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.

A New Theory of Elastic Sandwich Plates—One-Dimensional Case

1959 ◽  
Vol 26 (3) ◽  
pp. 415-421
Author(s):  
Yi-Yuan Yu
Keyword(s):  
Infinite Plate ◽  
Theory Of Elasticity ◽  
Dimensional Case ◽  
Transverse Shear Deformation ◽  
Sandwich Plates ◽  
Rotatory Inertia ◽  
One Dimensional ◽  
The Core ◽  
The One ◽  
Final Equation

Abstract A new flexural theory of isotropic elastic sandwich plates is deduced from the theory of elasticity. The one-dimensional case is presented in this paper. The theory includes the effects of transverse-shear deformation and rotatory inertia in both the core and faces of the sandwich, and no limitation is imposed upon the magnitudes of the ratios between the thicknesses, material densities, and elastic constants of the core and faces of the sandwich. The method used is an extension of one due to Mindlin [1], and the results reduce to those of his for the corresponding homogeneous plates as special limiting cases. A final equation also may be simplified and reduced to the corresponding results of Reissner [2], Hoff [3], and Eringen [4] for the bending of ordinary sandwich plates that have thin faces. Results of the theory are applied to the problem of bending of a cantilever plate subjected to load at the unsupported end and to the problem of propagation of straight-crested waves in an infinite plate.

Accurate analytical solutions for shear-deformable web-core sandwich plates

2016 ◽  
Vol 19 (5) ◽  
pp. 616-643 ◽  
Author(s):  
Anup Pydah ◽  
K Bhaskar
Keyword(s):  
Analytical Solutions ◽  
Plate Theory ◽  
Three Dimensional ◽  
Sandwich Plates ◽  
Lateral Bending ◽  
Classical Plate Theory ◽  
Transverse Bending ◽  
The Face ◽  
Three Dimensional Elasticity ◽  
Shear Deformable

An accurate discrete model and analytical solutions thereof are presented for shear-deformable web-core sandwich plates. The face-plates are analyzed using the equations of three-dimensional elasticity, while the webs are accurately modelled using the classical plate theory with a plane stress solution for transverse bending and a Levy-type methodology for lateral bending. It is shown that this obviates the need for a complete three-dimensional analysis of the sandwich plate. Results obtained by this approach are used to highlight the effect of shear deformation of the face-plates.

Nonlinear, Damped Vibrations of Sandwich Plates With Time-Dependent Temperature

1993 ◽  
Author(s):  
S. Lukasiewicz ◽  
Z. Q. Xia
Keyword(s):  
Sandwich Plate ◽  
Rapid Change ◽  
Time Dependent ◽  
Viscoelastic Damping ◽  
Sandwich Plates ◽  
Simply Supported ◽  
Geometrical Nonlinearities ◽  
The Core

Abstract The paper studies the effect of the rapid change of temperature on the vibrations of simply supported sandwich plates. It has been taken into consideration that the properties of the facings and of the core of the sandwich plate materials change with the change of the temperature. The effects of the viscoelastic damping and geometrical nonlinearities on the behaviour of the plate have also been included. It was found that the rapid change of temperature affects the amplitude and frequency of the vibrations.

Evaluation of Thermal Stresses in Sandwich Panels with Chiral Cellular Cores

2014 ◽  
Vol 601 ◽  
pp. 242-245
Author(s):  
Stefan Sorohan ◽  
Dan Mihai Constantinescu ◽  
Marin Sandu ◽  
Adriana Sandu
Keyword(s):  
Sandwich Panel ◽  
Thermal Stresses ◽  
Sandwich Panels ◽  
Linear Variation ◽  
Simply Supported ◽  
Stationary Temperature Field ◽  
The Core ◽  
The Face ◽  
Composite Face ◽  
Moduli Of Elasticity

Sandwich panels are important components of advanced structures used in aerospace, automotive, railway, civil engineering etc. They are subjected to high and repeated variations of temperature which induce additional stresses as the core and the face sheets are from different materials having different coefficients of thermal expansion and moduli of elasticity. Therefore it is important to evaluate both mechanical and thermal stresses. In the literature one can find thermo-mechanical analyses of sandwich panels with metallic or composite face sheets and having a honeycomb or compact core made from polyurethane foam. In this paper was analysed a plane sandwich panel made from a cellular rigid polyurethane core, having a chiral configuration and auxetic properties (negative Poissons ratio) exposed to a stationary temperature field with a linear variation from +25 °C on one sheet to-50 °C on the opposite sheet. Two boundary conditions were considered in the thermo-mechanical evaluation: the free panel and the panel simply supported around the edges.

