Publications Internationales

Permanent URI for this collectionhttps://dspace.univ-boumerdes.dz/handle/123456789/13

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Author: search.filters.author.Benammar, Samir

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Now showing 1 - 10 of 10
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    A contribution to structural reliability analysis of composite high-pressure hydrogen storage tanks
    (KONBiN, 2023) Sid Amer, Youcef; Benammar, Samir; Fah tee, Kong; Wadi, Mohammed; S. Jouda, Mohammed
    Although composite high-pressure tanks are a subject of growing interest, especially for hydrogen storage applications, a detailed structural reliability analysis still needs to be improved. This work aims to provide a probabilistic investigation of the mechanical response of composite high-pressure hydrogen storage tanks using the Monte Carlo Simulation method. A performance function based on the circumferential model of composite pressure cylinders is employed with five random design variables. According to the results, the internal pressure and the helical layer thickness are the foremost parameters significantly impacting the structural reliability of the tank, whereas, the helical layer thickness and winding angles have a minor influence. In addition, high coefficients of variation values cause the contraction of the safety margin potentially leading to the failure of the composite hydrogen high-pressure tank. The obtained results were validated with experimental tests available in the literature.
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    Failure Probability Analysis of Composite Pressure Tanks Using Subset Simulation
    (Semnan University, Faculty of Mechanical Engineering, 2024) Sid Amer, Youcef; Benammar, Samir; Tee, Kong Fah; Iourzikene, Zouhir
    Composite pressure tanks have received increased attention across a number of civilian applications due to their lightweight and high strength. Traditionally, the design of composite vessels is based on deterministic analysis. However, the design of these structures is challenging and involves several kinds of uncertainties. In fact, different computational investigations have been carried out but no studies provide a resolution for small failure probability evaluation of composite pressure tanks. The aim of this study is to establish a computational framework to investigate small failure probability levels of composite tanks using the Subset Simulation method (SS). The model was developed in two steps, first, the development of limit state functions for hoop and helical layers using netting analysis, and afterwards, a probabilistic computation with six random variables. To quantify the effect of the randomness of different parameters on the structural reliability of composite tanks, a sensitivity analysis was performed using different values of coefficients of variation (COV). It was observed from the results that SS has the ability and the accuracy required to evaluate small failure probabilities which are commonly encountered in composite tank applications. In addition, the hoop strength, the internal pressure, and the thickness of the composite are the major design variables that have a great impact on the structural reliability of the axially symmetric composite tank whereas the fiber winding angle has little effect. Moreover, high COV values drastically reduce the safety zone, which could eventually lead to the burst failure of the composite pressure tank. Furthermore, this study implements a reliability-based design from the perspective of hoop and helical composite layer thicknesses, thus providing a rational assessment of the risk of structural failure.
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    Dynamic failure analysis and lifetime estimation of Tool-string in rotary drilling system under Torsional-Axial coupled vibrations
    (Elsevier, 2022) Kessai, Idir; Benammar, Samir; Doghmane, M.Z.
    Failure analysis and lifetime assessment of drilling systems are very important to reduce maintenance costs. Of all the failure modes, coupled vibration due to the stick–slip phenomenon is the most common problem that can affect rotary drilling systems. The main objective of this study is to estimate the number of cycles before failure (useful life) of the lower part of rotary drilling system toolstring under axial and torsional vibrations. To achieve this goal, a complete procedure based on different methods and approaches, such as: finite element method (FEM), rainflow counting method (RFM), Goodman approach (GA), S-N diagram and Miner’s rule, has been proposed. To this end, the FEM has been used to determine the loading cycles (equivalent stress); whereas, the number of stress cycles in the loading cycle diagram has been counted using RFM. The GA has been used to select the main cycles that can cause failure on the toolstring and to calculate their amplitudes. Then, S-N diagram has been used to determine the number of cycles to failure of the toolstring. Finally, Miner’s rule has been applied to find the approximate time to failure of the drilling system. Regarding the estimation of the toolstring lifetime, the results obtained have shown a good agreement with real data recorded in an oil field in Algeria
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    Criticality analysis and maintenance of solar tower power plants by integrating the artificial intelligence approach
    (MDPI, 2021) Benammar, Samir; Tee, Kong Fah
    Maintenance of solar tower power plants (STPP) is very important to ensure production continuity. However, random and non-optimal maintenance can increase the intervention cost. In this paper, a new procedure, based on the criticality analysis, was proposed to improve the maintenance of the STPP. This procedure is the combination of three methods, which are failure mode effects and criticality analysis (FMECA), Bayesian network and artificial intelligence. The FMECA is used to estimate the criticality index of the different elements of STPP. Moreover, corrections and improvements were introduced on the criticality index values based on the expert advice method. The modeling and the simulation of the FMECA estimations incorporating the expert advice method corrections were performed using the Bayesian network. The artificial neural network is used to predicate the criticality index of the STPP exploiting the database obtained from the Bayesian network simulations. The results showed a good agreement comparing predicted and actual criticality index values. In order to reduce the criticality index value of the critical elements of STPP, some maintenance recommendations were suggested
