Stress Analysis of Sandwich Plates With Unidirectional Thickness Variation

1986 ◽  
Vol 53 (3) ◽  
pp. 609-613 ◽  
Author(s):  
N. Paydar ◽  
C. Libove
Keyword(s):  
Cross Sections ◽  
Transverse Shear ◽  
Middle Surface ◽  
Thickness Variation ◽  
Sandwich Plates ◽  
The Core ◽  
Small Deflection ◽  
The Face ◽  
Deflection Theory ◽  
Sheet Membrane

A small deflection theory is presented for the stresses and deformations in variable thickness elastic sandwich plates that are symmetric about a middle surface. In this analysis the face sheets are treated as membranes; the core is assumed to be inextensible in the thickness direction, to carry only transverse shear stress on its cross sections normal to middle surface, and to be deformable in transverse shear. The theory takes into account the contribution of the face sheet membrane forces (by virtue of their slopes) to the transverse shear.

Bending of Sandwich Plates of Variable Thickness

1988 ◽  
Vol 55 (2) ◽  
pp. 419-424 ◽  
Author(s):  
N. Paydar ◽  
C. Libove
Keyword(s):  
Potential Energy ◽  
Variable Thickness ◽  
Middle Surface ◽  
Total Potential Energy ◽  
Sandwich Plates ◽  
Energy Principle ◽  
Total Potential ◽  
Small Deflection ◽  
The Face ◽  
Deflection Theory

A small deflection theory, consisting of differential equations and a total potential energy expression, is presented for determining the stresses and deformations in variable thickness elastic sandwich plates symmetric about a middle surface. The theory takes into account the contribution of the face-sheet membrane forces (by virtue of their slopes) to the transverse shear. A finite-difference formulation of the stationary total potential energy principle is presented along with an illustrative application.

On the Torsion of Rectangular Sandwich Plates

1956 ◽  
Vol 23 (2) ◽  
pp. 191-194
Author(s):  
Paul Seide
Keyword(s):  
Cross Sections ◽  
Torsional Rigidity ◽  
Constant Thickness ◽  
Sandwich Plates ◽  
The Core ◽  
Equal Thickness ◽  
Rectangular Sandwich Plates

Abstract The torsional rigidity of rectangular sandwich plates of constant thickness is calculated, with cross sections assumed free to warp. The faces are isotropic and of equal thickness while the core may be orthotropic, the axes of orthotropy coinciding with co-ordinate axes of the structure.

Buckling of Circular Plate on Elastic Foundation

1965 ◽  
Vol 87 (3) ◽  
pp. 323-324 ◽  
Author(s):  
L. V. Kline ◽  
J. O. Hancock
Keyword(s):  
Circular Plate ◽  
Middle Surface ◽  
Elastic Plates ◽  
Buckling Loads ◽  
Simply Supported ◽  
Small Deflection ◽  
Edge Conditions ◽  
Deflection Theory ◽  
Plate On Elastic Foundation ◽  
Clamped Edge

The buckling loads are found for the simply supported and clamped-edge conditions for a circular plate on a springy foundation under the action of edge loading in the middle surface of the plate. The small deflection theory of bending of thin elastic plates has been used.

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.

An Accurate Discrete Model for the Dynamics of Web-Core Sandwich Plates

2015 ◽  
Author(s):  
Anup Pydah
Keyword(s):  
Discrete Model ◽  
Vibrational Frequency ◽  
Transverse Shear Deformation ◽  
Sandwich Plates ◽  
Lateral Bending ◽  
One Dimensional ◽  
Simply Supported ◽  
The Core ◽  
Transverse Bending ◽  
The Face

An accurate discrete model is presented here for the dynamics of simply supported web-core sandwich plates using the elasticity approach. By modelling the face-plates as 3D solids and the core webs using a plane stress idealization for transverse bending and classical one-dimensional models for lateral bending and torsion, the non-classical effects of transverse shear deformation, thickness-stretch and rotary inertia are completely accounted for in both, the face-plates and webs. Vibrational frequency results obtained using this model are used to highlight the errors of the commonly used model based on the classical Kirchhoff hypothesis for the face-plates, indicating the importance of using refined theories for modelling the face-plates.

The Strain-Energy Expression for Thin Elastic Shells

1958 ◽  
Vol 25 (4) ◽  
pp. 546-552
Author(s):  
J. H. Haywood ◽  
L. B. Wilson
Keyword(s):  
Circular Cylinder ◽  
Plane Stress ◽  
Strain Energy ◽  
Middle Surface ◽  
Thin Shells ◽  
Elastic Shells ◽  
Energy Expression ◽  
Small Deflection ◽  
Deflection Theory

Abstract A strain-energy expression is derived for thin isotropic elastic shells in terms of the displacements of the middle surface of the shell. This expression is confined to small-deflection theory, and the condition of plane stress previously used in the theory of thin shells is retained. A simplified expression is also obtained by the introduction of the Kirchhoff-Love hypothesis, and the relative merits of these two expressions are discussed. The strain-energy expression is applied to the thin circular cylinder, and the result is compared with various strain-energy expressions developed by previous authors.

