Catégorie B

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Plane Stress Fracture Toughness of Unplasticized PVC Material Determined by the Essential Work of Fracture (EWF) Approach
(World Applied Sciences Journal, 2015) Belhamiani, M; Benguediab, M
Essential work of fracture (EWF) approach was used to evaluate the fracture toughness of uPVC film. It was found that the specific essential work of fracture, (we) is independent of specimen width, specimen gauge length, loading rate and test temperature, but dependent on the geometry of the test specimens. Test temperature and geometry were the only testing parameters affecting the specific non-essential work of fracture ( wp) in a very significant way. This approach has proved to be capable of determining toughness and to illustrate the crack grow from DENT specimen. This difference was confirmed by the high ductility and the development of the necking zone at the crack tip under two different conditions (Plan strain and plane stress). The present work is aimed at studying the response and ligament length effects on the fracture behaviour of a amorphous polyvinyl chloride - Pipe. The evaluation of toughness under plane stress conditions was performed by this method. The results are examined and discussed in terms of recent developments.
INVESTIGATING THE EFFECTS OF CRACK ORIENTATION AND DEFECTS ON PIPELINE FATIGUE LIFE THROUGH FINITE ELEMENT ANALYSIS
(2023) Kebir, Tayeb; Belhamiani, Mohamed; Daikh, Ahmed Amine; Benguediab, Mohamed; Benachour, Mustapha
In response to the steady rise in global demand for energy resources such as gas and oil, there is a pressing need to enhance the efficiency and safety of pipeline transportation systems. These systems, integral for transferring vast amounts of energy, must operate under increasingly higher pressures and larger diameters without compromising reliability. This study focuses on utilizing finite element analysis (FEA) to investigate the influence of crack orientation and the presence of defects on the fatigue life of pipelines. By simulating internal pressure scenarios and examining various defect characteristics with the AFGROW software, this research applies damage tolerance principles to offer insights into the fatigue behavior of pipelines. The findings can be applied to extend the operational life and ensure the integrity of these critical infrastructures, thereby supporting the sustainable and safe transport of energy resources.
Failure behavior of a notched plate repaired by a hybrid repair technique (Stop hole bonded composite
(2023) BELHAMIANI, Mohamed; Djebbar, Noureddine; Oudad, Wahid; Bouzitouna, Wahiba Nesrine
Generally, bonded repairs are only approved if the primary aircraft structure is cracked and the residual strength significantly exceeds the design limit charge before the bonded repair can be applied.. In order to improve the maintenance effect of the stop hole approach for cracks, a solution of using both techniques (stop hole / bonded composite repairs) are proposed and investigated by finite element analysis. This work presents a study on the effectiveness of the hybrid repair technique in notched panels using both stop drilling hole and bonded composite repair techniques. Several parameters are taken into account: the diameter of the size of hole drilling, the width and the thickness of the composite patch and other parameters are modeled with a elastoplastic behavior of the plate using Abaqus software. A limit-load analysis determines a lower bound to the limit charge of a component and provides an alternative way to estimate plastic collapse for the limit loads. In addition, the limit load analysis had helped to provide an evaluation of the behaviors of structures or components for other failures. The plastic limit load (PLL) was evaluated by a convergent load increment in a wellconfigured finite element analysis with a load of a sufficiently small increment for an elastic-perfectly plastic behavior of the structure. The allowable limit stress on the aircraft is calculated by applying design factors to the plastic limit load (PLL) so that the onset of plastic collapse does not occur. The results proved that the hybrid repair provided the largest percentage in terms of maintenance and the smallest values for the notch stress intensity factor (NSIF) and von Mises stress for most of the hybrid configuration compared to the single repair technique.
The Effect of Operating Parameters on Total Cross-membrane Flux in a PVDF Flat Sheet Membrane
(Periodica Polytechnica Chemical Engineering, 2023) Bekraoui, Hafsa; Nehari, Driss; Baki, Touhami; Bousmaha, Mouad
Membrane distillation (MD) is an emerging thermal membrane technology that involves water vapor driven by a vapor pressure gradient over a hydrophobic membrane. MD faces several challenges, one of which is the flux of water vapor. The total cross-membrane flux in membrane distillation was investigated in this paper using the co-current PVDF flat sheet for direct contact. membrane distillation applications. The goal of this research is to improve total cross-membrane flux. The effect of various operational parameters is studied, including feed inlet temperature (333.15–358.15 K), feed flow rate (1–2.5 kg/s), permeate inlet temperature (288.15–313.15 K), and feed inlet NaCl concentration (0.035 to 0.485 kg/kg). To acquire a good value of total cross-membrane flux, their interactions with the total cross-membrane flux are studied in this work. The obtained results were computed during MATLAB-Simulations under several scenarios adopting the Trial-&-Error approach. This last inputs various parameters' values and thus draws the required curves to be discussed and analyzed. The results indicated that the PVDF flat sheet membranes provide a significantly higher total cross-membrane flux at higher feed input temperatures, producing a 73.2075 kg/(m2 h) at a feed inlet temperature of 358.15 K, a permeate inlet temperature of 293.15 K, and a flow rate of 2.5 kg/s, with a feed inlet NaCl concentration of 0.035 kg/kg. Feed inlet temperature significantly affected the total flux through the membrane; however, flow rate, permeate inlet temperature, and feed inlet NaCl concentration had a less significant effect.
