A Comparison of the Structural Response of Clamped and Simply Supported Sandwich Beams With Aluminium Faces and a Metal Foam Core

Plastic collapse modes for clamped sandwich beams have been investigated experimentally and theoretically for the case of aluminium face sheets and a metal foam core. Three initial collapse mechanisms have been identified and explored with the aid of a collapse mechanism map. It is shown that the effect of clamped boundary conditions is to drive the deformation mechanism towards plastic stretching of the face sheets. Consequently, the ultimate strength and level of energy absorption of the sandwich beam are set by the face sheet ductility. Limit load analyses have been performed and simple analytical models have been developed in order to predict the postyield response of the sandwich beams; these predictions are validated by both experiments and finite elements simulations. It is shown experimentally that the ductility of aluminium face sheets is enhanced when the faces are bonded to a metal foam core. Finally, minimum weight configurations for clamped aluminium sandwich beams are obtained using the analytical formulas for sandwich strength, and the optimal designs are compared with those for sandwich beams with composite faces and a polymer foam core.

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Collapse mechanisms of sandwich beams with composite faces and a foam core, loaded in three-point bending. Part I: analytical models and minimum weight design

International Journal of Mechanical Sciences ◽

10.1016/j.ijmecsci.2004.04.003 ◽

2004 ◽

Vol 46 (4) ◽

pp. 561-583 ◽

Cited By ~ 149

Author(s):

Craig A. Steeves ◽

Norman A. Fleck

Keyword(s):

Minimum Weight ◽

Analytical Models ◽

Foam Core ◽

Sandwich Beams ◽

Minimum Weight Design ◽

Three Point Bending ◽

Collapse Mechanisms ◽

Weight Design

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Plastic Analysis of Metal Foam Core Sandwich Beam Transversely Loaded by a Flat Punch: Combined Local Denting and Overall Deformation

Journal of Applied Mechanics ◽

10.1115/1.4005561 ◽

2012 ◽

Vol 79 (4) ◽

Cited By ~ 21

Author(s):

Qing Hua Qin ◽

T. J. Wang

Keyword(s):

Metal Foam ◽

Sandwich Beam ◽

Plastic Behavior ◽

Foam Core ◽

Sandwich Beams ◽

Low Velocity ◽

Flat Punch ◽

Rigid Plastic ◽

Energy Impact ◽

Impact Problems

The objective of this work is to investigate the quasi-static plastic behavior of a fully clamped metal foam core sandwich beam transversely loaded by a flat punch. A rigid-plastic beam-on-foundation model is extended to study the local denting deformation of a metal foam core sandwich beam. The effects of local denting and core strength on the overall deformation are incorporated in the analysis. Analytical solutions are derived for three different regimes of post-yield deformation mechanisms. Additionally, finite element results are obtained. Comparisons of the present analytical predictions with numerical, previous experimental, and analytical results are presented, respectively. It is shown that local denting has a significant effect on the finite deflection response of the metal foam core sandwich structure. The load-carrying and energy absorption capacities of sandwich beams may be overestimated if the effect of local denting is neglected in analysis. It is demonstrated that the present analytial model can reasonably predict the behaviors of post-yield deformation of sandwich beams. Moreover, the present analytical method can be extended to predict the low velocity/energy impact problems of sandwich structures.

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The Failure Behavior of Geometrically Asymmetric Metal Foam Core Sandwich Beams Under Three-Point Bending

Journal of Applied Mechanics ◽

10.1115/1.4027200 ◽

2014 ◽

Vol 81 (7) ◽

Cited By ~ 17

Author(s):

Jianxun Zhang ◽

Qinghua Qin ◽

Weilong Ai ◽

Huimin Li ◽

T. J. Wang

Keyword(s):

Failure Mechanism ◽

Failure Modes ◽

Metal Foam ◽

Minimum Weight ◽

Failure Behavior ◽

Foam Core ◽

Sandwich Beams ◽

Three Point Bending ◽

Initial Failure ◽

Core Height

The failure behavior of geometrically asymmetric sandwich beams with a metal foam core is analytically and experimentally investigated. New initial failure modes of the asymmetric sandwich beams are observed under three-point bending, i.e., face yield, face wrinkling, core shear A, core shear AB, core shear A-AB, and indentation. It is shown that the initial failure modes of sandwich beams depend on the span of the beam, the thicknesses of top and bottom face sheets, core height and material properties. We derived the analytical formulae for the initial failure loads and then constructed the initial failure mechanism maps for the geometrically asymmetric sandwich beams. It is shown that the analytically predicted initial failure mechanism maps are in good agreement with the experimental results, which are clearly different from the symmetric sandwich beams. As a preliminary application, the minimum weight designs are presented for asymmetric metal sandwich beams.

