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.

Forced Flexural Vibrations of Sandwich Plates in Plane Strain

1960 ◽  
Vol 27 (3) ◽  
pp. 535-540 ◽  
Author(s):  
Yi-Yuan Yu
Keyword(s):  
Plane Strain ◽  
Sandwich Plate ◽  
Classical Method ◽  
Separation Of Variables ◽  
Flexural Vibration ◽  
Time Dependent ◽  
Sandwich Plates ◽  
Simply Supported ◽  
Transverse Deflection ◽  
Plane Strain Case

On the basis of the new flexural theory of elastic sandwich plates recently developed [1–3], the problem of general forced flexural vibration of sandwich plates in the plane-strain case is solved. The classical method of separation of variables combined with the Mindlin-Goodman procedure [4] for treating time-dependent boundary conditions is used. As an example, the results are made use of in solving the problem of a simply supported sandwich plate in plane strain with one of the two end sections prescribed a transverse deflection varying with time.

BENDING BEHAVIOR OF SIMPLY SUPPOTED METALLIC SANDWICH PLATES WITH DIMPLED CORES

2008 ◽  
Vol 22 (31n32) ◽  
pp. 6179-6184 ◽  
Author(s):  
DAE-YONG SEONG ◽  
CHANG GYUN JUNG ◽  
DONG-YOL YANG ◽  
DONG GYU AHN
Keyword(s):  
High Precision ◽  
Sandwich Plate ◽  
Sheet Thickness ◽  
Radius Of Curvature ◽  
Sandwich Plates ◽  
Collapse Load ◽  
Forming Process ◽  
Simply Supported ◽  
Bending Behavior ◽  
Sandwich Core

Metallic sandwich plates are lightweight structural materials with load-bearing and multi-functional characteristics. Previous analytic studies have shown that the bendability of these plates increases as the thickness decreases. Due to difficulty in the manufacture of thin sandwich plates, dimpled cores (structures called egg-box cores) are employed as a sandwich core. High-precision dimpled cores are easily fabricated in a sectional forming process. The cores are then bonded with skin sheets by multi-point resistance welding. The bending characteristics of simply supported plates were observed by the defining measure, including the radius ratio of the small dimple, the thickness of a sandwich plate, and the pattern angle (0°/90°, 45°). Experimental results revealed that sandwich plates with a thickness of 2.2 mm and a pattern angle of 0°/90° showed good bendability as the punch stroke under a collapse load was longer than other cases. In addition, the gap between attachment points was found to be an important parameter for the improvement of the bendability. Finally, sandwich plates with dimpled cores were bent with a radius of curvature of 330 mm for the sheet thickness of 2.2 mm using an incremental bending apparatus.

Vibration and Damping Analysis of Rectangular Plate With Partially Covered Constrained Viscoelastic Layer

1987 ◽  
Vol 109 (3) ◽  
pp. 241-247 ◽  
Author(s):  
A. K. Lall ◽  
N. T. Asnani ◽  
B. C. Nakra
Keyword(s):  
Loss Factor ◽  
Ritz Method ◽  
Viscoelastic Damping ◽  
Viscoelastic Layer ◽  
Transverse Displacement ◽  
Modal System ◽  
Resonant Frequencies ◽  
Simply Supported ◽  
The Core ◽  
Single Term

The Rayleigh-Ritz method is applied for the damping analysis offlexural vibrations of a simply supported plate, partially covered with constrained viscoelastic damping treatment. The anaysis is carried out in terms of resonant frequencies and associated modal system loss factors. Single-term solutions for respective modes are assumed for the longitudinal displacements of the constraining layer and the transverse displacement of the plate. The variations of the resonant frequency and the associated modal loss factor with the coverage percentage, the coverage location, the core shear modulus and the thickness of the constrained and the constraining layers have been reported.

An Analysis of Viscoelastic Damping Characteristics of a Simply-Supported Sandwich Beam

1971 ◽  
Vol 93 (4) ◽  
pp. 1239-1244 ◽  
Author(s):  
A. Chatterjee ◽  
J. R. Baumgarten
Keyword(s):  
Energy Method ◽  
Sandwich Beam ◽  
Core Material ◽  
Viscoelastic Damping ◽  
Experimental Measurements ◽  
Simply Supported ◽  
The Core ◽  
Damping Characteristics ◽  
Viscoelastic Core ◽  
Theoretical Predictions

An energy method is employed to analyze the damping in the fundamental mode of a simply-supported sandwich beam with viscoelastic core material sandwiched between two elastic metallic layers called the facings. The theory developed herein enables one to predict the damped natural frequency and the damping (in terms of logarithmic decrement) of the transverse vibration of a beam of known dimensions, provided the moduli-frequency characteristics of the core material are known. Experimental measurements bear out the accuracy of the theoretical predictions. The theory can very easily be extended for the analysis of higher discrete modes.

