Stability Analysis of Laminated Soft Core Sandwich Plates Using Higher Order Zig-Zag Plate Theory

2015 ◽  
Vol 22 (11) ◽  
pp. 897-907 ◽  
Author(s):  
H. D. Chalak ◽  
Anupam Chakrabarti ◽  
Abdul Hamid Sheikh ◽  
Mohd. Ashraf Iqbal
Keyword(s):  
Stability Analysis ◽  
Plate Theory ◽  
Higher Order ◽  
Soft Core ◽  
Sandwich Plates

Enhanced First-Order Shear Deformation Theory for Laminated and Sandwich Plates

2005 ◽  
Vol 72 (6) ◽  
pp. 809-817 ◽  
Author(s):  
Jun-Sik Kim ◽  
Maenghyo Cho
Keyword(s):  
Shear Deformation ◽  
Deformation Theory ◽  
Plate Theory ◽  
Three Dimensional ◽  
Shear Deformation Theory ◽  
Higher Order ◽  
Laminated Plates ◽  
Sandwich Plates ◽  
First Order ◽  
Transverse Shear Strains

A new first-order shear deformation theory (FSDT) has been developed and verified for laminated plates and sandwich plates. Based on the definition of Reissener–Mindlin’s plate theory, the average transverse shear strains, which are constant through the thickness, are improved to vary through the thickness. It is assumed that the displacement and in-plane strain fields of FSDT can approximate, in an average sense, those of three-dimensional theory. Relationship between FSDT and three-dimensional theory has been systematically established in the averaged least-square sense. This relationship provides the closed-form recovering relations for three-dimensional variables expressed in terms of FSDT variables as well as the improved transverse shear strains. This paper makes two main contributions. First an enhanced first-order shear deformation theory (EFSDT) has been developed using an available higher-order plate theory. Second, it is shown that the displacement fields of any higher-order plate theories can be recovered by EFSDT variables. The present approach is applied to an efficient higher-order plate theory. Comparisons of deflection and stresses of the laminated plates and sandwich plates using present theory are made with the original FSDT and three-dimensional exact solutions.

Vibration characteristic of laminated sandwich plates with soft core based on an improved higher-order zigzag theory

2008 ◽  
Vol 222 (8) ◽  
pp. 1443-1452 ◽  
Author(s):  
M K Pandit ◽  
A H Sheikh ◽  
B N Singh
Keyword(s):  
Transverse Shear ◽  
Plate Theory ◽  
Three Dimensional ◽  
Higher Order ◽  
Thickness Variation ◽  
Shear Stresses ◽  
Sandwich Plates ◽  
Transverse Displacement ◽  
Zigzag Theory ◽  
Three Dimensional Elasticity

This paper presents an improved higher order zigzag theory for vibration of laminated sandwich plates. It ensures continuity of transverse shear stresses at all the layer interfaces and transverse shear stress-free condition at the top and bottom surfaces apart from core compressibility. The through-thickness variation of in-plane displacements is assumed to be cubic, whereas transverse displacement varies quadratically across the core, which is modelled as a three-dimensional elastic continuum. An efficient C0 finite element is developed for the implementation of the plate theory. The model is validated using three-dimensional elasticity solutions and some other relevant results available in the literature.

Free Vibration Analysis of Laminated Soft Core Sandwich Plates

2013 ◽  
Vol 135 (1) ◽  
Author(s):  
H. D. Chalak ◽  
Anupam Chakrabarti ◽  
Mohd. Ashraf Iqbal ◽  
Abdul Hamid Sheikh
Keyword(s):  
Finite Element ◽  
Free Vibration ◽  
Vibration Analysis ◽  
Plate Theory ◽  
Free Vibration Analysis ◽  
Soft Core ◽  
Sandwich Plates ◽  
Transverse Displacement ◽  
Fe Model ◽  
The Core

Free vibration behavior of laminated soft core sandwich plates with stiff laminated face sheets is investigated using a new C0 finite element (FE) model based on higher order zigzag theory (HOZT) in this paper. The in-plane displacement variations are considered to be cubic for both the face sheets and the core, while the transverse displacement is assumed to vary quadratically within the core and remains constant in the faces beyond the core. The plate theory ensures a shear stress-free condition at the top and bottom surfaces of the plate. Thus, the plate theory has all of the features required for an accurate modeling of laminated sandwich plates. As very few elements based on this plate theory (HOZT) exist and they possess certain disadvantages, an attempt has been made to develop this new element. The nodal field variables are chosen in such a manner to overcome the problem of continuity requirement of the derivatives of transverse displacements, i.e., no need to impose any penalty stiffness in the formulation. A nine node C0 quadratic plate finite element is implemented to model the HOZT for the present analysis. A new C0 element has been utilized to study some interesting problems on free vibration analysis of laminated sandwich plates. Many new results are also presented which should be useful for future research.