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.

Dynamical Response of Sandwich Plates with Strength Graded Cores to Blast Loading

2011 ◽  
Vol 410 ◽  
pp. 317-320
Author(s):  
B. Yu ◽  
Feng Xian Xin ◽  
T.J. Lu
Keyword(s):  
Influence Factor ◽  
Dynamical Response ◽  
Sandwich Plates ◽  
Gradient Distribution ◽  
One Dimensional ◽  
The Core ◽  
Analytical Scheme ◽  
Shock Impact ◽  
Underwater Blast ◽  
Strength Gradient

A one-dimensional analytical scheme is developed for the dynamical response of sandwich plates having strength graded cores to shock impact. Results for in-air blast show that strength gradient distribution affects significantly the dynamic behavior of the sandwich. With fluid-structure interaction (FSI) taken into account, the approach is extended to underwater blast. It is demonstrated that whilst the influence of strength gradient distribution is noticeable on the impulse resistance, it depends strongly upon the core strength and FSI index. A gradient influence factor (GIF) is introduced to quantify the influence of different strength gradient distributions.

Transverse Bending of Cross-Ply Laminated Circular Cylindrical Plates

1976 ◽  
Vol 18 (2) ◽  
pp. 53-56 ◽  
Author(s):  
P. K. Sinha ◽  
A. K. Rath
Keyword(s):  
Aspect Ratio ◽  
Transverse Shear ◽  
Shallow Shell ◽  
Shell Theory ◽  
Plate Theory ◽  
Transverse Shear Deformation ◽  
Laminated Plate ◽  
Simply Supported ◽  
Transverse Bending ◽  
Plate Curvature

The paper deals with the transverse bending of simply supported, circular, cylindrical plates consisting of cross-ply laminates with arbitrary sequences of 0° and 90° plies. The analysis is carried out within the framework of laminated-plate theory and shallow-shell theory, where the effect of transverse shear deformation is considered. The non-dimensional deflection parameters are computed for panels consisting of antisymmetric graphite-epoxy plies. The influence of the coupling between bending and extension, the plate curvature and the aspect ratio are studied and discussed.

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.

Characterization of the vibration, stability and static responses of graphene-reinforced sandwich plates under mechanical and thermal loadings using the refined shear deformation plate theory

2021 ◽  
pp. 109963622199386
Author(s):  
Hessameddin Yaghoobi ◽  
Farid Taheri
Keyword(s):  
Shear Deformation ◽  
Volume Fraction ◽  
Plate Theory ◽  
Micromechanical Model ◽  
Sheet Thickness ◽  
Analytical Investigation ◽  
Sandwich Plates ◽  
Simply Supported ◽  
Vibration Stability ◽  
Shear Deformation Plate Theory

An analytical investigation was carried out to assess the free vibration, buckling and deformation responses of simply-supported sandwich plates. The plates constructed with graphene-reinforced polymer composite (GRPC) face sheets and are subjected to mechanical and thermal loadings while being simply-supported or resting on different types of elastic foundation. The temperature-dependent material properties of the face sheets are estimated by employing the modified Halpin-Tsai micromechanical model. The governing differential equations of the system are established based on the refined shear deformation plate theory and solved analytically using the Navier method. The validation of the formulation is carried out through comparisons of the calculated natural frequencies, thermal buckling capacities and maximum deflections of the sandwich plates with those evaluated by the available solutions in the literature. Numerical case studies are considered to examine the influences of the core to face sheet thickness ratio, temperature variation, Winkler- and Pasternak-types foundation, as well as the volume fraction of graphene on the response of the plates. It will be explicitly demonstrated that the vibration, stability and deflection responses of the sandwich plates become significantly affected by the aforementioned parameters.

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.

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