A solution including skin effect for stiffness and stress field of sandwich honeycomb core

Honeycomb sandwich panels have been increasingly used in every possible field, and their efficient load carrying capacity attributes have attracted considerable attention. All previous studies have been focused mainly on stiffness, neglecting for the most part skin effects. This paper represents an important further contribution by developing an analytical model that permits the computation of stiffnesses as well as interfacial stresses considering the skin-effect for hexagonal honeycomb sandwich, subjected to in-plane and out-of-plane forces. An explicit analytical model is derived based on equilibrium equations, where boundary conditions imposed by the skin effect are appropriately considered. The accuracy of the solution is verified through close correlations with existing stiffness formulations and finite element results. The skin effect on both stiffness and interfacial stress distribution is analytically defined. The present model is then used to carry out a parametric study on interfacial stresses, and to detect the critical sections in the structure where further consideration should be given for design purposes. The method provided in this study can be used for accurate analysis and design of sandwich structures.

[1]  Julio F. Davalos,et al.  Modeling and characterization of fiber-reinforced plastic honeycomb sandwich panels for highway bridge applications , 2001 .

[2]  W. Becker,et al.  The in-plane stiffnesses of a honeycomb core including the thickness effect , 1998 .

[3]  Michel Grédiac,et al.  A finite element study of the transverse shear in honeycomb cores , 1993 .

[4]  Wilfried Becker,et al.  A refined analysis of the effective elasticity tensor for general cellular sandwich cores , 2001 .

[5]  M. Ashby,et al.  Cellular solids: Structure & properties , 1988 .

[6]  Ahmed K. Noor,et al.  Computational Models for Sandwich Panels and Shells , 1996 .

[7]  J. Penzien,et al.  Effective shear modulus of honeycomb cellular structure , 1964 .

[8]  H. G. Allen.  Analysis and design of structural sandwich panels , 1969 .

[9]  Robert D. Adams,et al.  The dynamic shear properties of structural honeycomb materials , 1993 .

[10]  K. Evans,et al.  Models for the elastic deformation of honeycombs , 1996 .

[11]  Jandro L. Abot,et al.  Fabrication, testing and analysis of composite sandwich beams , 2000 .

[12]  M. Ashby,et al.  The effect of non-uniformity on the in-plane modulus of honeycombs , 1999 .

[13]  S. Kelsey,et al.  The Shear Modulus of Foil Honeycomb Cores , 1958 .

[14]  Guangyu Shi,et al.  Equivalent transverse shear stiffness of honeycomb cores , 1995 .

[15]  W. Becker,et al.  Singular stress fields in cellular cores for structural sandwich panels , 2001 .

[16]  W. Becker,et al.  Assessment of the delamination hazard of the core face sheet bond in structural sandwich panels , 2001 .

[17]  J. Vinson.  The Behavior of Sandwich Structures of Isotropic and Composite Materials , 1999 .

[18]  Ahmed K. Noor,et al.  Structural analysis of the adhesive bond in a honeycomb core sandwich panel , 1997 .

[19]  Julio F. Davalos,et al.  TRANSVERSE SHEAR STIFFNESS OF COMPOSITE HONEYCOMB CORE WITH GENERAL CONFIGURATION , 2001 .

[20]  Pizhong Qiao,et al.  Homogenized elastic properties of honeycomb sandwich with skin effect , 2002 .

[21]  W. E. Warren,et al.  Foam mechanics: the linear elastic response of two-dimensional spatially periodic cellular materials , 1987 .