Nonlinear dynamic analysis of tapered sandwich plates with multi-layered faces subjected to air blast loading
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Nonlinear dynamic analysis of tapered sandwich plates with multi-layered faces subjected to air blast loading Sedat Su¨sler . Halit S. Tu¨rkmen . Zafer Kazancı
Received: 5 January 2016 / Accepted: 27 May 2016 Springer Science+Business Media Dordrecht 2016
Abstract The nonlinear dynamic behavior of simply supported tapered sandwich plates subjected to air blast loading is investigated theoretically and numerically. The plate is supposed to have both tapered core and tapered laminated face sheets and be subjected to uniform air blast load. The theory is based on a sandwich plate theory, which includes von Ka´rma´n large deformation effects, in-plane stiffnesses, inertias and shear deformations. The sandwich plate theory for plates with constant thickness which have one-layered face sheets found in the literature is developed to analyze the tapered sandwich plates with multilayered face sheets. The equations of motion are derived by the use of the virtual work principle. Approximate solution functions are assumed for the space domain and substituted into the equations. 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 tapered sandwich plate subjected to air blast load is also modelled by using the finite element method. The displacement– time and strain–time histories are obtained. The S. Su¨sler H. S. Tu¨rkmen (&) Faculty of Aeronautics and Astronautics, Istanbul Technical University, Maslak, Istanbul 34469, Turkey e-mail: [email protected] Z. Kazancı Aerospace Engineering Department, Turkish Air Force Academy, Yesilyurt, Istanbul 34149, Turkey
theoretical results are compared with finite element results and are found to be in an agreement. Keywords Tapered sandwich plate Air blast load Large deflection Nonlinear analysis Variable thickness
1 Introduction A sandwich structure is a class of composite material which is manufactured by attaching two thin laminated stiff faces to a core which is lighter and less stiff. They have the capability of specific bending stiffness, so they are called bending dominant structures in industry (Jeon and Hong 1992). Sandwich structures have a wide application area in aerospace, defense and marine industry. Sandwich and laminated composite components such as panels can have variable thickness in some cases while the others have constant thickness according to design, geometric necessities and minimum weight requirements. As an example for an application area, sandwich structures with variable thickness are used for wing skin panels and helicopter rotor blades by taking the airfoil shapes because of aerodynamic concerns. Thus, the thickness varies along the chord line from the leading edge to the trailing edge (Jeon and Hong 1992; Pinckney 1973). A tapered effect in thickness can be sometimes sufficient to obtain the variable thickness. For
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example, tapered sandwich panels with two faces with constant thick
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