A higher order plate theory for dynamic stability analysis of delaminated composite plates

2000 ◽  
Vol 26 (3) ◽  
pp. 302-308 ◽  
Author(s):  
A. Chattopadhyay ◽  
A. G. Radu ◽  
D. Dragomir-Daescu
Keyword(s):  
Stability Analysis ◽  
Dynamic Stability ◽  
Plate Theory ◽  
Composite Plates ◽  
Higher Order

Delamination Effects in Circular Sandwich Plates With Laminated Faces of General Layup and a “Soft” Core

2001 ◽  
Author(s):  
Oded Rabinovitch ◽  
Yeoshua Frostig
Keyword(s):  
Sandwich Plate ◽  
Virtual Work ◽  
Plate Theory ◽  
Constitutive Relations ◽  
Solution Procedure ◽  
Theory Of Elasticity ◽  
Soft Core ◽  
Sandwich Plates ◽  
Field Equations ◽  
Circular Sandwich Plates

Abstract The present study is concerned with the behavior of delaminated circular sandwich plates with a compressible “soft” core and composite laminated face sheets of general layup. The analysis follows the concepts of the High-Order Sandwich Plate Theory and employs the variational principle of virtual work for the derivation of the field equations of the fully bonded and delaminated regions. In the penny shaped disbonded region, the delaminated faces can slip horizontally with respect one to another, yet they may be in contact and resist vertical normal compressive stresses. The compressible core is considered using the 3D theory of elasticity and the lamination theory is employed for the modeling of the composite laminated face sheets. The formulation yields coordinate-dependent constitutive relations and governing equations and the solution procedure adopts the Galerkin method in the circumferential direction and the multiple-points shooting method in the radial direction. Numerical results regarding a typical delaminated sandwich plate are presented in terms of deformations and stresses. The results reveal the effect of the anisotropic laminated face sheets on the response of the structure and the influence of the delamination on the overall and, especially, the localized behavior of the plate.

Buckling of laminated sandwich plates with soft core based on an improved higher order zigzag theory

2008 ◽  
Vol 46 (11) ◽  
pp. 1183-1191 ◽  
Author(s):  
M.K. Pandit ◽  
B.N. Singh ◽  
A.H. Sheikh
Keyword(s):  
Higher Order ◽  
Soft Core ◽  
Sandwich Plates ◽  
Zigzag Theory

A novel finite element formulation based on extended higher-order theory for sandwich plates of arbitrary aspect ratio

2020 ◽  
pp. 109963622097529
Author(s):  
Shehzaib Irfan ◽  
Faisal Siddiqui
Keyword(s):  
Finite Element ◽  
Aspect Ratio ◽  
Sandwich Plate ◽  
Plate Theory ◽  
Higher Order ◽  
Element Formulation ◽  
Sandwich Plates ◽  
Two Dimensional ◽  
Elasticity Solution ◽  
The Core

The extended higher-order sandwich plate theory for plates with arbitrary aspect ratio was formulated for two-dimensional orthotropic sandwich plates. The novelty of the theory is that it considers five generalized co-ordinates in the core (two axial and one transverse displacements at centroid of the core, one rotation at the centroid of the core about x-axis and one rotation at the centroid of the core about y-axis). Theory is very accurate when compared with the exact elasticity solution in terms of stresses and displacement both. In the current paper, a novel two dimensional rectangular element is developed based on the extended higher-order sandwich plate theory. Elemental equations along with the procedure to derive these is given in the paper. Developed finite element model is validated by comparing the results with elasticity solution and the theory itself for two sandwich plate configurations. The comparison shows that results obtained from the proposed finite element are in very good agreement with elasticity in terms of displacements and stresses both. Thus the proposed element is a powerful analysis tool which can be used for accurately analyzing the real world structures involving sandwich plates at a low computational cost.

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