Bending Properties of Laser Welded Web-Core Steel Sandwich Plates

2014 ◽  
Vol 936 ◽  
pp. 1451-1455 ◽  
Author(s):  
Xiao Xia Jiang ◽  
Liang Zhu ◽  
Ji Sen Qiao ◽  
Yi Xiong Wu ◽  
Zhu Guo Li ◽  
...  
Keyword(s):  
Finite Element ◽  
Sandwich Plate ◽  
Finite Element Simulations ◽  
Bending Test ◽  
Sandwich Plates ◽  
Bending Properties ◽  
Three Point Bending ◽  
Weld Width ◽  
The Core ◽  
Good Agreement

This paper presents a detailed discussion of the bending properties of laser welded web-core steel sandwich plates and the influence of weld width on stiffness and strength. The over-hanging three point bending test was conducted on the laser welded web-core steel sandwich plates with various welds width by self-designed device, together with the finite element simulations. A good agreement is obtained between the 2D FE analyses and experiment results. The stiffness and strength of the sandwich plates increased with the increasing of weld width, especially for the weld width lower than 60% thickness of the core plate. It is necessary to consider the weld width in the design and evaluation of the stiffness and strength of the laser welded web-core sandwich plate. Base on the results, the FEM is the priority to analysis bending properties of laser welded web-core steel sandwich plates.

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.

Study on Bending, Buckling and Free Vibration of Hard-Core Sandwich Plate Based on Revising the Soft-Core Reissner Theory

2014 ◽  
Vol 945-949 ◽  
pp. 790-794 ◽  
Author(s):  
Hai Yan Zeng ◽  
Ren Jun Yan ◽  
Yao Yu Hu
Keyword(s):  
Free Vibration ◽  
Sandwich Plate ◽  
Hard Core ◽  
High Strength ◽  
Soft Core ◽  
Sandwich Plates ◽  
The Core ◽  
Reissner Theory ◽  
Core Theory ◽  
Low Weight

The use of sandwich structures in various engineering fields is growing rapidly because of advantageous features such as low weight and high strength-to-weight ratio.The existing theories are all based on soft core assumption. In this case, the in-plane stress and the stiffness of the core are not included. It has been shown that Ressiner theory is inadequate for the analysis of hard-core sandwich plates. Different revision factors were put forward in this paper to revise the bending, buckling and free vibration results of soft-core Reissner theory for hard-core sandwich plates. The results show that the revised results go well with the hard core theory, so that its validity is confirmed.

Cylindrical Buckling of Sandwich Plates

1946 ◽  
Vol 13 (4) ◽  
pp. A253-A260
Author(s):  
J. N. Goodier
Keyword(s):  
Plane Strain ◽  
Sandwich Plate ◽  
Core Material ◽  
Sandwich Plates ◽  
The Core

Abstract In the buckling of “sandwich plates” with a relatively easily deformed interior, or core, material, the core is not stiff enough to keep plane sections plane when the bending occurs. The core must then be analyzed according to the equations of plane strain, but the fact that the bending takes place in the presence of thrust means that terms representing the destabilizing tendency of the thrust must be included. The resulting problem is solved in the present paper for a sandwich plate in “cylindrical buckling”—that is in a mode analogous to that of the hinged column.

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.

Elastic Foundation Analysis of Uniformly Loaded Functionally Graded Viscoelastic Sandwich Plates

2012 ◽  
Vol 28 (3) ◽  
pp. 439-452 ◽  
Author(s):  
A. M. Zenkour ◽  
M. Sobhy
Keyword(s):  
Power Law ◽  
Sandwich Plate ◽  
Plate Theory ◽  
Functionally Graded ◽  
Sandwich Plates ◽  
Equilibrium Equations ◽  
Graded Material ◽  
Plate Aspect Ratio ◽  
Type V ◽  
Power Law Index

AbstractThis paper deals with the static response of simply supported functionally graded material (FGM) viscoelastic sandwich plates subjected to transverse uniform loads. The FG sandwich plates are considered to be resting on Pasternak's elastic foundations. The sandwich plate is assumed to consist of a fully elastic core sandwiched by elastic-viscoelastic FGM layers. Material properties are graded according to a power-law variation from the interfaces to the faces of the plate. The equilibrium equations of the FG sandwich plate are given based on a trigonometric shear deformation plate theory. Using Illyushin's method, the governing equations of the viscoelastic sandwich plate can be solved. Parametric study on the bending analysis of FG sandwich plates is being investigated. These parameters include (i) power-law index, (ii) plate aspect ratio, (iii) side-to-thickness ratio, (iv) loading type, (v) foundation stiffnesses, and (vi) time parameter.

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