General instability and face wrinkling of sandwich plates - Unified theory and applications

Benson, A.; Mayers, J.

doi:10.2514/6.1966-138

Cited by 7 publications

(6 citation statements)

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“…Different approaches have been used for representing the core's behavior, all of which retain the transverse normal deformation in order to capture the wrinkling modes. A common assumption makes use of anti-plane cores, which disregards the in-plane load carrying capability of the core [21,[41][42][43]. This hypothesis has been shown to give misleading results not only when the core is isotropic [44], but also when the core is highly orthotropic, e.g., for honeycomb cores [30].…”

Section: Models For Overall Buckling and Wrinkling Of Sandwich Strutsmentioning

confidence: 99%

Linearized global and local buckling analysis of sandwich struts with a refined quasi-3D model

D′Ottavio¹,

Polit²

2014

Acta Mech

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HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

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Section: Models For Overall Buckling and Wrinkling Of Sandwich Strutsmentioning

confidence: 99%

Linearized global and local buckling analysis of sandwich struts with a refined quasi-3D model

D′Ottavio¹,

Polit²

2014

Acta Mech

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“…Therefore, the natural frequencies of the sandwich beam, which are approximated using the procedure outlined above, do not differ significantly from those obtained from the consistent formulation where the two Timoshenko beam equations are used, and the main unknowns are the transverse displacement, w, and bending slope, . The term ''consistent'' as used here implies that the total order of the governing differential equations matches the number of boundary conditions imposed on the beam [19].…”

Section: Classical Sandwich Analysismentioning

confidence: 99%

Analytical and Experimental Study of Free Vibration Response of Soft-core Sandwich Beams

Sokolinsky

Bremen

Lavoie

et al. 2004

Jnl of Sandwich Structures & Materials

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The natural frequencies and corresponding vibration modes of a cantilever sandwich beam with a soft polymer foam core are predicted using the higher-order theory for sandwich panels (HSAPT), a two-dimensional finite element analysis, and classical sandwich theory. The predictions of the higher-order theory are shown to be in good agreement with experimental measurements made with a simple experimental setup, as well as with finite element analysis. Experimental observations and analytical predictions show that the classical sandwich theory is not capable of accurately predicting the free vibration response of soft-core sandwich beams. It is shown that the vibration response of the cantilever soft-core sandwich beam consists of a group of five lower frequency shear (antisymmetric) modes that are followed by a group of four thickness-stretch (symmetric) modes. For the higher frequency range, the vibration modes alternate between groups of one-two antisymmetric and symmetric modes. For very high frequencies, interactive vibration response is observed. Experiments show that the damping properties of the foam core are manifest most noticeably in the case of thickness-stretch vibration modes, whereas the influence of damping on the anti-symmetric modes is insignificant.

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“…If the global buckling of a sandwich material can be easily viewed as the classical buckling of a homogeneous structure (as soon as the equivalent properties have been properly derived), the local buckling analysis requires the use of advanced models. If the earliest contributions rely on uncoupled formulations, where the global and local buckling analyses are treated separately, many authors have tried to achieve unified models capable of describing both global and local modes (both symmetric/hourglass and antisymmetric/snaking) in the particular case of a sandwich column under axial compression (Benson and Mayers [3] have been the first to suggest a unified approach to solve the overall buckling and wrinkling problems simultaneously). Among them, a hybrid beam/2D model (with no kinematic assumption in the core layer) was recently developed by Douville and Le Grognec [4] which was first able to derive closed-form expressions of both buckling and wrinkling critical values of sandwich beamcolumns (accounting for all mode types) with a very good accuracy, compared to the numerous simplified models in earlier literature (see also [4] for a comprehensive review of analytical or numerical models for the buckling analysis of sandwich beam-columns/plates under various loading conditions, using different simplified kinematic assumptions).…”

Section: Introductionmentioning

confidence: 99%

Buckling analysis of a reinforced sandwich column using the Bloch wave theory

Dong¹,

Grognec²

2017

Thin-Walled Structures

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International audienceThis paper deals with sandwich structures whose core layer is made of a homogeneous foam periodically strengthened by orthogonal reinforcements. Beside traditional sandwiches which generally display satisfactory specific flexural properties but fatally insubstantial stiffnesses in the through-thickness direction, 3D reinforced sandwich materials provide optimal out-of-plane mechanical properties. Despite this, buckling remains one of the major failure modes of such structures and, compared to the case of traditional sandwiches, both global and local buckling phenomena are more complicated in presence of transverse reinforcements. Indeed, in most cases, the modal deformed shapes involve simultaneously the skins and the reinforcements in an intricate way. The main feature of these buckling modes is periodicity, but the typical wave length appears to be generally different from the characteristic length between reinforcements. However, it is possible to investigate such periodic modes on a simple unit cell by using the so-called Bloch wave theory. In this work, an efficient procedure is defined so as to deal with the buckling behavior of a sandwich column with periodic orthogonal reinforcements. First, a numerical method is implemented in the framework of the commercial software Abaqus. The evaluation of the critical strains is performed on a unit cell: an initial average compressive strain is enforced, then natural frequencies are computed and the critical strains are deduced by extrapolation of the previous eigenvalues. A Python program is developed so as to automate these successive calculation steps and a Fortran program is also needed (within Abaqus) in order to cope with the two real and imaginary problems to be solved due to the Bloch periodic conditions. Furthermore, an exact analytical solution of this problem is obtained in the particular case of a reinforced sandwich with no foam core (for simplicity purposes). The analytical and numerical solutions obtained with a unit cell model are finally compared to the results of numerical computations performed on a complete beam with an arbitrary number of cells, for validation purposes. The critical strains/displacements are found to be in very good agreement and the buckling modes rebuilt from the real and imaginary components of the unit cell modal solutions perfectly coincide with the buckling modes of the complete beam obtained through a linearized buckling analysis

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General instability and face wrinkling of sandwich plates - Unified theory and applications

Cited by 7 publications

References 0 publications

Linearized global and local buckling analysis of sandwich struts with a refined quasi-3D model

Linearized global and local buckling analysis of sandwich struts with a refined quasi-3D model

Analytical and Experimental Study of Free Vibration Response of Soft-core Sandwich Beams

Buckling analysis of a reinforced sandwich column using the Bloch wave theory

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