On the Sandwich Plate Twist Test for Shear Testing

2008 ◽  
Author(s):  
F. Avile´s ◽  
L. A. Carlsson
Keyword(s):  
Shear Deformation ◽  
Correction Factor ◽  
Transverse Shear ◽  
Plate Theory ◽  
Transverse Shear Deformation ◽  
Element Analysis ◽  
Shear Correction Factor ◽  
The Core ◽  
The Face ◽  
Data Reduction Method

This work examines the viability of the sandwich twist (anticlastic) test as a means to determine the in-plane and transverse shear properties of the face sheets and core in sandwich materials through analysis and testing. The contribution of core transverse shear to the total compliance of the specimen is quantified for different material systems and the adequacy of classical laminated plate theory (CLPT) as a data reduction method for such a test is examined. Parametric studies are conducted using finite element analysis (FEA) to examine the influence of transverse shear deformation on the plate compliance and propose some guidelines for specimen design. It is shown that CLPT greatly underestimates the plate compliance, except when very stiff cores and compliant face sheets are used, as a result of transverse core shear deformation. A shear correction factor is proposed to correct the CLPT compliance for transverse shear deformation of the core. For sandwich panels with compliant cores, the shear correction factor may be used to determine transverse shear modulus of the core.

scholarly journals Stability of cylindrical panel with variable thickness

2006 ◽  
Vol 28 (1) ◽  
pp. 56-65 ◽  
Author(s):  
Nguyen Thi Hien Luong ◽  
Thach Som So Hoach
Keyword(s):  
Variable Thickness ◽  
Shell Thickness ◽  
Cylindrical Panel ◽  
Thickness Variation ◽  
Simply Supported ◽  
Small Deflection ◽  
Linear Buckling ◽  
Variation Parameter ◽  
Deflection Theory ◽  
Linear Buckling Analysis

A linear buckling analysis based on the small deflection theory is presented for the cylindrical panel with sinusoidal changes in the shell thickness. The buckling load for simply supported cylindrical panel around the periphery is defined by using the hybrid perturbation - Galerkin method. The influence of the thickness variation parameter on the critical loads is investigated.

Material Selection for CFRP-Aluminium-Foam-Sandwiches Manufactured by a PUR Spraying Process

2017 ◽  
Vol 742 ◽  
pp. 317-324
Author(s):  
Peter Rupp ◽  
Peter Elsner ◽  
Kay André Weidenmann
Keyword(s):  
Manufacturing Process ◽  
Sandwich Structures ◽  
Bending Stiffness ◽  
Effective Density ◽  
Sandwich Composites ◽  
Open Cell ◽  
The Core ◽  
Bending Modulus ◽  
The Face ◽  
Spraying Process

Sandwich structures are ideal for planar parts which require a high bending stiffness ata low weight. Usually, sandwich structures are manufactured using a joining step, connecting theface sheets with the core. The PUR spraying process allows to include the infiltration of the facesheet fibres, the curing of the matrix and the joining of the face sheets to the core within one processstep. Furthermore, this manufacturing process allows for the use of open cell core structures withoutinfiltrating the core, which enables a comparison of different material configurations, assembled bythe same manufacturing process. The selection of these materials, with the aim of the lowest possiblemass of the sandwich composite at a constant bending stiffness, is displayed systematically within thiswork.It could be shown that the bending modulus calculated from the component properties matched theexperimentally achieved values well, with only few exceptions. The optimum of the bending modulus,the face sheet thickness and the resulting effective density could be calculated and also matched theexperimental values well. The mass-specific bending stiffness of the sandwich composites with corestructures of open cell aluminium foams was higher than with closed cell aluminium foams, but wasexceeded by sandwich composites with Nomex honeycomb cores.

A C0 three-node triangular element based on preprocessing approach for thick sandwich plates

2017 ◽  
Vol 21 (6) ◽  
pp. 1820-1842
Author(s):  
Wu Zhen ◽  
Ma Rui ◽  
Chen Wanji
Keyword(s):  
Transverse Shear ◽  
Equilibrium Equation ◽  
Three Dimensional ◽  
Higher Order ◽  
Triangular Element ◽  
Shear Stresses ◽  
Sandwich Plates ◽  
Transverse Shear Stress ◽  
Transverse Shear Stresses ◽  
Derivatives Of

This paper will try to overcome two difficulties encountered by the C0 three-node triangular element based on the displacement-based higher-order models. They are (i) transverse shear stresses computed from constitutive equations vanish at the clamped edges, and (ii) it is difficult to accurately produce the transverse shear stresses even using the integration of the three-dimensional equilibrium equation. Invalidation of the equilibrium equation approach ought to attribute to the higher-order derivations of displacement parameters involved in transverse shear stress components after integrating three-dimensional equilibrium equation. Thus, the higher-order derivatives of displacement parameters will be taken out from transverse shear stress field by using the three-field Hu–Washizu variational principle before the finite element procedure is implemented. Therefore, such method is named as the preprocessing method for transverse shear stresses in present work. Because the higher-order derivatives of displacement parameters have been eliminated, a C0 three-node triangular element based on the higher-order zig-zag theory can be presented by using the linear interpolation function. Performance of the proposed element is numerically evaluated by analyzing multilayered sandwich plates with different loading conditions, lamination sequences, material constants and boundary conditions, and it can be found that the present model works well in the finite element framework.

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