Sedat Süsler

The Nonlinear Dynamic Behaviour of Tapered Laminated Plates Subjected to Blast Loading

In this study, the geometrically nonlinear dynamic behaviour of simply supported tapered laminated composite plates subjected to the air blast loading is investigated numerically. In-plane stiffness, inertia and the geometric nonlinearity effects are considered in the formulation of the problem. The equations of motion for the tapered laminated 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. Then, the Galerkin method is used to obtain the nonlinear algebraic differential equations in the time domain. The resulting equations are solved by using the finite difference approximation over the time. The effects of the taper ratio, the stacking sequence and thefiberorientation angleon thedynamic response areinvestigated. Thedisplacement-timeand strain-time histories are obtained on certain points in the tapered direction. The results obtained by using the present method are compared with the ones obtained by using a commercial finite element software ANSYS. The results are found to be in an agreement. The method presented here is able to determine the nonlinear dynamic response of simply supported tapered laminated plates to the air blast loading accurately.

Dynamic behaviour of laminated plates subjected to thermomechanical loads

Abstract. The engineering structures may be subjected to the dynamic loads such as blast. Therefore, in the design of such structures, the effect of the blast loading should be taken into account. There are two possible effects of the blast: sudden pressure and the temperature rise. In this study, a closed form solution is presented for the thermomechanical transient analysis of the simply supported laminated composite plates subjected to blast loading. 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 taken into account by using the von Karman large deflection theory of thin plates. 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 and strain-time histories are obtained for critical cases and compared the isothermal condition. The method presented here can be used for the dynamic response analysis of laminated plates in preliminary design.

Design and Manufacturing of a Composite Drive Shaft

In this study, a composite drive shaft for heavy commercial vehicles is designed and manufactured. The carbon/epoxy composite material is used for the shaft tube and the end joints are made of steel. The material properties of the carbon/epoxy composite are obtained by performing coupon tests. The shaft tube is modeled using ANSYS finite element software. The static, buckling and modal analysis are achieved to obtain the Tsai-Wu strength ratio, the critical buckling torque and free vibration frequencies, respectively. The shaft tube is manufactured by using filament winding method. The steel end connections are bonded to the shaft tube during the filament winding process.

An experimentally validated numerical method for investigating the air blast response of basalt composite plates

ABSTRACT Nonlinear air blast response of basalt composite plates is analysed by using a generalized differential quadrature (GDQ) method, which requires less solution time and decreases the complexity compared to finite element method. A test environment that contains a shock tube is designed and set to experiment on the transient response of blast loaded laminated plates. Experimental and numerical results show a good agreement in terms of displacement, strain, and acceleration versus time. The responses of glass/epoxy, Kevlar/epoxy, and carbon/epoxy composite plates are also investigated by using GDQ method and the results are compared with the basalt/epoxy composite plate and discussed.

Dynamic behaviour of laminated plates subjected to a combined loading

The engineering structures may be subjected to the dynamic loads such as blast. Therefore, in the design of such structures, the effect of the blast loading should be taken into account. Several studies are reported on both free vibration and dynamic response analysis of isotropic, orthotropic and laminated composite plates subjected to air blast loading. In all these studies, only the effect of the blast is taken into account. However, because of the initial situation, in-plane forces may exist and may affect the dynamic response of the plate subjected to the blast loading. In this study, a closed form solution is presented for the simply supported laminated composite plates subjected to a combined loading case which includes both the blast and the in-plane forces. 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 taken into account by using the von Kármán large deflection theory of thin plates. 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 and strain-time histories are obtained for different combined loading configurations.