| Co-Investigator(Kenkyū-buntansha) |
KAJIYAMA Mikio The University of Tokyo, Grad.Sch.of Agri.Life Sci., Assistant Professor, 大学院・農学生命科学研究科, 助手 (40191978)
TAKEMURA Akio The University of Tokyo, Grad.Sch.of Agri.Life Sci., Assistant Professor, 大学院・農学生命科学研究科, 助手 (50183455)
ONO Hirokuni The University of Tokyo, Grad.Sch.of Agri.Life Sci., Associate Professor, 大学院・農学生命科学研究科, 助教授 (30261960)
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| Research Abstract |
The three strain energy release rates, G_<IC>, G_<IIC>, and G_<IIIC>, of the adhesive joints corresponding to different deformation modes, namely, mode I,mode II and mode III,respectively, are their ability to resist crack propagation of solids in the adhesive layr. In this study, dependence of G_<IC>, G_<IIC> and G_<IIIC> on crack length were examined using the double-cantilever beam specimens by a compliance method, and the experimental conditions accorging to which G_<IC>, G_<IIC> and G_<IIIC> can be evaluated inrespective of the dimension of the specimen. The adhesive tensile strength and adhesive shear strength of the joints, where the same adhesives are used, were also measured. It was found that there is a positive correlation between the adhesive strength and square root of the strain eneygy release rete of the corresponding mode of deformation. However, thecorrelation coefficient was not necessarily high because a variety of commercially available adhesives were used in the first experiment. Then, in the next step of this study, some of the typical and well-defined adhesives were chosen, and again the strain energy release rates of the three different modes for the bonded wood specimens were evaluated, and at the same time the adhesive tensile strength and adhesive shear strength were measured. It was found that the rate-temperature superposition procedure can be applied to the strain energy release rates of the adhesive joints if they are measured as a function of both temperature and rates of deformation. Inaddition, there is a positive correlation between the adhesive shear strength and square root of the strain energy release rate of mode II in most cases, but the correlation between the adhesive tensile strength and square root of the strain energy release rate of mode I is expressed by a loop if the adhesive poiymer changes from the glassy state to the rubbery state within the temperature range of the experiments.
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