Application of the IRAP Method Combined with GIS to Improve Road Safety on New Highway Projects in Algeria
(Periodica Polytechnica Transportation Engineering, 2022) Derras, Abdelhak; Amara, Khaled; Oulha, Ramdane
This article aims to proactively predict high-risk accident areas in a new highway project in terms of its technical and geometric characteristics. The purpose of this study is to provide road project managers with better road safety assessment tools for the vehicle occupant category. The methodology used combines the International Road Assessment Program (IRAP) methodology and the Geographic Information System (GIS). The IRAP program enables the calculation and classification of risks for each 100-meter segment besides their categorization using a star rating; whereas, the GIS is used to map the risks and identify high-risk accident segments. This method was applied to a new highway project of 110 hectometres located in GHAZAOUET in Algeria. The results of the study revealed that this combined method is innovative in more than one way as it is an effective decision-making aid tool for road safety experts. It, therefore, makes it possible to target accident-prone sections in a faster way before carrying out on site road safety inspections. Technically speaking, this study shows that the existence of closely curved radii mixed at traffic speeds exceeding 80 km/h and the presence of road exits are the main factors affecting the safety of vehicle occupants. Speed control; thus, remains one among the cheapest measures to improve safety
The Effect of Operating Parameters on Total Cross-membrane Flux in a PVDF Flat Sheet Membrane
(Periodica Polytechnica Chemical Engineering, 2023) Bekraoui, Hafsa; Nehari, Driss; Baki, Touhami; Bousmaha, Mouad
Membrane distillation (MD) is an emerging thermal membrane technology that involves water vapor driven by a vapor pressure gradient over a hydrophobic membrane. MD faces several challenges, one of which is the flux of water vapor. The total cross-membrane flux in membrane distillation was investigated in this paper using the co-current PVDF flat sheet for direct contact. membrane distillation applications. The goal of this research is to improve total cross-membrane flux. The effect of various operational parameters is studied, including feed inlet temperature (333.15–358.15 K), feed flow rate (1–2.5 kg/s), permeate inlet temperature (288.15–313.15 K), and feed inlet NaCl concentration (0.035 to 0.485 kg/kg). To acquire a good value of total cross-membrane flux, their interactions with the total cross-membrane flux are studied in this work. The obtained results were computed during MATLAB-Simulations under several scenarios adopting the Trial-&-Error approach. This last inputs various parameters' values and thus draws the required curves to be discussed and analyzed. The results indicated that the PVDF flat sheet membranes provide a significantly higher total cross-membrane flux at higher feed input temperatures, producing a 73.2075 kg/(m2 h) at a feed inlet temperature of 358.15 K, a permeate inlet temperature of 293.15 K, and a flow rate of 2.5 kg/s, with a feed inlet NaCl concentration of 0.035 kg/kg. Feed inlet temperature significantly affected the total flux through the membrane; however, flow rate, permeate inlet temperature, and feed inlet NaCl concentration had a less significant effect.
Mechanical and morphological characterization of recycled HD-PE bio-composites based on alfa fibers and natural pozzolan
(J Polym Eng, 2022) Achour, Bouchra; Ziadi, Abdelkader; Belarbi, Lahcen; Mokaddem, Allel; Lousdad, Abdelkader
In this research work, waste plastic bottle caps made of high-density polyethylene (HD-PE) were reincorporated as a matrix and reinforced by alfa short fibers and natural pozzolan particles. Using different weight percentages of both fillers of 5 wt% up to 30 wt%, three types of biocomposite materials have been produced; alfa short fibers/ HDPE, pozzolan particles/HDPE, and alfa fibers pozzolan/ HDPE. Specimens for each type of the biocomposites were prepared through the compression molding method. The objective of this study is to investigate the effect of different content of alfa short fibers and pozzolan particles on the mechanical and morphological properties of the recycled HDPE matrix. Tensile test results revealed an enhancement in the mechanical properties for the three types of the biocomposites, an increase in tensile strength reached the maximum of 3573 MPa plus an interesting improvement in Young’s modulus with a maximum value of 3696 MPa. The toughness of the neat recycled HD-PE decreased by 212% by adding the natural filler whereas the modulus of resilience exhibited an increase of 138% compared to the neat recycled HD-PE. Therefore, the good rheological behavior of these bio-composites makes it possible to produce competitive materials and allows the reduction of plastic waste in the environment.
