Harkati el-haddi

Université de Tébessa · génie civil

Stress concentrations pose a significant challenge in designing and optimizing composite components, often resulting in structural alterations and crack formation. This study delves into a detailed numerical and analytical analysis of stress concentration factors in composite materials, with a specific focus on the influence of negative Poisson's r...

Waste rock materials are becoming widely used in road pavement and building constructions in many countries. In this work, experimental laboratory tests were carried out on the waste rock produced from the extraction of the phosphate in the Kef-Essenoun mine, to study the performance of road pavement foundations built with these types of material....

Underground mining operations are a very problematic task, especially in poor geotechnical conditions. The right choice of excavation and support techniques leads to adequate and secure mining operations. This should ensure the overall stability of the underground mine with the best productivity and stability performance. In this paper, an empirica...

In this work, the nonlinear time history response and dynamic-buckling of functionally graded material (FGM) shell structures in thermal environments with temperature-dependent material properties are studied. The effective properties of the functionally graded material are assumed to be temperature-dependent and can vary through the thickness only...

In this paper, the nonlinear time history response and dynamic-buckling of functionally graded material (FGM) shell structures in thermal environments with temperature-dependent material properties is studied. An implicit conservative/decaying time integration scheme and a curved 8-node degenerated shell element are used for time and spatial discre...

Nonlinear geometrically static response of functionally graded ceramic-metal plate-shell structures under mechanical loading is investigated. Material properties are assumed to vary through the thickness direction according to the power law distribution of the volume fraction of the constituents. The incremental equilibrium equation is obtained usi...

In this paper, the modal capacities of the honeycomb sandwich plates with a viscoelastic core are analysed using a finite element model developed in ABAQUS. The viscoelastic material used for the basic material of the honeycomb core is defined using a Prony series corresponding to the Maxwell model. The modal frequencies analysis has shown that the...

The work describes the out-of-plane properties of a curved wall honeycomb structure evaluated using analytical models and finite elements techniques. Out-of-plane properties are calculated using a theoretical approach based on energy theorems and validated using a full-scale finite element technique to simulate transverse shear tests. The effects o...

La concentration de contraintes dans les pièces composites est un problème souvent rencontré dans la conception mécanique. C'est un phénomène d'augmentation locale des contraintes dans une zone comportant une modification géométrique de la pièce. Cette zone est souvent le site d'amorçage des fissures et peut être l'origine d'une rupture brutale. L'...

This paper is focused on the identification of the in-plane elastic constants of a new design of auxetic (negative Poisson's ratio) honeycomb configuration with curved cell walls by using analytical and numerical homogenization techniques. The sensitivity of the elastic constants is determined against the various cell geometry parameters. Good agre...

lateral Torsional Buckling (LTB) is a mode of buckling that occurs when a flexural member undergoes both lateral deflection and twisting. However, the complex nature of the LTB phenomenon makes it hard to embrace all the affecting factors and assumptions. The LTB capacity of a slender section depends upon a number of variables influencing the resis...

In this article, analytical and numerical models are proposed to describe the auxetic behavior of hexagonal honeycomb structures with curved walls. To do this, a comparative study between a conventional and auxetic honeycomb structure having respectively a positive and negative Poisson's ratio compared to hexagonal structure. The cellular structure...

The quick emergence of composites since their invention due to their high specific properties do not gainsay the health problems associated with the use of synthetic fibers as reinforcing agent of almost all commercially available polymer composites. To avoid those hazardous effects, the current global tendency is the incorporation of lignocellulos...

Over the past several years, extensive theoretical, numerical and experimental research has been carried out on the structural behavior of steel beams with web openings of various shapes. However, in all these studies, cellular beams have always been treated or designed as simply supported at their ends. In other words, the beam to column connectio...

Growing environmental protection consciousness has revived the interest to develop eco-friendly composites fibers from bio-renewable resources due to their unique intrinsic properties and their wide applications. Thus, in the last two decades, extraction and use procedures of natural fibers have known an important increase for the reinforcement of...

Purpose The purpose of this paper is to study the effect of the relative density and geometric parameters on the homogenised in-plane elasticity modulus of a cellular honeycomb structure using analytical and numerical approaches. Design/methodology/approach In this work, the mechanical behaviour of a new design of the honeycomb is analysed throu...

We propose in this paper analytical and numerical models that describe the in-plane uniaxial elastic properties (Young's moduli and Poisson's ratios) of a honeycomb structure with curved walls. We perform a parametric analysis of the mechanical performance of this honeycomb also by taking into account the different types of deformations acting insi...

We propose in this paper analytical and numerical models that describes the in-plane uniaxial elastic properties (Young's moduli and Poisson's ratios) of a honeycomb structure with curved walls. We perform a parametric analysis of the mechanical performance of this honeycomb also by taking into account the different types of deformations acting ins...

The last decades of the XXe century cognized a huge extent of composite materials uses to almost all everyday life's applications, replacing the conventional materials, due to their outstanding properties especially highest strength-to-weight ratio and the ability to be designed to satisfy specific performance requirements. To get the most out of t...

Honeycomb structures are essentially constituted of a repetition of regularly-arranged and loaded sub-structures. The present study carries out a parametrically investigation of the behavior of a multi re-entrant honeycomb structure with variable stiffness and Poisson’s ratio effects. A refined analytical model is specifically developed and compare...

In the two last decades, extraction and use procedures of natural fibers have known an important increase for the reinforcement of composite materials called ‘Bi-composites’. This category of fibers possesses a lot of advantages upon those traditional synthetic such as: Abundantly available, reduced cost, lightness and satisfactory specific perform...

This work is concerned with the influence of carbon fibre, resin types and fibre volume fraction on the through the thickness Poisson's ratio of composite laminates. Different types of carbon fibres in various resins with several fibre volume fractions ranging between 65 and 80% are analysed to show the effect of each parameters on the values of th...

Most of usual materials exhibit Poisson's ratio comprised between 0 and 0.5. But, for some kind of cellular materials, or for some stacking sequences of unidirectional plies, a composite material can exhibit negative or greater than 0.5 Poisson's ratios. In this paper, a study of different stacking sequences such as [±ß/±θ]s plies made from highly...

We describe the effect of the stacking sequence on the distribution of the deformation and stress fields through the thickness of the laminate. The laminates are made of epoxy resin and glass fibres, having the ratio of 0 to 90� plies equal to 1. This stacking sequence is applied to obtain composite laminates with different thicknesses. The study p...

The authors discuss the use of an artificial neural network (ANN) to estimate fatigue lifetime of a sandwich composite material structure subjected to cyclic three-point bending loads. A total of 27 samples (three different loading levels for nine samples each) were investigated to provide training, validation and testing data for a series of multi...

The variation of through-thickness Poisson's ratio with fibre type and orientation has been investigated using a specially developed Fortran program. Glass fibre/epoxy resin composites were always found to be conventional, but negative Poisson's ratio values of up to ν13 = –0.746 were produced over certain orientation angles for Kevlar and carbon r...