| Budget Amount *help |
¥2,200,000 (Direct Cost: ¥2,200,000)
Fiscal Year 1998: ¥300,000 (Direct Cost: ¥300,000)
Fiscal Year 1997: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1996: ¥1,400,000 (Direct Cost: ¥1,400,000)
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| Research Abstract |
At first, we investigated the mechanical properties and strength of interface between fibers and plastics by using three type specimens, pull-out specimen, tensile strength specimen and shear strength specimen. Pull-out strength was the largest, however, shear strength was low and a third of the pull-out strength and tensile strength was the middle level of the two type strength. By using the strength data obtained experimentally, we tried to analyze the strength of interface numerically. Hybrid method which included finite element method and boundary element method was applied to clear the macroscopic strength of the interface of fibers and plastics. As a result, it was shown that the hybrid method was useful to simulate the step by step crack propagation at the interface and the cohesive strength was estimated macroscopic point of view. Secondary, microscopic research about the strength of interface between fibers and plastics was made by using molecular dynamics (MD) method to clarify the mechanics of strength at the interface. Carbon fiber reinforced plastics (epoxy resin) was studied, where carbon fibers were modeled by C-C chain and resin structure was modeled as micro gel chains. Bridging effect was studied by MD analysis, it was shown that the strength increased as increasing bridging rate. In order to show the influence of coarseness of interface, well-type fiber model was used, and it was shown that the shear type strength increased as increasing rate of coarseness.
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