IMPACT OF VARIABLE PASSAGE SECTION AND ZIGZAG ABSORBER ON THE THERMAL PERFORMANCE OF A THERMO-SOLAR CONVERTER FOR DRYING
(Journal of Theoretical and Applied Mechanics, 2022) BOUDJEMA, FETHI MOUSSA; BENZENINE, HAMIDOU
This paper presents a numerical study of a two-dimensional laminar airflow transferred in a thermo-solar collector with forced convection. Simulations were processed to determine and analyze the dynamic and thermal fields under the influence of variation of collector configuration. Two cases of collector geometry (model of narrowing at exit and model of widening at entry) were studied and compared to the simple case uniform solar collector based on variations in temperature and velocity at the collector outlet for an input velocity varying between 0.04 and 0.11 m/s. The results show that the collector equipped with a zigzag-shaped absorber with a narrowing of the section at the outlet or widening at the inlet contribute to the thermal and dynamic improvement of the flow in the air stream compared with a simple case. The best performing case is recorded for the narrowest case of the exit shrinkage model where the exit velocity has been increased by 250%. this velocity reduces the drying time and increases the efficiency of the evacuation of the humid air leaving the chamber.
Formulation and evaluation a finite element model for free vibration and buckling behaviours of functionally graded porous (FGP) beams
(Structural Engineering and Mechanics, 2023) Mesbah, Abdelhak; Belabed, Zakaria; Amara, Khaled; Touns, Abdelouahed; Bousahla, Abdelmoumen; Bourada, Fouad
This paper addresses the finite element modeling of functionally graded porous (FGP) beams for free vibration and buckling behaviour cases. The formulated finite element is based on simple and efficient higher order shear deformation theory. The key feature of this formulation is that it deals with Euler-Bernoulli beam theory with only three unknowns without requiring any shear correction factor. In fact, the presented two-noded beam element has three degrees of freedom per node, and the discrete model guarantees the interelement continuity by using both C0 and C1 continuities for the displacement field and its first derivative shape functions, respectively. The weak form of the governing equations is obtained from the Hamilton principle of FGP beams to generate the elementary stiffness, geometric, and mass matrices. By deploying the isoparametric coordinate system, the derived elementary matrices are computed using the Gauss quadrature rule. To overcome the shear-locking phenomenon, the reduced integration technique is used for the shear strain energy. Furthermore, the effect of porosity distribution patterns on the free vibration and buckling behaviours of porous functionally graded beams in various parameters is investigated. The obtained results extend and improve those predicted previously by alternative existing theories, in which significant parameters such as material distribution, geometrical configuration, boundary conditions, and porosity distributions are considered and discussed in detailed numerical comparisons. Determining the impacts of these parameters on natural frequencies and critical buckling loads play an essential role in the manufacturing process of such materials and their related mechanical modeling in aerospace, nuclear, civil, and other structures.
Flexural and free vibration responses of thick isotropic bridge deck using a novel two variable refined plate theory
(Structural Engineering and Mechanics, 2022) Djidar, Fatima Zohra; Hebali, Habib; Amara, Khaled; Touns, Abdelouahed; Bendaho, Boudjema; Ghazwani, M.H.; Hussain, Muzamal
This work presents a simple exponential shear deformation theory for the flexural and free vibration responses of thick bridge deck. Contrary to the existing higher order shear deformation theories (HSDT) and the first shear deformation theory (FSDT), the proposed model uses a new displacement field which incorporates undetermined integral terms and involves only two variables. Governing equations and boundary conditions of the theory are derived by the principle of virtual work. The simply supported thick isotropic square and rectangular plates are considered for the detailed numerical studies. Results of displacements, stresses and frequencies are compared with those of other refined theories and exact theory to show the efficiency of the proposed theory. Good agreement is achieved of the present results with those of higher order shear deformation theory (HSDT) and elasticity theory. Moreover, results demonstrate that the developed two variable refined plate theory is simple for solving the flexural and free vibration responses of thick bridge deck and can achieve the same accuracy of the existing HSDTs which have more number of variables.
