Keywords: blast loading, tapered plate, large deflection, dynamic response, taper ratio, nonlinear.

Tapered plates are important components of many engineering structures. Several studies have been reported on the free vibration analysis of isotropic and orthotropic tapered plates [1]. Some studies are also reported on the dynamic response of plates subjected to the blast loading [2,3]. However, few studies have reported on the response of tapered plates subjected to air blast loading.

In this study, the dynamic behavior of tapered isotropic and orthotropic plates subjected to the air blast loading is investigated numerically. In-plane stiffness and inertia effects are considered in the formulation of the problem and transverse shear stresses are ignored. The geometric nonlinearity effects are also taken into account by using the von Kármán large deflection theory of thin plates. The equations of motion for the plate are derived by the use of the virtual work principle. Approximate solution functions are assumed for the space domain and substituted into the equations of motion. 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 displacement-time histories are obtained.

The theoretical results are compared with ANSYS finite element results. It is shown that there is an agreement between the displacement-time histories predicted using both methods. The shift between the displacement-time histories predicted using theoretical and numerical methods can be the result of vibration modes with higher frequencies which could not be taken into account using only two terms in the assumption function used in theoretical method. The free vibration frequencies of the clamped plate are higher than those of the simply supported plate, as expected.

A parametric study is conducted considering the effect of taper ratio by using theoretical method and ANSYS. While the taper ratio of the plate increases, the amplitude of the displacement decreases for the simply supported plate. However, for the clamped plate, increasing the taper ratio did not effect the displacement amplitude, significantly.

This study can be extended to the analysis of the plates with parabolically changing taper ratios subjected to different type of dynamic loads. The effect of the character of the blast pressure on the dynamic behavior can also be investigated.

1

P. Malekzadeh, "Nonlinear free vibration of tapered Mindlin plates with edges elastically restrained against rotation using DQM", Thin-Walled Structures, 46, 11-26, 2008. doi:10.1016/j.tws.2007.08.016

2

H.S. Türkmen, Z. Mecitoglu, "Nonlinear structural response of laminated composite plates subjected to blast loading", AIAA Journal, 37(12), 1639-1647, 1999. doi:10.2514/2.646

3

Z. Kazanci, Z. Mecitoglu, "Nonlinear damped vibrations of a laminated composite plate subjected to blast load", AIAA Journal, 44(9), 2002-2008, 2006. doi:10.2514/1.17620

purchase the full-text of this paper (price £20)

go to the previous paper
go to the next paper
return to the table of contents
return to the book description
purchase this book (price £145 +P&P)