| Summary: | 碩士 === 國立中山大學 === 機械工程研究所 === 86 === The goal of this thesis is to develop a simplifed and efficient approach to calculate the interlaminar stresses near the straight free edges in a composite laminate under uniaxial extension. It is well-known that in composite laminates the interlaminar stresses arise owing to the mismatch in elastic properties between plies especially at the free edges . When the magnitude of those stresses become large enough, delamination may occur in the edge region that will cause damage or initiate failure . So it is important to exactly estimate the laminate stresses in the consideration of so called boundary-layer effect or free edge effect . Based on the assumption of stress function proposed by the consideration of stress equilibrium equation, boundary conditions and traction continuity between plies, the present solution is generated by the minimization of the complementary energy of the whole laminate . In order to verify the feasibility and accurancy of our proposed three models and programs, the comparison with existing solutions of Graphite/Epoxy 4-ply laminates reported in the literature is made . In addition, the influence of material constitution, ratio of laminate width to thickness and fiber orientation on interlaminar stresses is also discussed . The results of the approximately numerical solutions exhibit excellent agreement with other numerical and analytical solutions available in the literature.The proposed models can significantly reduce the amount of computational work in the dertermination of interlaminar stresses, which are important on design work in the understanding of the stress distribution and the strength predicition for a laminate.
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