• Earthquakes and Structures
• /
• v.11 no.1
• /
• pp.63-82
• /
• 2016

In this study, the bending and dynamic behaviors of laminated composite plates is examined by using a refined shear deformation theory and developed for a bending analysis of orthotropic laminated composite plates under various boundary conditions. The displacement field of the present theory is chosen based on nonlinear variations in the in-plane displacements through the thickness of the plate. By dividing the transverse displacement into the bending and shear parts and making further assumptions, the number of unknowns and equations of motion of the present theory is reduced and hence makes them simple to use. In the analysis, the equation of motion for simply supported thick laminated rectangular plates is obtained through the use of Hamilton's principle. Numerical results for the bending and dynamic behaviors of antisymmetric cross-ply laminated plate under various boundary conditions are presented. The validity of the present solution is demonstrated by comparison with solutions available in the literature. Numerical results show that the present theory can archive accuracy comparable to the existing higher order shear deformation theories that contain more number of unknowns.

• Journal of the Korean Society for Advanced Composite Structures
• /
• v.1 no.2
• /
• pp.1-13
• /
• 2010

Delamination reduces an elastic buckling load of the laminated composite structures and lead to global structural failure at loads below the design level. Therefore, the problem of the delamination buckling of laminated composite structures has generated significant research interest and has been the subject of many theoretical and experimental investigations. However, questions still remain regarding a complete understanding and details of the phenomena involved. In this paper an efficient finite element model is presented for analyzing the elastic buckling behavior of laminated composite plates with square embedded delamination using a solid element based on a three-dimensional theory. The solid finite element, named by EAS-SOLID8, based on an enhanced assumed strain method is developed. The study for elastic buckling behavior of laminated composite plates with embedded square delaminations are focused on various parameters, such as support condition and width-to-thickness ratio. Both graphs and buckling modes in this paper are good guide for design of the laminated composite plates with embedded square delamination.

• Steel and Composite Structures
• /
• v.17 no.3
• /
• pp.321-338
• /
• 2014

In the present study, a new simple first-order shear deformation theory is presented for laminated composite plates. Moreover, the number of unknowns of this theory is the least one comparing with the traditional first-order and the other higher-order shear deformation theories. Equations of motion and boundary conditions are derived from Hamilton's principle. Analytical solutions of simply supported antisymmetric cross-ply and angle-ply laminates are obtained and the results are compared with the exact three-dimensional (3D) solutions and those predicted by existing theories. It can be concluded that the proposed theory is accurate and simple in solving the static bending and free vibration behaviors of laminated composite plates.

• Journal of Korean Association for Spatial Structures
• /
• v.11 no.3
• /
• pp.77-83
• /
• 2011

Laminated composite plates have shown their superiority over metals in applications requiring high specific strength, high specific modulus, and so on. Therefore, they have used in various industry. However, they have poor resistance to impact compared to typical metal materials. To resolve this problem by many researchers for a variety of studies have been attempted. This study investigates characteristic of impact behavior of laminated composite plates due to initial stress. Using finite element program which involved the indentation law, we investigate characteristic of impact behavior of laminated composite plates due to initial stress.

• Steel and Composite Structures
• /
• v.39 no.2
• /
• pp.149-158
• /
• 2021

In this research paper, the free vibrational response of laminated composite plates is investigated using a non-polynomial refined shear deformation theory (NP-RSDT). The most interesting feature of this theory is the parabolic distribution of transverse shear deformations while ensuring the conditions of nullity of shear stresses at the free surfaces of the plate without requiring the Shear correction factor "Ks". A fourth-nodded isoparametric element with four degrees of freedom per node is employed for laminated composite plates. The numerical analysis of simply supported square anti-symmetric cross-ply and angle-ply laminated plate is carried out using a special discretization based on four-node finite element method which four degrees of freedom per node. Several numerical results are presented to show the effect of the coupling parameters of the plate such as the modulus ratios, the thickness ratio and the plate layers number on adimensional eigen frequencies. All numerical results presented using the current finite element method (FEM) is presented in 3D curve form.

• Journal of Aerospace System Engineering
• /
• v.16 no.5
• /
• pp.35-42
• /
• 2022

This paper deals with predicting comparable mechanical properties of laminated composite plates. The stiffness of an equivalent anisotropic composite plate is derived based on classical lamination theory. A novel failure criterion is defined to describe the failure behaviour of laminated composite plates based on micro-mechanics failure criteria. Finally, the theory's validation of finite element analysis results was verified. We concluded that this theory is very suitable for failure analysis of laminated composite plates for aerospace applications due to their relative simplicity and computational efficiency.

• Steel and Composite Structures
• /
• v.17 no.1
• /
• pp.69-81
• /
• 2014

The novelty of this paper is the use of trigonometric four variable plate theory for free vibration analysis of laminated rectangular plate supporting a localized patch mass. By dividing the transverse displacement into bending and shear parts, the number of unknowns and governing equations of the present theory is reduced, and hence, makes it simple to use. The Hamilton's Principle, using trigonometric shear deformation theory, is applied to simply support rectangular plates. Numerical examples are presented to show the effects of geometrical parameters such as aspect ratio of the plate, size and location of the patch mass on natural frequencies of laminated composite plates. It can be concluded that the proposed theory is accurate and simple in solving the free vibration behavior of laminated rectangular plate supporting a localized patch mass.

• Journal of Korean Society of Steel Construction
• /
• v.24 no.4
• /
• pp.399-410
• /
• 2012

In this study, vibration tests are performed on cantilevered and clamped-clamped laminated composite rectangular plates using experimental modal analysis technique. The damages are simulated by applying progressive line cracks to the laminated composite plates for damage evaluations due to crack growth. The changes of frequency response functions(FRFs), MAC values, and modal parameters (frequency, mode shape and damping ratio) of the damaged composite plates, which are obtained by the modal testing of impact hammer, are investigated. Each experimental modal parameter of the progressively damaged composite plates is compared with natural frequencies and mode shapes obtained by finite element analysis. It is seen that the damage can be evaluated from the changes in the geometric properties and structural behaviors of the laminated composite plates resulting from the model updating process of the finite element model as a benchmark.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 1997.04a
• /
• pp.486-490
• /
• 1997

Composite materials have varios complicated characteristics to the ply materials, ply orientations, ply stacking sequences and boundary conditions. Therefore, it is difficult to analysis composite materials. For efficient use of composite materials in engineering applications the dynamic behavior, that is, natural frequencies, nodal patterns should be informed. This study presents the experimental and FEM results for the free vibration of symmetrically and antisymmetrically laminated composite and hybrid composite rectangular plates. In order to demonstrate the validity of the experiment, FEM analysis using ANSYS was performed and natural frequencies experimentally obtined is compared with that calculated by FEM analysis. The results obtained from both experiment and FEM analysis show a good agreement.

• Advanced Composite Materials
• /
• v.16 no.1
• /
• pp.63-81
• /
• 2007

Based on the Kirchhoff hypothesis of normal-remain-normal, the present work analyses piezoelectric laminated plates, wherein poled piezoelectric laminae are transversely isotropic and function as actuators. A quadric electric field is induced inside a piezoelectric lamina under a given applied voltage and mechanical bending. The governing equations for the piezoelectric laminated plate derived from the principle of virtual work in terms of the electric enthalpy have the same forms as those for a conventional composite laminated plate. We use rectangular sandwich plates of Al/PZT/Al and PZT/Al/PZT with four simply supported edges to demonstrate the prediction of the maximum bending stress in the PZT layer. The analytic solutions are verified by three-dimensional finite element analysis.