Some characteristics of distributions of free-edge interlaminar stresses in composite laminates

1990 ◽  
Vol 26 (3) ◽  
pp. 331-351 ◽  
Author(s):  
Ye Lln
Keyword(s):  
Composite Laminates ◽  
Free Edge ◽  
Interlaminar Stresses

Simple Solutions of the Free-Edge Stresses in Composite Laminates under Thermal and Mechanical Loads

1994 ◽  
Vol 28 (6) ◽  
pp. 573-586 ◽  
Author(s):  
Wan-Lee Yin
Keyword(s):  
Composite Laminates ◽  
Constitutive Relations ◽  
Free Edge ◽  
Normal Derivative ◽  
Boundary Region ◽  
Material Behavior ◽  
Interlaminar Stresses ◽  
Inelastic Material ◽  
Stress Functions ◽  
Temperature Loads

Intense and localized interlaminar stresses generally occur in a narrow boundary region near the free edge of a multilayered anisotropic laminate under mechanical and temperature loads. Quantitative measures of interlaminar action across interfaces may be readily obtained through purely algebraic operations, even if nonlinear and inelastic material behavior becomes significant in the boundary region due to severe strain concentration. These measures are the limiting values of the Lekhnitskii stress functions F and $$ (and of the normal derivative of F) along interfaces and toward the interior region of the laminate. In the present work, they are used as the basis of an exceedingly simple and efficient method of interlaminar stress analysis that is potentially applicable to free-edge problems involving nonlinear thermoelastic constitutive relations. Example solutions are obtained for symmetric, four-layer, cross-ply and angle-ply laminates under a temperature load and two different types of strain loads, and the results are found to be in reasonable agreement with the existing numerical and analytical solutions based on elaborate analysis methods.

scholarly journals Analysis of Free Edge Stresses in Composite Laminates Using Higher Order Theories

2014 ◽  
Vol 2014 ◽  
pp. 1-15 ◽  
Author(s):  
Hamidreza Yazdani Sarvestani ◽  
Ali Naghashpour
Keyword(s):  
Composite Laminates ◽  
High Efficiency ◽  
Single Layer ◽  
Free Edge ◽  
Higher Order ◽  
Design Guidelines ◽  
Computational Time ◽  
Interlaminar Stresses ◽  
Layerwise Theory ◽  
Free Edges

This paper presents the determination of the interlaminar stresses close to the free edges of general cross-ply composite laminates based on higher order equivalent single-layer theory (HESL). The laminates with finite dimensions were subjected to a bending moment, an axial force, and/or a torque for investigation. Full three-dimensional stresses in the interior and the boundary-layer regions were determined. The computed results were compared with those obtained from Reddy’s layerwise theory. It was found that HESL theory predicts precisely the interlaminar stresses near the free edges of laminates. Besides, high efficiency in terms of computational time is obtainable when HESL theory is used as compared with layerwise theory. Finally, various numerical results were presented for the cross-ply laminates. Also design guidelines were proposed to minimize the edge-effect problems in composite laminates.

scholarly journals Investigation of the Free Edge Interlaminar Stresses Dependence on the PLY Thickness and Orientation

2006 ◽  
Vol 15 (1) ◽  
pp. 096369350601500
Author(s):  
Dionisios T. G. Katerelos
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Composite Laminates ◽  
Free Edge ◽  
Thermomechanical Loading ◽  
Interlaminar Stresses ◽  
Element Analysis ◽  
3 Dimensional ◽  
Out Of Plane ◽  
Dimensional Finite Element

Among the principal damage modes in composite laminates, is delamination. Design details, such as free, straight or curved, edges, induce large local out-of-plane loads, generating interlaminar stresses. In the present work, the effect of ply thickness and the angle between two adjacent layers on the interlaminar stresses developed at the vicinity of straight and curved free edges in composite laminates under thermomechanical loading is examined. The results are obtained by the application of a 3-dimensional Finite Element Analysis.

scholarly journals Series Solution-Based Approach for the Interlaminar Stress Analysis of Smart Composites under Thermo-Electro-Mechanical Loading

Mathematics ◽  
2022 ◽  
Vol 10 (2) ◽  
pp. 268
Author(s):  
Salman Khalid ◽  
Jaehun Lee ◽  
Heung Soo Kim
Keyword(s):  
Mechanical Loading ◽  
Composite Laminates ◽  
Composite Structures ◽  
Series Solution ◽  
Eigenvalue Problems ◽  
Virtual Work ◽  
Coupling Effect ◽  
Free Edge ◽  
Smart Composite ◽  
Interlaminar Stresses

This paper introduces a new loading condition considering the combined thermo-electro-mechanical coupling effect in a series solution-based approach to analyze the free-edge interlaminar stresses in smart composite laminates. The governing equations are developed using the principle of complementary virtual work. The assumed stress fields satisfy the traction-free and free-edge boundary conditions. The accurate stress states of the composite structures are acquired through the procedure of generalized eigenvalue problems. The uniform temperature is employed throughout the laminate, and the electric field loading is applied to the symmetric piezo-bonded actuators to examine the combined effect of thermal and electrical stresses on the overall deformation of smart composite laminates. It was observed that the magnitude of the peeling stresses generated by mechanical loading was reduced by the combined thermal and electric excitation loading (up to 25.3%), which in turn resulted in expanding the service life of the smart composite structures. The proposed approach is implemented on three different layup configurations. The efficiency of the current methodology is confirmed by comparing the results with the 3D finite element (FEM) solution computed by ABAQUS.

scholarly journals Evaluation of Interlaminar Stresses in Composite Laminates with a Bolt-Filled Hole Using a Linear Elastic Traction-Separation Description

2017 ◽  
Vol 7 (1) ◽  
pp. 93
Author(s):  
Yong Cao ◽  
Yunwen Feng ◽  
Xiaofeng Xue ◽  
Wenzhi Wang ◽  
Liang Bai
Keyword(s):  
Composite Laminates ◽  
Interlaminar Stresses ◽  
Linear Elastic

Damage Control in Composite Laminates

2001 ◽  
Author(s):  
Alexander P. Suvorov ◽  
George J. Dvorak
Keyword(s):  
Composite Laminates ◽  
Composite Laminate ◽  
Damage Control ◽  
Thermomechanical Loading ◽  
Interlaminar Stresses ◽  
Damage Resistance ◽  
Viscoelastic Composite ◽  
Mechanical Loads ◽  
Composite Damage ◽  
The Matrix

Abstract Several effects that fiber prestress may have on stress redistribution in the plies of composite laminates and in the phases of individual plies are illustrated. These include improvement of composite damage resistance under tensile mechanical loads, reduction/cancelation of interlaminar stresses at free edges of composite laminate subjected to thermomechanical loading, and stress relaxation in the matrix phase of viscoelastic composite laminates. Specific results are found for quasi-isotropic and cross-ply symmetric S-glass/epoxy and carbon/epoxy AS4/EPON 828 laminates.

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