Flexural Vibration of Segmented Elastic-Viscoelastic Sandwich Beams

1975 ◽  
Vol 42 (4) ◽  
pp. 897-900
Author(s):  
B. E. Sandman
Keyword(s):  
Steady State ◽  
Numerical Study ◽  
Sandwich Beam ◽  
Flexural Vibration ◽  
Middle Layer ◽  
Resonant Mode ◽  
Sandwich Beams ◽  
Simply Supported ◽  
Viscoelastic Core ◽  
Longitudinal Nonuniformity

A pair of governing differential equations form the basis for the study of steady-state forced vibration of a sandwich beam with longitudinal nonuniformity in the stiffness and mass of the middle layer. The spatial solution for simply supported boundary conditions is obtained by a Fourier analysis of both material and kinematic variations. The solution is utilized in the numerical study of a sandwich beam with a segmented configuration of elastic and viscoelastic core materials. The results exemplify a tuned configuration of core segments for optimum damping of the first resonant mode.

Analysis of Interface Deformation of Steel-Concrete-Steel Sandwich Beam

2012 ◽  
Vol 525-526 ◽  
pp. 357-360
Author(s):  
Pei Xiu Xia ◽  
Guang Ping Zou ◽  
Zhong Liang Chang
Keyword(s):  
Sandwich Beam ◽  
Analytical Models ◽  
Sandwich Beams ◽  
Interface Deformation ◽  
Simply Supported ◽  
Interface Slip ◽  
Steel Panels ◽  
Uniformly Distributed Loads ◽  
Relationship Of ◽  
The Relationship

The effect of the interface slip is neglected in most studies on calculating deflection of sandwich beams. By taking a simply supported sandwich beams under uniformly distributed loads as an example, simplified analytical models of the interface slip are established, and corresponding clculation formulas of interface slip between steel panels and concrete and section curvatures are derived. The formula for deflection of sandwich beams are then presented. This formula reflects the relationship of influence each other between the interface slip and deflection.

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.

Static Response of Stiff-Cored Unsymmetric Sandwich Beams

1976 ◽  
Vol 98 (2) ◽  
pp. 391-396 ◽  
Author(s):  
D. K. Rao
Keyword(s):  
Variational Method ◽  
Flexural Rigidity ◽  
Sandwich Beam ◽  
Sandwich Beams ◽  
Static Response ◽  
Simply Supported ◽  
The Core ◽  
Distributed Load ◽  
Very High ◽  
Maximum Stresses

Improved equations governing the deflection of an unsymmetric sandwich beam (which include the effect of extensional and bending rigidities of its stiff core) are derived using a variational method. The effect of face-thickness ratio on the contribution of the core to the overall flexural rigidity is studied. Numerical results for simply supported and fixed-fixed beams subjected to a uniformly distributed load are obtained by using Laplace transforms. These results show that ignoring the bending and extensional effects of a stiff core can cause errors in maximum deflections as high as 20 percent. The corresponding errors in stresses are very high, and they vary from 10 to 150 percent. Hence, it is suggested that the extensional and bending effects of the core should be taken into account when one is interested in calculating the maximum stresses in stiff-cored beams.

Damping in Sandwich Beams With Shear-Flexible Cores

1967 ◽  
Vol 89 (4) ◽  
pp. 662-670 ◽  
Author(s):  
C. W. Bert ◽  
D. J. Wilkins ◽  
W. C. Crisman
Keyword(s):  
Free Vibration ◽  
Natural Frequency ◽  
Material Properties ◽  
Sandwich Beam ◽  
Flexural Vibration ◽  
Logarithmic Decrement ◽  
Sandwich Beams ◽  
Hexagonal Cell ◽  
Modal Shape ◽  
Beam Geometry

This paper is a theoretical and experimental study of the effect of core shear flexibility on the lowest natural frequency, node locations, and damping in sandwich beams with cores of high shear flexibility as exemplified by honeycomb-type cores. A new method of analysis is presented for predicting the logarithmic decrement for damping in sandwich beams undergoing free vibration, provided that the beam geometry and constitutent material properties are known. Natural frequency, modal shape, and logarithmic decrement are all dependent upon the dynamic shear coefficient. Two new simplified derivations for this coefficient are presented in this paper. Flexural vibration experiments were conducted on free-free sandwich beam strips at frequencies from 300 to 700 cps. Facings were glass-epoxy laminates and cores were hexagonal-cell honeycomb of either aluminum or glass-phenolic. For each beam, lowest natural frequency, associated node locations, and logarithmic decrement in free vibration were measured and compared with those predicted by applying four different theories.