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

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.525-526.357 ◽

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.

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Effective design of a sandwich beam with a metal foam core

Thin-Walled Structures ◽

10.1016/j.tws.2007.03.005 ◽

2007 ◽

Vol 45 (4) ◽

pp. 432-438 ◽

Cited By ~ 35

Author(s):

E. Magnucka-Blandzi ◽

K. Magnucki

Keyword(s):

Metal Foam ◽

Sandwich Beam ◽

Foam Core ◽

Effective Design

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Creep Responses of Smart Sandwich Composites at Multiple Length Scales: Experiments and Modeling

Journal of Engineering Materials and Technology ◽

10.1115/1.4002643 ◽

2010 ◽

Vol 133 (1) ◽

Cited By ~ 4

Author(s):

Anaïs Farrugia ◽

Charles Winkelmann ◽

Valeria La Saponara ◽

Jeong Sik Kim ◽

Anastasia H. Muliana

Keyword(s):

Creep Behavior ◽

Composite Structures ◽

Effective Properties ◽

Micromechanical Model ◽

Foam Core ◽

Sandwich Beams ◽

Fiber Reinforced ◽

Polymer Foam ◽

Creep Tests ◽

Unique Challenge

In service, composite structures present the unique challenge of damage detection and repair. Piezoelectric ceramic, such as lead zirconate titanate (PZT), is often used for detecting damage in composites. This paper investigates the effect of embedded PZT crystals on the overall creep behavior of sandwich beams comprising of glass fiber reinforced polymer laminated skins and polymer foam core, which could potentially be used as a damage-detecting smart structure. Uniaxial quasi-static and creep tests were performed on the glass/epoxy laminated composites having several fiber orientations, 0 deg, 45 deg, and 90 deg, to calibrate the elastic and viscoelastic properties of the fibers and matrix. Three-point bending creep tests at elevated temperature (80°C) were then carried out for a number of control sandwich beams (no PZT crystal) and conditioned sandwich beams (with PZT crystals embedded in the center of one facesheet). Lateral deflection of the sandwich beams was monitored for more than 60 h. The model presented in this paper is composed by two parts: (a) a simplified micromechanical model of unidirectional fiber reinforced composites used to obtain effective properties and overall creep response of the laminated skins and (b) a finite element method to simulate the overall creep behavior of the sandwich beams with embedded PZT crystals. The simplified micromechanical model is implemented in the material integration points within the laminated skin elements. Fibers are modeled as linear elastic, while a linearized viscoelastic material model is used for the epoxy matrix and foam core. Numerical results on the creep deflection of the smart sandwich beams show good correlations with the experimental creep deflection at 80°C, thus proving that this model, although currently based on material properties reported at room temperature, is promising to obtain a reasonable prediction for the creep of a smart sandwich structure at high temperatures.

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Design and Characterization of Small-Scale Sandwich Beams Fabricated by Photolithography and Electrodeposition

10.1115/imece2000-1103 ◽

2000 ◽

Author(s):

Yuki Sugimura

Keyword(s):

Aspect Ratio ◽

High Aspect Ratio ◽

Sandwich Beam ◽

Beam Theory ◽

Shear Stiffness ◽

Open Architecture ◽

Small Scale ◽

Sandwich Beams ◽

The Face ◽

Micrometer Size

Abstract Small-scale sandwich beams with core structures having cell diameters and wall widths on the order of 500 μm and 100 μm, respectively, have been produced through fabrication methods that combine photolithography and electrodeposition. Two core configurations have been examined: 1) regular hexagonal honeycomb and 2) high-aspect ratio hexagonal shells having an open architecture. The bending response of the sandwich beams has been examined and compared with the beam theory predictions. Shear stiffness of the honeycomb core was considerably high and therefore the bending behavior was dominated by the face sheets. The bending of the sandwich specimens with the hexagonal shells, on the other hand, was largely dependent on the core. The sandwich beam dimensions investigated in this study have not been optimized for weight minimization and structural efficiency. Further advances in fabrication methods to produce micrometer-size features and high-aspect ratio cores will enable realization of structurally efficient, lightweight sandwich beams and panels that can be used as multifunctional components in small-scale devices.

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