β Scribed by N. Hu; H. Fukunaga; M. Kameyama; Y. Aramaki; F.K. Chang
No coin nor oath required. For personal study only.
In order to analyze the vibration response of delaminated composite plates of moderate thickness, a FEM model based on a simple higher-order plate theory, which can satisfy the zero transverse shear strain condition on the top and bottom surfaces of plates, has been proposed in this paper. To set up a C 0 -type FEM model, two artiΓΏcial variables have been introduced in the displacement ΓΏeld to avoid the higher-order derivatives in the higher-order plate theory. The corresponding constraint conditions from the two artiΓΏcial variables have been enforced e ectively through the penalty function method using the reduced integration scheme within the element area. Furthermore, the implementation of displacement continuity conditions at the delamination front has been described using the present FEM theory. Various examples studied in many previous researches have been employed to verify the justiΓΏcation, accuracy and e ciency of the present FEM model. The in uences of delamination on the vibration characteristic of composite laminates have been investigated. Especially the variation of 'curvature of vibration mode' (i.e., the second-order di erential of de ections in vibration mode) caused by delamination has been studied in detail to provide valuable information for the possible identiΓΏcation of delamination. Furthermore, two approaches have been investigated to detect a delamination in laminates by employing this information.
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