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Stress and failure analysis of composite plates with circular hole subjected to shear loading. Part 1, Analytical and finite element formulation

Khechai Abdelhak, Tati Abdelouahab, Belarbi Mohamed-Ouejdi, Rekbi Fares Mohammed Laid

Composites Theory and Practice

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2022

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R. 22, nr 4

205--210

EN

This current paper, which is the first part of two parts of a complete article, presents the theoretical and finite element formulation developed and proposed by the authors to obtain the stress concentration factors (SCFs) and the first ply failure (FPF) loads of composite laminated plates. The numerical studies are performed using a quadrilateral finite element of four nodes with thirty-two degrees of freedom. The present finite element was previously developed by the authors to study the bending and buckling of composite plates. The present finite element is a combination of two finite elements. The first one is a linear isoparametric membrane element, and the second one is a high-precision rectangular Hermitian element. In the second part of the paper, several examples will be considered to demonstrate and affirm the accuracy and the performance of the present element, as well as highlight the effect of some parameters on the stress distribution. The FPF strengths and their locations in laminated plates with and without holes are calculated by adapting the Hashin-Rotem, Tsai-Hill, and Tsai-Wu failure theories.

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Stress and failure analysis of composite plates with a circular hole subjected to shear loading. Part 2, Results and discussions

Khechai Abdelhak, Tati Abdelouahab, Belarbi Mohamed-Ouejdi, Rekbi Fares Mohammed Laid

Composites Theory and Practice

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2022

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R. 22, nr 4

225--232

EN

This paper, the second part of two parts of a complete paper, presents the analytical and numerical results of stresses around circular cutouts in anisotropic and isotropic plates under shear loading. The main aim of this study is to understand the effect of the presence of cutouts on the stress concentration and failure mechanisms in composite laminates. The numerical investigations are performed by means of the quadrilateral finite element of four nodes with thirty-two degrees of freedom. The present finite element is a combination of two finite elements. The first one is a simple linear isoparametric membrane element and the second one is a high-precision rectangular Hermitian element. The analytical and finite element formulations were presented in the first part of the paper. Several new examples are considered to demonstrate and affirm the accuracy and the performance of the present element and to highlight the effect of some parameters on the stress distributions. The numerically obtained results are found to be in good agreement with the analytical findings. On the other hand, first ply failure (FPF) strengths in laminates with and without holes are calculated by adapting the Hashin-Rotem, Tsai-Hill, and Tsai-Wu failure theories. Finally, the numbers of the figures are obtained, using various E1/E2 ratio values, for the maximum positive and negative stresses values located in the vicinity of the cutout versus the angular location of points, and for various fiber orientation angles.

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Critical state constitutive models and shear loading of overconsolidated clays with deviatoric hardening

Rachdi Sara, Jahangir Emad, Tijani Michel, Serratrice Jean-François

Studia Geotechnica et Mechanica

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2019

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Vol. 41, nr 4

247--262

EN

This paper presents an enhanced constitutive model integrating deviatoric hardening with a modified yield surface for overconsolidated clayey soils in a general framework of Cam-clay type models. Its performance was assessed with the simulation of drained and undrained triaxial tests on three clays at different consolidation states in comparison to two critical state models. The proposed model satisfactorily estimates the shear resistance, while capturing the smooth nonlinearity of the soil response. Shear triaxial tests at constant mean pressure were performed on an overconsolidated marl to study the shear response. Their simulation attests the importance of deviatoric hardening integration.

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Stresses in coating with gradient interlayer caused by contact loading

Kulchytsky-Zhyhailo R., Bajkowski A.

Acta Mechanica et Automatica

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2014

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Vol. 8, no. 1

33--37

EN

The three-dimensional problem of elasticity concerning inhomogeneous half-space under normal and tangential loading applied in circular region was considered. The half-space is composed of the homogeneous body and double-layer coating which includes a homogeneous top coat and a gradient interlayer. The solution method is based on the two-dimensional integral Fourier transform. The influence of mechanical properties of coatings component and coefficient of friction on the first principal stress distribution was considered.

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Stress distribution in a composite coating by local loading of the free surface

Kulchytsky-Zhyhailo R., Kołodziejczyk W.

Acta Mechanica et Automatica

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2014

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Vol. 8, no. 2

83--87

EN

A three-dimensional problem of the theory of elasticity for halfspace with multilayered coating with periodical structure is consid-ered. The fundamental layer consists of two layers with different thicknesses and different mechanical properties. The coating is described by the homogenized model with microlocal parameters. The solution is derived by using integral Fourier transform. Calculations were con-ducted with the assumption of elliptical distribution of normal and tangential tractions applied to the surface of the layered system in a cir-cular area. Analysis of the stresses was restricted to the first principal stress distribution.