Composite Plates Research Papers - Academia.edu (original) (raw)

This paper examines the thermal instability of rectangular delaminated composite plates. A solution procedure is presented based on the third-order shear deformation theory by taking into consideration the von Karman geometrical... more

This paper examines the thermal instability of rectangular delaminated composite plates. A solution procedure is presented based on the third-order shear deformation theory by taking into consideration the von Karman geometrical nonlinearity. The proposed model is capable of analyzing both local buckling of the delaminated base laminate and sublaminate as well as the global buckling of the plate. The thermo-mechanical properties are temperature-dependent. The nonlinear equilibrium equations, derived by the minimum total potential energy principle, are solved by using the Ritz method along with the Newton– Raphson iterative procedure. Numerical results shed a light on the effects of embedded delamination, stacking sequences, and boundary conditions on the equilibrium path, thermal bifurcation points, buckling mode, in-plane displacement, normal/shear strain, and bending moment of the composite plates. It is found that the delamination leads to a substantial reduction in the thermal load-carrying capacity. Furthermore, depending on the boundary conditions and stacking sequence, the response of the perfect composite plates could be either of the bifurcation type or of the unique stable path.

This study is concerned with the aeroelastic behavior of a laminated composite rectangular plate with temperature dependent material properties. Plate equations for homogenous linear elastic material and small deformations are derived in... more

This study is concerned with the aeroelastic behavior of a laminated composite rectangular plate with temperature dependent
material properties. Plate equations for homogenous linear elastic material and small deformations are derived in the
frame of the Kirchhoff theory. Uniform and linear temperature distributions are considered on the layered composite plate
and it is assumed that the material properties of fiber and matrix vary with the temperature. The aerodynamic forces are
obtained by the piston theory. Equations of motion are derived in the variational form by the use of the Hamilton principle.
The Equations are solved using the finite element method. The laminated composite plates are discretized with the Semi
loof thin shell elements with eight nodes and a total of thirty-eight degrees of freedom. The free vibration results are in a
good agreement with the results of literature. The effects of aspect ratio, temperature distribution and lamination on the
flutter boundary have been examined. The flutter occurs at a high dynamic pressure for the plate with high aspect ratio. The
high temperatures on the plate results in a decrease of the flutter boundary. The number of laminate for a constant plate
thickness affects the flutter boundary until a certain laminate number.

Composite plates are to be made with Glass fiber –vinyl ester resin in 0/90 and +45/-45 orientations. After the impact damage, the composite plates are cut into strips of 20mm width. The tensile strengths of the composite strips are... more

Composite plates are to be made with Glass fiber –vinyl ester resin in 0/90 and +45/-45 orientations. After the impact damage, the composite plates are cut into strips of 20mm width. The tensile strengths of the composite strips are found. These are the residual tensile strengths. The residual strengths of the individual strips are predicted using the Tsai-Hill values. Tsai-Hill values have found to be a measure of the residual strength of the impact damaged plates.

The use of steel and fiber reinforced polymers (FRPs) for strengthening RC beams can significantly improve the flexural strength, fatigue life and the serviceability of the beams compared to un-strengthened beams. Prestressing materials... more

Fiber Reinforced Polymer (FRP) strengthening of structures has been gaining increasing interest, traditionally in application with concrete structures, and more recently in application with steel structures. Because of their unique blend... more

Fiber Reinforced Polymer (FRP) strengthening of structures has been gaining increasing interest, traditionally in application with concrete structures, and more recently in application with
steel structures. Because of their unique blend of properties, composites reinforced with high performance fibers find use in many structural applications. This paper defines the effect of FRP layers on behaviour of steel plate. In this regard, some models are selected and tested by rigid frame
and actuator. The experimental model is connected to a rigid frame.
The FRP layer acts similar to a lateral support for the steel plate, and possesses the intelligent behavior (specified control for establishing of flexural line and further leaning towards post buckling condition), meaning that the FRP layer can lead the local flexural deflection towards the total flexure
of the steel plate and effectively contributes more in resisting the shear stresses and extension of post flexure lines in steel plate and formation of composite plate. This is due to involvement of more area of steel plate to resisting of the imposed stresses. Result shows, the FRP layers would increase the stiffness, energy absorption, shear capacity and will be decreasing the ductility of steel plate as compared with composited steel plate with other materials as reinforcement concrete.

This paper is devoted to the buckling analysis of thin composite plates under straight single-walled carbon nanotubes reinforcement with uniform distribution and random orientations. In order to develop the fundamental equations, the... more

This paper is devoted to the buckling analysis of thin composite plates under straight single-walled carbon nanotubes reinforcement with uniform distribution and random orientations. In order to develop the fundamental equations, the B3-Spline finite strip method along with the classical plate theory (CPT) is employed and the total potential energy is minimized which leads to an eigenvalue problem. For deriving the effective modulus of thin composite plates reinforced with carbon nanotubes, the Mori-Tanaka method is used in which each straight carbon nanotube is modeled as a fiber with transversely isotropic elastic properties. The numerical results including the critical buckling loads for rectangular thin composite plates reinforced by carbon nanotubes with various boundary conditions and different volume fractions of nanotubes are provided and the positive effect of using carbon nanotubes reinforcement in buckling of thin plates is illustrated.

Analysis of the laminated composite plates under transverse loading is considered using the new method of Isogeometric Analysis (IGA). Non-Uniform Rational B-Splines (NURBS) are used as shape functions for modelling the geometry of the... more

Analysis of the laminated composite plates under transverse loading is considered using the new method of Isogeometric Analysis (IGA). Non-Uniform Rational B-Splines (NURBS) are used as shape functions for modelling the geometry of the structure and are also used as shape functions in the analysis process. Boundary conditions are imposed using a kind of collocation method. To show robustness of the new technique, some examples are represented and are compared with the element free Galerkin and theoretical method at the end. The obtained results show the efficiency of the method. The optimization process is done using genetic algorithm method.

The detection of delaminations in composite structures due to impacts is a critical issue for any structural health monitoring (SHM) programme. In this work, an experimental campaign is carried out to investigate the presence of... more

The detection of delaminations in composite structures due to impacts is a critical issue for any structural health monitoring (SHM) programme. In this work, an experimental campaign is carried out to investigate the presence of delamination induced in carbon-fibre-reinforced-plastic (CFRP) plates by low velocity impacts (LVI). A reduced number of piezoelectric devices for actuation and sensing purposes are employed. The proposed study starts with the choice of the proper positions of the piezoelectric sensor and actuator through the analysis of the numerical curvature mode shapes of the composite laminated plate. A wavelet packet transform (WPT)-based algorithm is applied on the vibrating response of the plates to extract wavelet-based damage sensitive features. Linear Discriminant Analysis (LDA) is then applied on the extracted damage sensitive features to enhance the performance of the proposed delam-ination identification procedure. Results show the effectiveness of the developed SHM routine when a reduced number of sensors is either desirable or mandatory.

A computational model was developed to simulate and predict failure response of fibrous composite panels subjected to drop-weight impact on un-partitioned fibrous composite panels using finite element analysis. The mathematical... more

A computational model was developed to simulate and predict failure response of fibrous composite panels subjected to drop-weight impact on un-partitioned fibrous composite panels using finite element analysis. The mathematical formulation consisting ...