Nonlinear Vibration of Sandwich Beams with Functionally Graded Negative Poisson’s Ratio Honeycomb Core

2019 ◽  
Vol 19 (03) ◽  
pp. 1950034 ◽  
Author(s):  
Chong Li ◽  
Hui-Shen Shen ◽  
Hai Wang
Keyword(s):  
Nonlinear Vibration ◽  
Poisson’S Ratio ◽  
Sandwich Beam ◽  
Flexural Vibration ◽  
Functionally Graded ◽  
Poisson's Ratio ◽  
Sandwich Beams ◽  
Negative Poisson’S Ratio ◽  
Honeycomb Core ◽  
Negative Poisson's Ratio

This paper investigates the nonlinear flexural vibration of sandwich beams with functionally graded (FG) negative Poisson’s ratio (NPR) honeycomb core in thermal environments. The novel constructions of sandwich beams with three FG configurations of re-entrant honeycomb cores through the beam thickness direction are proposed. The temperature-dependent material properties of both face sheets and core of the sandwich beams are considered. 3D full-scale finite element analyses are conducted to investigate the nonlinear vibration, and the variation of effective Poisson’s ratio (EPR) of the sandwich beams in the large deflection region. Numerical simulations are carried out for the sandwich beam with FG-NPR honeycomb core in different thermal environmental conditions, from which results for the same sandwich beam with uniform distributed NPR honeycomb core are obtained as a basis for comparison. The effects of FG configurations, temperature changes, boundary conditions, and facesheet-to-core thickness ratios on the nonlinear vibration ratio curves and EPR–deflection curves of sandwich beams are discussed in detail.

An Investigation of the Effect of interrupted fin arrangements on the Thermal Performance of a Heat Sink under a Free Convection Condition

2019 ◽  
Vol 7 (1) ◽  
pp. 43-53
Author(s):  
Abbas Jassem Jubear ◽  
Ali Hameed Abd
Keyword(s):  
Heat Transfer ◽  
Steady State ◽  
Natural Convection ◽  
Thermal Performance ◽  
Heat Sink ◽  
Numerical Study ◽  
Ansys Fluent ◽  
Fluent Software ◽  
Steady State Heat ◽  
Steady State Heat Transfer

The heat sink with vertically rectangular interrupted fins was investigated numerically in a natural convection field, with steady-state heat transfer. A numerical study has been conducted using ANSYS Fluent software (R16.1) in order to develop a 3-D numerical model.  The dimensions of the fins are (305 mm length, 100 mm width, 17 mm height, and 9.5 mm space between fins. The number of fins used on the surface is eight. In this study, the heat input was used as follows: 20, 40, 60, 80, 100, and 120 watts. This study focused on interrupted rectangular fins with a different arrangement and angle of the fins. Results show that the addition of interruption in fins in various arrangements will improve the thermal performance of the heat sink, and through the results, a better interruption rate as an equation can be obtained.

Effect of Viscous Dissipation on MHD Williamson Nanofluid Flow in a Porous Medium

2019 ◽  
Vol 8 (3) ◽  
pp. 5795-5802 ◽  
Keyword(s):  
Porous Medium ◽  
Steady State ◽  
Numerical Solution ◽  
Viscous Dissipation ◽  
Flow Problem ◽  
Numerical Study ◽  
Steady State Flow ◽  
Nanofluid Flow ◽  
Shooting Technique ◽  
Order Four

The main objective of this paper is to focus on a numerical study of viscous dissipation effect on the steady state flow of MHD Williamson nanofluid. A mathematical modeled which resembles the physical flow problem has been developed. By using an appropriate transformation, we converted the system of dimensional PDEs (nonlinear) into coupled dimensionless ODEs. The numerical solution of these modeled ordinary differential equations (ODEs) is achieved by utilizing shooting technique together with Adams-Bashforth Moulton method of order four. Finally, the results of discussed for different parameters through graphs and tables.

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