1993 Fiscal Year Final Research Report Summary
Establishment of the method to evaluate the strength of adhesive joints and structures based on interfacial fracture mechanics
| Project/Area Number |
04452118
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
材料力学
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| Research Institution | University of Tokyo |
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Principal Investigator |
YUUKI Ryoji Institute of Industrial Science, University of Tokyo, Associate Professor, 生産技術研究所, 助教授 (70114709)
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| Co-Investigator(Kenkyū-buntansha) |
OHIRA Toshiaki Institute of Industrial Science, University of Tokyo, Research Associate, 生産技術研究所, 助手 (20092158)
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| Project Period (FY) |
1992 – 1993
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| Keywords | Adhesive Joint / Interface / Fracture Mechanics / Fatigue / Boundary Element Method / Elastic Analysis / Automobile Body / Stress Intensity Factor |
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| Research Abstract |
For the weight reduction and the improvement of the rigidity of an automobile body, the structural adhesive seems to be an useful technology. Recently adhesive joints or weldbonded joints are applied to some automobile bodies. It becomes to be very important to establish the method to evaluate the strength of adhesive joints or structure. The adhesives joint has interfaces between an adherend (steel) and adhesive and the stress becomes a singular at the edge of the interface. So a crack easily initiates at the edge and grows along the interface under cyclic loadings. Because of this stress singularity and interface crack in adhesive joints, the method to evaluate the strength of adhesive joints has not been established yet.
In this project, we carried out various fatigue tests of adhesive joints for an automobile body and the effects of various factors such as the plate thickness, type or size of specimens on the fatigue strength are clarified and constracted the date base of the fatigue strength of adhesive joints as well as spot welded joint and weldbonded joints of automobile body materials. And we also developed the method to analyze the stress intensity factor for an interface crack in the adhesive joint by using the boundary element method. It is found that that fatigue strengthes of adhesive joints with various plate thickness, adhesive thickness and types of specimens can be quantitatively evaluated by using the stress intensity factor for an interface crack and an interfacial fracture mechanics approach is very useful for the strength evaluation of adhesive joints.
We also propose the method to improve the fatigue strength of adhesive joints by means of dimples on the surface of the adherend.
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