Keywords: blast loading, laminated plate, large deflection, dynamic response, localised blast, nonlinear.

In engineering structures, the components made of laminated materials are often subjected to the dynamic loads such as air blast, shock, and impact. The blast, which is a time dependent load, causes the vibrations of the plate. These vibrations may result in the failure of the structures. Therefore, it is important to investigate the blast loaded vibrations. There are several studies on the effect of uniformly distributed air blast loading on the isotropic and laminated plates. However, few studies are reported on the localised blast effect [1,2].

In this study, the dynamic response of laminated plates subjected to the localised air blast loading is investigated. In-plane stiffness and inertia effects are considered when formulating the dynamic response of the laminated composite plate subjected to the localised blast loading. The geometric nonlinearity effects are also taken into account by using the von Kármán large deflection theory of thin plates. Transverse shear stresses are ignored. Approximate solution functions are assumed for the space domain and substituted into the equations of motion. Then, the Galerkin method is used to obtain the nonlinear differential equations in the time domain. The finite difference method is applied to solve the system of coupled nonlinear equations. The effect of the magnitude and localisation of the air blast load on the dynamic response is investigated. Both clamped and simply supported boundary conditions are analyzed. The displacement-time histories are obtained and compared with the ones obtained by using a commercial finite element code ANSYS. The displacement-time history of the plate center obtained by using the present method is found to be in an agreement with the finite element results for the simply supported plate. It is found that there is a small discrepancy between the displacement-time history of the plate center obtained by using the present method and the finite element method for the clamped plate. This can be the result of vibration modes with higher frequencies which could not be taken into account using only one term in the assumed function used in the theoretical method.

1

G.S. Langdon, S. Chung Kim Yuen, G.N. Nurick, "Experimental and numerical studies on the response of quadrangular stiffened plates. Part II: localised blast loading", International Journal of Impact Engineering, 31(1), 85-111, 2005. doi:10.1016/j.ijimpeng.2003.09.050

2

N. Jacob, S. Chung Kim Yuen, G.N. Nurick, D. Bonorchis, S.A. Desai, D. Tait, "Scaling aspects of quadrangular plates subjected to localised blast loads-experiments and predictions", International Journal of Impact Engineering, 30(8-9), 1179-1208, 2004. doi:10.1016/j.ijimpeng.2004.03.012

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