On Wrinkling in Sandwich Panels with an Orthotropic Core

Abstract

This paper deals with the local loss of stability (wrinkling) problem of a thin facing of a sandwich panel. Classical solutions to the problem of a facing instability resting on a homogeneous and isotropic substructure (a core) are compared. The relations between strain energy components associated with different forms of core deformations are discussed. Next, a new solution for the orthotropic core is presented in detail, which is consistent with the classic solution for the isotropic core. Selected numerical examples confirm the correctness of the analytical formulas. In the last part, parametric analyses are carried out to illustrate the sensitivity of wrinkling stress to a change in the material parameters of the core. These analyses illustrate the possibility of using the equations derived in the article for the variability of Poisson’s ratio from −1 to 1 and for material parameters strongly deviating from isotropy.

Influence of the Heterogeneity of the Core Material on the Local Instability of a Sandwich Panel

“…In other words, any vertical lines indicated before deformation remain vertical during wrinkling. The justification for this approach can be found, inter alia, in [ 24 ].…”

“…This work can be considered in the context of previous analyses [ 23 , 24 ]. These articles did not deal a heterogeneous core but a homogeneous orthotropic core.…”

“…It has been shown that this stress depends on both the modulus of elasticity and the shear modulus of the core material. In [ 24 ], an analytical solution for a compressed facing resting on an orthotropic core was presented. Classical solutions to the problem with a homogeneous isotropic core were also compared, showing differences in relation to the strain energy of the core.…”

Parameters Influence on the Dynamic Properties of Polymer-Matrix Composites Reinforced by Fibres, Particles, and Hybrids

“…In the current publications, researchers focus mainly on the strength and stiffness of composite materials, the method of the analytical prediction of these quantities, and multilevel simulations and experiments for individual types of composites. In the numerical and experimental studies, researchers not only analyse the static properties, but also the impact or combined ones [ 4 , 5 , 6 , 7 , 8 , 9 ]. However, in industrial applications, the composites are not only subjected to static loads, but also to the dynamic components of the loads, which are substantial, along with vibrations as natural parts of the mechanical-system operation.…”

Mechanics of Corrugated and Composite Materials

“…On the other hand, article [ 5 ] presented the important issue of thin facing wrinkling in sandwich panels with a soft core. The local loss of stability in thin facings obviously reduces the load-bearing capacity of the composite panels.…”