Bending analysis of a general cross-ply laminate using 3D elasticity solution and layerwise theory

H Yazdani Sarvestani,A Naghashpour,M Heidari-Rarani

doi:10.1007/s40091-014-0073-2

H Yazdani Sarvestani, A Naghashpour + Show 1 more

https://doi.org/10.1007/s40091-014-0073-2

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Abstract

In this study, the analytical solution of inter- laminar stresses near the free edges of a general (symmetric and unsymmetric layups) cross-ply composite laminate subjected to pure bending loading is presented based on Reddy's layerwise theory (LWT) for the first time. First, the reduced form of displacement field is obtained for a general cross-ply composite laminate subjected to a bend- ing moment by elasticity theory. Then, first-order shear deformation theory of plates and LWT is utilized to determine the global and local deformation parameters appearing in the displacement fields, respectively. One of the main advantages of the developed solution based on the LWT is exact prediction of interlaminar stresses at the boundary layer regions. To show the accuracy of this solution, three-dimensional elasticity bending problem of a laminated composite is solved for special set of boundary conditions as well. Finally, LWT results are presented for edge-effect problems of several symmetric and unsym- metric cross-ply laminates under the bending moment. The obtained results indicate high stress gradients of interlam- inar stresses near the edges of laminates.

Highlights

With the ever-increasing application of laminated composite, especially in aerospace industries which require strong, stiff, and lightweight structural components; interlaminar stresses play a significant role in the analysis and design of composite structures since they can lead to catastrophic failure modes like delamination
In this study, the analytical solution of interlaminar stresses near the free edges of a general cross-ply composite laminate subjected to pure bending loading is presented based on Reddy’s layerwise theory (LWT) for the first time
The reduced form of displacement field is obtained for a general cross-ply composite laminate subjected to a bending moment by elasticity theory

Summary

Introduction

With the ever-increasing application of laminated composite, especially in aerospace industries which require strong, stiff, and lightweight structural components; interlaminar stresses play a significant role in the analysis and design of composite structures since they can lead to catastrophic failure modes like delamination. It appears that the failure of structural components because of bending loads much more often than the in-plane loads; little work effort has been dedicated so far for development of the theoretical or numerical models for predicting boundary layer effects of bending of structural laminates For this reason, the present study deals with the analytical solution of interlaminar stresses near free edges of a general cross-ply composite laminate subjected to a bending moment. The reduced form of displacement field is obtained for a general cross-ply composite laminate subjected to a bending moment by elasticity theory. To determine global and local deformation parameters appearing in the reduced displacement fields of elasticity formulation, the first-order shear deformation theory of plates (FSDT) and LWT is utilized, respectively. The parameters B2 and B6, which are needed in (4), are determined to be as follows: B6 B2

B11 A11D11 À

Results and discussion

Conclusions