Bending analysis of a laminated composite patch considering the free-edge effect using a stress-based equivalent single-layer composite model

2011 ◽  
Vol 53 (8) ◽  
pp. 606-616 ◽  
Author(s):  
Jaehun Lee ◽  
Maenghyo Cho ◽  
Heung Soo Kim
Keyword(s):  
Edge Effect ◽  
Single Layer ◽  
Laminated Composite ◽  
Free Edge ◽  
Composite Model ◽  
Bending Analysis ◽  
Composite Patch ◽  
Layer Composite

Effect of heterogeneity at the fiber–matrix scale on predicted free-edge stresses for a [0°/90°]s laminated composite subjected to uniaxial tension

2018 ◽  
Vol 53 (5) ◽  
pp. 625-639 ◽  
Author(s):  
Michael Keith Ballard ◽  
John D Whitcomb
Keyword(s):  
Normal Stress ◽  
Uniaxial Tension ◽  
Edge Effect ◽  
Homogeneous Model ◽  
Laminated Composite ◽  
Free Edge ◽  
Orthotropic Materials ◽  
3D Analysis ◽  
Stress Distributions ◽  
Heterogeneous Model

The effect of the free-edge on the interlaminar stresses that develop in a thin-ply [0°/90°]s laminated composite under uniaxial tension was explored using finite element models that directly modeled the random heterogeneous microstructure and a model that treated the plies as homogeneous, orthotropic materials. The deformed cross-sections were compared for the two cases, showing that the homogeneous model generally captured the displacement field well but the heterogenous model exhibited local perturbations due to the microstructure. The interlaminar normal stress distributions along the ply interfaces were very different for two models. The heterogeneous model exhibited a complex pattern of stresses that were sensitive to nearby fibers. A comparison of the interlaminar shear stress distributions for the two models showed better agreement, though the heterogeneous model greatly differed from the homogeneous model when fibers or matrix pockets were close to the ply interface. After separating the effect of the fibers and the free-edge effect, the stresses that develop due to the free-edge effect matched well between the two models, except very close to the free-edge. It was shown that the Poisson’s ratios of the fibers and matrix significantly affect the stress distributions along the ply interface, and a matrix Poisson’s ratio could be selected that reduces the effect of the microstructure on the interlaminar normal stress. The study highlighted that a full 3D analysis can provide new insights for classical problems, and more optimal design of composites will require consideration of microstructural effects.

The Influence of Fiber/Matrix Debonding on Inelastic Micro-Mechanical Behavior of Cross-Ply IMC Composites

2010 ◽  
Author(s):  
Hessamodin Teimouri ◽  
Ali Abedian ◽  
Hengameh Farahpour
Keyword(s):  
Laminated Composite ◽  
Free Edge ◽  
Point Of View ◽  
Processing Temperature ◽  
Finite Element Models ◽  
Intermetallic Matrix ◽  
Layer Composite ◽  
Intermetallic Matrix Composite ◽  
Fiber Matrix Interface ◽  
Fiber Matrix

In this study the effect of stress field on delamination and fiber/matrix debonding in laminated composite panels is investigated from the micro-mechanical point of view by means of 3-D Finite Element Models. Specifically, the behavior of two-layer cross-ply symmetric laminates made up of SCS-6/Ti-24Al-11Nb Intermetallic Matrix Composite (IMC) during cooling from the processing temperature is studied. The results show that large plastic strains occur at the fiber/matrix interface at the fiber end on the laminate free edge which may eventually extend to the interface of the layers of the laminate inflicting delamination damage. This phenomenon is more serious at the corner areas of the laminate. It also can be shown that this situation is more serious for the four-layer laminate compared to the results of two-layer composite.

Continuous Strain Finite-Element Analysis of Free-Edge Effect in Laminated Composite Specimens

1988 ◽  
Vol 10 (2) ◽  
pp. 54 ◽  
Author(s):  
KL Reifsnider ◽  
GP Sendeckyj ◽  
SS Wang ◽  
WS Johnson ◽  
WW Stinchcomb ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Edge Effect ◽  
Laminated Composite ◽  
Free Edge ◽  
Element Analysis

Anisotropy of electromechanical parameters of a single-layer composite of the piezoceramic - polymer system

2021 ◽  
Vol 575 (1) ◽  
pp. 29-32
Author(s):  
D. I. Makarev ◽  
N. A. Shvetsova ◽  
A. N. Reznichenko ◽  
M. A. Lugovaya
Keyword(s):  
Polymer System ◽  
Single Layer ◽  
Layer Composite

scholarly journals Influence of pattern anisotropy on the structural behaviour of free-edge single-layer gridshells

2021 ◽  
Vol 8 (1) ◽  
pp. 119-129
Author(s):  
Fiammetta Venuti
Keyword(s):  
Single Layer ◽  
Free Edge ◽  
Boundary Structure ◽  
Structural Behaviour ◽  
Grid Pattern ◽  
Existing Building ◽  
Edge Orientation ◽  
Current Design ◽  
Service Conditions ◽  
Layer Steel

Abstract Free-edge gridshells represent the majority of built gridshells. Indeed, the gridshell reference geometry usually needs to be trimmed in order to provide building access or to insert the gridshell within an existing building, giving rise to one or more elastic boundaries. Despite the current design practice, so far a very limited number of scientific studies has been devoted to investigate the influence of elastic boundaries on the overall structural behaviour of gridshells. This paper focuses on the effects of the orientation of the boundary structure with respect to the grid direction. This is done by studying the buckling behaviour of an ideal single-layer steel gridshell, for different grid layout (quadrangular, hybrid, triangular) and orientation. The results of the parametric study demonstrate that the sensitivity of free-edge single-layer gridshells to the free-edge orientation strongly depends on the grid pattern. In particular, isotropic gridshells have shown an almost negligible influence of the free-edge orientation in terms of buckling load, in opposition to orthotropic gridshells. Moreover, the change in free-edge orientation induces significant variations of the global structural stiffness for all the layouts, resulting in possibly unacceptable displacements in service conditions.

Flutter of Perforated Metallic Plates Repaired with Cross-Ply Composite Patches

2009 ◽  
Vol 417-418 ◽  
pp. 709-712
Author(s):  
Ali Amin Yazdi ◽  
Jalil Rezaeepazhand
Keyword(s):  
Laminated Composite ◽  
Material Anisotropy ◽  
Perforated Plates ◽  
Closed Form Solutions ◽  
Finite Element Software ◽  
Composite Patch ◽  
Numerical Studies ◽  
Flutter Analysis ◽  
Flutter Boundary ◽  
Metallic Plates

This study investigates the application of laminated composite patches for enhancement of flutter behavior of perforated metallic plates repaired with an external composite patch. Due to material anisotropy and discontinuity in geometry involved in flutter analysis of repaired plates, closed form solutions are practically unobtainable. Numerical studies using commercial finite element software were conducted to investigate the effects of variation in lamination parameters on the flutter boundary of perforated plates repaired with cross-ply composite patches. Both ply-level and sub-laminate level configurations are investigated. Presented results illustrate that flutter boundaries of perforated plates can be changed by choosing proper stacking sequence for composite patches.

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