| Summary: | 碩士 === 中華大學 === 機械工程學系碩士班 === 96 === The nonlinear problem of large-deflection of a bossed and clamped layered isotropic circular plate under initial tension is studied. The approach extends the Von-Karman’s plate theory for large deflection to a symmetrically layered case with a center boss. The obtained nonlinear governing equations is reformulated in terms of lateral slope and radial force resultant by using a nondimesional technique. A finite difference method is then employed incorporating a numerical iteration scheme in solving the problem. For a 3-layered plate with nearly the same modulus and a very small center boss, the results correlate well with those available for a single-layer isotropic plate. The developed approach is then implemented for various initial tensions, and lateral pressures as well as different, and ratios between layer moduli.
Following the obtained numerical results, it is seen, the range of applied load and initial tension for the validity of linear solution is increased, as the size of the center boss becomes bigger. The influence of the lateral pressure decreases as the size of the center boss or the magnitude of initial tension is increased. Varying the boss size seems to have an apparent influence in the structural response, particularly in a lower initial tension condition. On the other hand, the influence due to difference in layer moduli appears to be insignificant. Moreover, the edge-zone effect of the plate tends to exasperates, as the lateral pressure and initial tension proceed or the size of the center boss increases.
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