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    Rock–bit interaction effects on high-frequency stick-slip vibration severity in rotary drilling systems
    (Emerald, 2021) Mendil, Chafiaa; Kidouche, Madjid; Doghmane, Mohamed Zinelabidine; Benammar, Samir; Tee, Kong Fah
    Purpose: The drill string vibrations can create harmful effects on drilling performance because they generate the stick-slip phenomenon which reduces the quality of drilling and decreases the penetration rate and may affect the robustness of the designed controller. For this reason, it is necessary to carefully test the different rock-bit contact models and analyze their influences on system stability in order to mitigate the vibrations. The purpose of this paper is to investigate the effects of rock-bit interaction on high-frequency stick-slip vibration severity in rotary drilling systems. Design/methodology/approach: The main objective of this study is an overview of the influence of the rock-bit interaction models on the bit dynamics. A total of three models have been considered, and the drilling parameters have been varied in order to study the reliability of the models. Moreover, a comparison between these models has allowed the determination of the most reliable function for stick-slip phenomenon. Findings: The torsional model with three degrees of freedom has been considered in order to highlight the effectiveness of the comparative study. Based on the obtained results, it has been concluded that the rock-bit interaction model has big influences on the response of the rotary drilling system. Therefore, it is recommended to consider the results of this study in order to design and implement a robust control system to mitigate harmful vibrations; the practical implementation of this model can be advantageous in designing a smart rotary drilling system. Originality/value: Many rock-bit functions have been proposed in the literature, but no study has been dedicated to compare them; this is the main contribution of this study. Moreover, a case study of harmonic torsional vibrations analysis has been carried out in well-A, which is located in an Algerian hydrocarbons field, the indices of vibrations detection are given with their preventions
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    Failure probability analysis of heliostat systems
    (Inderscience, 2020) Benammar, Samir; Tee, Kong Fah
    Heliostats represent the most important maintenance cost in the solar power tower plant. The aim of this work is to provide a failure probability analysis for heliostat design in order to minimize this maintenance cost. Based on mechanics of material study and wind aerodynamic analysis, a performance function, with five random variables, has been developed wherein the random variables are: wind speed, inside and outside pedestal diameters, pedestal yield stress and mirror mass. Four main methods have been proposed: first order reliability method, second order reliability method, Monte Carlo (MC) method and subset simulation (SS) method. The variation of failure probability with the variation of pedestal wall thickness and wind speed, for different outside diameters and heliostat azimuth and elevation angles, has been simulated. The results show that SS is more efficient and accurate for small failure probabilities; however, MC is more accurate for high failure probabilities
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    Drill Bit Deformations in Rotary Drilling Systems under Large-Amplitude Stick-Slip Vibrations
    (MDPI, 2020) Kessai, Idir; Benammar, Samir
    In oil and gas industry, rotary drilling systems are used for energy exploration and productions. These types of systems are composed of two main parts: mechanical and electrical parts. The electrical part is represented by rotating motor called top drive; however, the mechanical part of the system is composed of tool string with many pipes, at the bottom end of these pipes the bit is attached to cut the rock during their contact. Since the bit is in a direct contact with rock characteristic variations, it can be under risk for heavy damage. The latter is principally caused by the fact that the rock–bit interaction term is highly nonlinear and unpredictable. In literature, many mathematical models have been proposed for rock–bit interaction, but they do not reflect the dynamic of the bit under vibrations since torsional and axial vibrations are strongly coupled and synchronized with it. In industrial development, the design of drill bit has faced many improvements in order to overcome these vibrations and mitigate unpredictable phenomena. Even though, the practical use of these drill bits confirmed that there are still many failures and damages for the new designs; moreover, bits’ virtual life become shorter than before. The objective of this study is to analyze the drill bit deformations caused by the stick-slip vibration phenomenon which is characterized by high-frequency high-amplitude in rotary drilling systems. The obtained results were validated through a case study of MWD (measurement while drilling) data of well located in a Southern Algerian oil field
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    Contribution to the modeling and simulation of solar power tower plants using energy analysis
    (Elsevier, 2014) Benammar, Samir; Khellaf, A.; Mohammedi, K.
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    Fault detection and isolation based on neural networks case study : steam turbine
    (2011) Benazzouz, D.; Benammar, Samir; Adjerid, Smail
    The real-time fault diagnosis system is very important for steam turbine generator set due serious fault re-sults in a reduced amount of electricity supply in power plant. A novel real-time fault diagnosis system is proposed by using Levenberg-Marquardt algorithm related to tuning parameters of Artificial Neural Network (ANN). The model of novel fault diagnosis system by using ANN are built and analyzed. Cases of the diag-nosis are simulated. The results show that the real-time fault diagnosis system is of high accuracy and quick convergence. It is also found that this model is feasible in real-time fault diagnosis. The steam turbine is used as a power generator by SONELGAZ, an Algerian company located at Cap Djinet town in Boumerdes dis-trict. We used this turbine as our main target for the purpose of this analysis. After deep investigation, while keeping our focus on the most sensitive parts within the turbine, the weakest and the strongest points of the system were identified. Those are the points mostly adequate for failure simulations and at which the de-signed system will be better positioned for irregularities detection during the production process