Journal ArticleDOI
Interlaminar Stresses in Composite Laminates Under Uniform Axial Extension
R. Byron Pipes,N. J. Pagano +1 more
TLDR
In this article, the response of a finite-width composite laminate under uniform axial strain is treated through the application of classical elasticity theory, and finite-difference solution techniques are employed to obtain solutions for stresses and displacements throughout the region.Abstract:
The response of a finite-width composite laminate under uniform axial strain is treated through the application of classical elasticity theory. Finite-difference solution techniques are employed to obtain solutions for stresses and displacements throughout the region. Results for material properties typical of a high modulus graphite-epoxy composite material system are presented which explain the mechanism of shear transfer within a symmetric laminate. In addition, results of this work are compared to those given in a recent approximate formulation.read more
Citations
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Book ChapterDOI
Computational Mechanics of Failure in Composites at Multiple Scales
TL;DR: The contribution starts with a discussion of various phenomena in laminated composite structures that can lead to failure: matrix cracking, delamination between plies, and debonding and subsequent pull-out between fibres and the matrix material.
Dissertation
Three dimensional static and dy- namic analysis of hybrid plate using multi-term multi-field extended kantorovich method
Abstract: Laminated composite structures are extensively used in aerospace vehicles, marine applications, automotive and various other industries for their high specific strength, design flexibility and requiring low maintenance. These structures with embedded or surface bonded piezoelectric layers often called as smart or intelligent or hybrid structures offer additional advantage of sensing and control apart from their primary structural responsibility. The smart structures are extensively used in structural health monitoring, shape and vibration control applications, but the presence of geometric and material inhomogeneity across the layers introduce complex electromechanical couplings inducing sharp stress variations near the non-simply supported edges. So, the analysis of such structures with high accuracy demand special tools with greater computational efficiency. Three dimensional (3D) analytical solutions are the most efficient tools for analysis of smart or hybrid laminated structures which can compute the global as well as local responses more accurately. In this thesis, three dimensional extended Kantorovich method (3D EKM) is used to obtain the static and free vibration elasticity/piezoelasticity solution of hybrid rectangular laminated plates and results from two dimensional (2D) zig-zag and third order theory are assessed with respect to the 3D solutions. The generalized coupled three-dimensional piezoelasticity solution for multi-layered composite plates integrated with piezoelectric layers subjected to Levy-type boundary conditions is presented using the mixed-field multi-term extended Kantorovich method (EKM) and Fourier series expansion. A mixed formulation approach in which displacement as well as stresses are taken as state variables in the solution domain is followed. The initial functions are not required to satisfy the essential or natural boundary conditions and the solution converges very fast. The convergence and accuracy of this method is established by comparing the results with the 3D exact solution, wherever available, and with the 3D finite element (FE) solution for the rest iv TH-2037_136103018 for both pressure and potential loading cases. The anomalies and pitfalls of the FE solution in predicting stress responses at or near to the edges are pointed out. The effect of adhesive layer between the face and elastic substrate is also investigated and found that it eases out the sharp stress variations at the layer interface. The method is further extended to the free vibration analysis of finite dimensional elastic laminated plates. Results are presented for various laminate lay-ups and boundary conditions and are extensively validated by comparing with the results of other theories and 3D FE results. Benchmark natural frequencies and mode shapes are presented for laminated composite and sandwich plates. It is found that single term solution is sufficient enough for obtaining accurate natural frequencies, but stresses near the clamped edge are accurately predicted by multi-term (n=2) solution. The effect of span-to-thickness ratio and in-plane modulus ratio on the natural frequency is also studied. The effect of adhesive modulus, density and layer thickness on the free vibration behaviour of elastic laminated plates is also investigated. The 3D EKM has also been extended to investigate the free vibration behaviour of Levy-type hybrid laminated composite and sandwich plates integrated with piezoelectric actuators and sensors. The accuracy and efficacy of this method is verified thoroughly by comparing it with the existing results in the literature and FE solutions. The numerical results are presented for bimorph, hybrid composites and sandwich plates. Effect of piezo-layer thickness, electric circuit conditions and plate aspect ratios on the natural frequency are also investigated. Effect of adhesive layer on the free vibration characteristics of a bimorph plate is also investigated. Apart from the above 3D analysis, analytical solutions for the free vibration of Levytype rectangular elastic laminated plates based on efficient layerwise 2D zig-zag theory and the third order theory (TOT) are also presented. The 2D results are assessed in comparison with the 3D elasticity solution to estimate its accuracy. Further, the analysis is extended for the piezoelasticity static and free vibration solution of hybrid rectangular plates. The improved zig-zag theory (IZIGT) and its smeared counterpart, the improved third order theory (ITOT) are developed to obtain the results and are assessed for the accuracy with respect to the 3D piezoelasticity solution of 3D EKM.
Book ChapterDOI
Lamination Theory and Failure Mechanisms in Composite Shells
TL;DR: In this article, the classical lamination theory is described on the basis of Mindlin-Reissner's kinematics, and a procedure is presented for estimating local instability phenomena such as different modes of face layer wrinkling or intracell buckling and failure due to transverse normal stresses.
Journal ArticleDOI
Finite-element analysis of frictionless contact problem for a laminated medium
TL;DR: A finite-element method is developed to study interlaminar stress effects for the multilayered isotropic medium subjected to in-plane loads andVariational finite difference equations obtained from the finite- element discretization are derived for boundary as well as transmission conditions.
Journal ArticleDOI
Edge delamination in laminated composites
TL;DR: A damage evolution theory for the effects of the rather complicated edge delamination phenomena on composite laminate response is developed in this article, which is a mechanics-based formulation which quantifies the damage development of a laminate under general loading, and incorporates it directly into the laminate constitutive equations.
References
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Journal ArticleDOI
Theory of Elasticity of an Anisotropic Elastic Body
Journal ArticleDOI
Edge-Bonded Dissimilar Orthogonal Elastic Wedges Under Normal and Shear Loading
Journal ArticleDOI
Bending and Stretching of Certain Types of Heterogeneous Aeolotropic Elastic Plates
Eric Reissner,Y. Stavsky +1 more
Journal ArticleDOI
Interlaminar Shear in Laminated Composites Under Generalized Plane Stress
A.H. Puppo,H.A. Evensen +1 more
TL;DR: In this article, an analysis of interlaminar shear stresses is performed for a laminate under generalized plane stresses, where the laminate is modeled as a set of anisotropic layers separated by isotropic adhesive layers.
Related Papers (5)
Some New Results on Edge Effect in Symmetric Composite Laminates
A.S.D. Wang,Frank W. Crossman +1 more
Boundary-Layer Effects in Composite Laminates: Part 1—Free-Edge Stress Singularities
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Interlaminar Shear in Laminated Composites Under Generalized Plane Stress
A.H. Puppo,H.A. Evensen +1 more