Browsing by Author "Bouali, E."
Now showing 1 - 10 of 10
- Results Per Page
- Sort Options
Item Analysis of crack evaluation standards in welded joints of pipelines(Elsevier, 2005) Bouzid, R.; Bouali, E.; Gaceb, M.Item Approche probabiliste au contrôle et suivi des joints de soudure des conduites(2007) Abdelbaki, Noureddine; Bouali, E.; Bouzid, R.; Gaceb, M.Les conduites de transport des hydrocarbures sont des constructions mécano-soudées, confrontées en exploitation à des conditions particulières de fonctionnement. Les ruptures des joints de soudure des conduites, bien que rares, ont des conséquences majeures aux niveaux humain, environnemental et économique. Ces derniers sont le siège de formation des fissures de fatigue. L'utilisation des résultats d'inspection in situ, à partir des techniques de contrôle non destructif, est une composante essentielle de la réévaluation et du maintien de l'intégrité des conduites dans leur fonction. Elle nécessite des méthodes de calcul et des outils d'aide à la décision en appui des campagnes d'inspection et de réparation. C'est dans ce contexte que la présente étude a été réalisée qui est une contribution à l'effort méthodologique d'évaluation de l'endommagement par détection de fissure et d'estimation de la durée de vie résiduelle des joints de soudure sous sollicitations en fatigueItem Establishment of data base and a classification of defects in the metal of pipes according to their severity(Elsevier, 2012) Bettayeb, M.; Bouali, E.; Abdelbaki, Noureddine; Gaceb, M.Given the distances between areas of production and consumption of hydrocarbons, transport by pipeline is the most competitive means. These pipelines made of metal pipes can contain several types of defects of different origins. These defects can lead to pipeline failures that may have serious consequences resulting in ecological or financial disasters. The causes of these failures can be of various kinds. To assess the integrity and study the ageing of hydrocarbons transport pipelines is a current problem in the world which must be solved. The degraded state of thousands of kilometers of pipeline in the world requires the elaboration of rehabilitation by repair or replacement programs of sections in poor condition. If on one hand rehabilitation operations do improve the safety of hydrocarbons transport pipelines and prolong their remaining life, they are very expensive on the other. Therefore they must be carried out according to a previously well established plan, which determines the priority given. This priority must be defined by a multi-criteria evaluation, which also includes the criterion of severity of the defects located in the pipes metal according to the result of previous inspections of the pipelines towards the importance and the integrity of each section of the pipe.In this context the elaboration of a database and a classification of the defects in the metal of the hydrocarbons transportation pipes according to their severity are essential in this studyItem Influence of properties of large pipes on the reliability of pipelines(2008) Abdelbaki, Noureddine; Bouali, E.; Gaceb, M.; Bouzid, R.Item Reliability of an unstable pipeline used for natural gas transportation(2007) Abdelbaki, Noureddine; Bouali, E.; Bouzid, R.; Gaceb, M.Item Semi-probabiliste approach of hydrocarbons canalization(2007) Abdelbaki, Noureddine; Bouali, E.; Bouzid, R.; Gaceb, M.Item Study of defect admissibility in gas pipelines based on fracture mechanics(School of Engineering, Taylor’s University College, 2009) Abdelbaki, Noureddine; Bouali, E.; Gaceb, M.; Bettayeb, M.Bearing in mind the considerable distances between natural gas fields and consumers’ appliances, transport by gas pipelines remains the most competitive means. These gas pipelines which are generally made of steel pipes may contain however several types of defects of various origins and which are susceptible to initiate cracks which may grow under some circumstances to such extent as to lead to fracture. Failures of gas pipelines may have serious consequences and may lead to catastrophes from ecological and financial viewpoints. It is therefore interesting to study the defect admissibility so as to maximize safety and minimize exploitation costs through a simplified method based on the Failure Assessment Diagram (FAD). The latter is used in conjunction with Finite Element Analysis (FEM) applied to fracture mechanics to help decision making as to whether a given defect present in a pipe is acceptable or notItem Study of life and mechanical properties of welded joints of big diameter pipelines(2005) Abdelbaki, Noureddine; Fenineche, N.; Bouali, E.; Bouzid, R.; Gaceb, M.The increase in transportation capacities of pipe-lines necessitates the introduction of new construction tubes and new production technologies. Tubes should be produced according to pipe-lines service parameters. It is therefore useful to produce tubes which vary in diameter, in construction and mainly in the type of steel used for their production. For pipe of great diameter, destined to support high pressure, we use welded tubes made of controlled rolled steel and low alloyed improved steel. Tubes are the main constituents of pipe-lines. Their quality, the properties of their material and their welded joints determine to a high degree the possible deficiencies, stoppages and failures of pipe-lines. This is the reason why it is important to determine the requirements on tube steel and welded joints in terms of the service parameters of pipe-lines in order to avoid their rupture. The welded joints of tubes are subjected to complex static and dynamic loading, which takes place during pipe transportation, and during realization and exploitation of pipelines. The welding process of big diameter pipes is characterized by a great volume of melted metal and a large heat affected zone of the parent metal. The temperature in the vicinity of the weld joints varies from the melting temperature at the joint to lower temperatures in adjacent zones. In the region of the parent metal subjected to this temperature variation important alterations in the structure and in properties of the material take place. This is why it is estimated important to study this zone in which there is a reduction in the plasticity and the resilience of the metal and consequently there will be an increase in the probability of crack formation. The creation of a mechanical non-homogeneity in this zone reduces the work capacity of the weld joints and the reliability of pipe-lines reduces. It is in this context that the paper presented includes two parts: The first part is concerned with the hardness distribution and the resilience variation as a function of the temperature distribution in the heat affected zone of pipe. The second part considers the influence of the weld joint shape and the loading regime of the pipe-lines on their weld joints life in the big diameter pipes. This work shows how the bearing capacity of the weld joints wary with the mechanical non-homogeneity of weld properties and quality with their weld shape and with the relative thickness of the diameter layer in the welding. On the other hand this study shows the resilience variations in weld joints and in the parent metal of the pipes in the as bought state and after their mechanical ageing. The stress and strain concentration resulting from irrational configuration of welded joints cause the strength of weld subjected to cyclic loading to be diminished. This has lead to finish this work by the determination of the life specimens taken from weld joints in tubes and subjected to cyclic loads during testingItem Welded Joints in canalisations subjected to dynamic loads(Ed. Elsevier, 2005) Gaceb, M.; Bouali, E.; Bouzid, R.