigue test method is determined. (4) Next, the fatigue strength of the joint shall be evaluated, and the fatigue strength shall be confirmed in the vibration fatigue test machine. Second, finite element analysis, separation, separation, separation.