A Numerical Study for Determining the Effect of Raffia, Alfa and Sisal Fibers on the Fiber-matrix Interface Damage of Biocomposite Materials
(2021) Achour, Bouchra; Mokaddem, Allel; Bendouma, Doumi; Ziadi, Abdelkader; Belarbi, Lahcen; Boutaous, Ahmed
LOW COST SDR RECEIVER IMPLEMENTATION USING RTL-SDR DONGLE
(Telecommunications and Radio Engineering, 2019) Yagoub, Reda; Benadda, B; Benaissa, Mohammed; Taleb-Ahmed, A; Lahouel, A; Zane, F
The advent of Software Defined Radio (SDR) has made it possible to replace large parts of classical radio communication equipment with digital and software components to easily achieve configurable and multiplatform communication systems. SDR provides many advantages for research and development. In this work, the low-cost Realtek Software Defined Radio (RTL-SDR) dongle can serve as a cheap SDR platform to receive and digitize exchanged RF signals. In case of RTL-SDR dongle, in-phase and quadrature samples (I/Q) are sent as a stream through simple Universal Serial Bus interface (USB) to host computer. This paper describes a SDR application that can be used for many functionalities such as monitoring and scanning of frequency bands with RTL-SDR dongle.
Stress intensity factors analyses for external semi-elliptical crack for repaired gas-pipeline by composite overwrap under pressure
(Frattura ed Integrità Strutturale (Fracture and Structural Integrity), 2019-06-26) Belhadri, Djamel Eddine; Belhamiani, Mohamed; Bouzitouna, Wahiba Nesrine; Oudad, Wahid
The purpose of this article is to present the stress intensity factors (SIF) solutions for semi-elliptic crack in pipelines under internal pressures, the stress intensity factors are calculated by the three-dimensional finite element method (FEM) for cracked pipelines and repaired pipe by composite patch. The distribution of normalized stress intensity factors (KI, KII and KIII) along the crack front for different crack lengths, crack depth, crack geometry, lap length and composite thickness was obtained by nodal calculations. Our results show the presence of three failure modes along the semi elliptical crack front and has three zones in which the stress intensity factor in mixed mode (KII) the higher-values comparing to KI and KIII. It can also be noted that the composite repair reduces the SIF KI by 46% and the KII by 55% and the KIIIby 72% near the outside diameter of the pipe in each zone. However, the reduction of the SIF KI is more significant for the rectangular crack than for the semi-elliptic crack, from which it is concluded that the composite repair is very effective for a rectangular crack with respect to the semi-elliptic crack. Thereby, the fracture behavior of the semi-elliptic crack is governed by the three modes of failure and not only by mode I.
J integral computation and Limit load analysis of bonded composite repair in cracked pipes under pressure
(Frattura ed Integrità Strutturale (Fracture and Structural Integrity), 2019-09-12) Mohamed Belhamiani; Wahid Oudad; Wahiba Nessrine Bouzitouna
In this paper, an additional criterion was introduced to evaluate the composite repair systems using the limit load analysis. The plastic collapse pressure of API 5L X65 PSL2 steel pressure vessel structure with crack defect is numerically investigated after the structure was been repaired by composite overwrap. The objective of this study was the analysis of the efficiency of composite repair systems using this additional criterion to gain more confidence on it taking into account, the cracks and the overwrap geometries. The material of the pipe is elastic perfectly plastic for the plastic collapse pressure criterion and elastic-plastic using the Romberg Osgood model for fracture mechanic criterion. The additional criterion allows us to compare the uncracked and cracked pipe to estimate the repair efficiency. Moreover, the composite overwrap could restore 90% of the plastic collapse pressure for cracked pipes.
Numerical Analysis of Polymeric Thin Films Fracture Based on Energetic Approach "The Essential Work of Fracture
(PERIODICA POLYTECHNICA MECHANICAL ENGINEERING, 2019-11-04) Belhamiani, Mohamed; Benguediab, Mohamed; Oudad, Wahid
Actually, polymeric materials are widely used in industry due to their attractive properties. These materials are replacing the traditional materials used to manufacture mechanical components. Thus, their mechanical behavior should be known for a better and judicious use of the material. Fracture mechanics principles and tools are used to characterize polymeric thin films fracture. In this paper a global energetic approach proposed to characterize the rupture phenomenon and determine the essential work of fracture.
Probabilistic Analysis for Estimating the Hydrogen Desorption Time from Steel Wire Rods Using Monte Carlo Simulation
(Annales de Chimie - Science des Matériaux Vol. 43, No. 4, August, 2019, pp. 241-248, 2019-09-28) Ourrad, Soumia; Houmadi, Youcef; Ziadi, AbdelKader; Aissa Mamoune, Sidi Mohammed; Lousdad, Abdelkader
This study investigated the effect of hydrogen on reduction in area in relation to the storage time of a high carbon steel wire for C-Mn pre-stressed concrete in the context on hydrogen embrittlement of steel. The Monte Carlo Simulation method was employed for the probabilistic analysis. The concentration of hydrogen "C∞", the effective diffusion coefficient "De" these parameters were considered as random fields. The probabilistic response considered in the analysis was the reduction in area "Z". Numerical simulations that make use of second Fick’s law were used for the computation of this response. A parametric study was undertaken to investigate the effect of the input and the statistical parameters of the random variables on the probability distribution functions of the response. Also, this study contributes to bring more elements of comprehension on the spatial and temporal variability of the input and output parameters
Probabilistic Analysis for Estimation of the Initiation Time of Corrosion
(Mathematical Modelling in Civil Engineering Vol. 15‐No. 2: 1‐13‐201, 2019-08-02) Wafa Nor El Houda, Cherifi; Youcef, Houmadi; Benali, Omar
In this paper, a probabilistic study on durability concrete was carried out. In such a design,initiation time of corrosion must be expressed as a mathematical model using Fick’s second law andthe statistical distributions properties of theirs parameters was included in this model. The scatterboth in the environmental exposure conditions and structural properties was considered as randomfields in the mathematical model with a probabilistic design. The main objective of this study ispredicted initiation time of corrosion of concrete structures in chloride containing environments. Thisprobabilistic study is developed using Monte Carlo simulation to determine the contribution of eachinput parameters and the statistical parameters of the random variables on the probability distributionfunctions of the initiation time of corrosion. Also, a comparison study was carried out to analyze theimpact of the probability distribution on the response (the initiation time of corrosion
Local oscillator frequency offset estimation for low cost sdr receiver
(Telecommunications and Radio Engineering, 2019) Yagoub, Reda; Benaissa, Mohammed; Benadda, Belkacem; Taleb Ahmed, Abdelmalik
There are currently many low cost software defined radio (SDR) receivers in the market such as RTL-SDR dongles. These devices can be used to receive the radio frequency (RF) signals in the range of their tuners (front-end). The stability and the accuracy of the local oscillator (LO) among the important aspects that can be affect the performance of SDR receivers. This paper describes a method based GSM signals can be used to determine the frequency offset of the RTL-SDR dongles on MATLAB environment. The developed tool is evaluated using two popular RTL-SDR dongles models with and without temperature controlled local oscillator (TCXO).
Finite difference probabilistic slope stability analysis based on collocation-based stochastic response surface method (CSRSM)
(Innovative Infrastructure Solutions | Issue 3/2020, 2020-07-01) Ghedjati, Samir; Lamara, Mohammed; Houmadi, Youcef
Significant damage has been observed due to the landslide along the East–West motorway section, located near Ain Bouzian–El-Harrouch region, Northeast Algeria. In this paper, a probabilistic study was carried out to assess the stability of a slope, with a total height of 60 m and varying inclination angles. Two cases were considered with and without the presence of the groundwater table. To investigate the failure probability of the slope, the collocation-based stochastic response surface method was employed. The input random parameters were the Young modulus E, cohesion C, and friction angle φ, where probabilistic system response is the factor of safety. To identify the effective contribution of each random parameter in the variability of the system response, a global sensitivity analysis based on Sobol indices was conducted. Also, a parametric study was realized to inspect the effect of input geotechnical parameter variations on the reliability of slope stability. The result showed that the slope reliability analysis is strongly influenced by the inherent variability of friction angle and hydrogeological ground conditions.
Fracture Toughness Characterization of High-Density Polyethylene Using Essential Work of Fracture Concept
(Journal of Failure Analysis and Prevention volume 20, pages315–322 (2020), 2020-01-27) Houari, Tarek; Benguediab, Mohamed; Belaziz, Azzeddine; Belhamiani, Mohamed; Aid, Abdelkrim
In this paper, the concepts of fracture mechanics are used to determine experimentally the work essential to fracture in high-density polyethylene (HDPE) pipes. The tests were carried out on DENT specimens taken from HDPE pipes intended for the distribution of water. The monotonic mechanical characteristics of this material for two strain rates 0.1 and 0.01 s−1 show that the curves obtained are typical of semicrystalline polymers. Their shape shows that the fracture is ductile for this type of polymeric material with plasticization of the ligament. The evaluation of the toughness under plane stress conditions was carried out by this method. This method has been extensively performed in order to assess the performance of two parameters in fracture, i.e., essential work of fracture and nonessential work (βwp) ones.

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