Deux conduites forcées sur écoute

EDF-Tignes-Malgovert_Img_DetailReference

 

EDF a mis sous surveillance par émission acoustique les conduites forcées de la centrale de Malgovert. Objectif : détecter en temps réel, pendant deux années et demie, la rupture de frettes en acier à haute limite élastique.

 

Pour cela, Le Cetim a développé en 2011 un système basé sur le principe de l’émission acoustique. Des tests de propagation d’ondes ont d’abord été menés sur site afin de rechercher les capteurs les mieux adaptés tout en optimisant leur nombre. La simulation des ruptures de frettes sur site a ensuite permis de s’assurer de l’efficacité des capteurs à moyenne fréquence (100 kHz) pour détecter les défauts. Le bruit de fond dû à la circulation de l’eau dans les conduites a également été analysé.

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Publicités

Primary hip replacement stem taper fracture due to corrosion in 3 patients – Acta Orthopaedica –

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A interesting article published online: 11 Jan 2016, in « Acta Orthopaedica « .

Wear and corrosion of taper connections in modular hip prostheses have gained much attention due to the serious biological response that can occur due to the metallic debris originating from this articulation.They present 3 cases of stem taper fracture as the ultimate failure mode of this design.

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La qualité des prototypes n’attend pas

Delphi-Automotive_Img_DetailReferenceTrier en un temps très court un lot de 5 000 pièces en fonction de leur teneur en austénite résiduelle : c’est le défi que l’entreprise Delphi Automotive a réalisé en utilisant la méthode des courants de Foucault basse fréquence.

 

Le Cetim a étalonné les équipements, défini les critères d’analyse et un mode opératoire simple. En deux jours, deux opérateurs de Delphi ont passé aux cribles les 5 000 pièces prototypes. En fonction du taux d’austénite résiduelle affiché à l’écran, les pièces ont été considérées comme bonnes ou non. Fort de ces résultats, Delphi envisage aujourd’hui d’automatiser ce contrôle instantané pour l’installer sur les sites qui produiront ces pièces.

Pour en savoir plus, lire le document.

Contrôle des sphères par émission acoustique

CHAUDRONNERIE

Le Cetim est intervenu à la demande du Centre technique des industries mécaniques et électriques de Tunisie (Cetime). Objectif : mettre en place les contrôles de quatre sphères de stockage de GPL de la SNDP Agil.

Pour en savoir plus, lire le document.

 

 

Les compétences du Cetim s’expriment à travers sa capacité à maîtriser l’ensemble des technologies mécaniques. Les cas qui sont présentées ici exposent des exemples de réalisations menées pour ses clients tant à titre collectif qu’à titre individuel. Elles témoignent de la capacité du Cetim à proposer une offre globale et personnalisée de prestations autant pour les grands donneurs d’ordre que pour les petites entreprises.

 

Needle Roller Bearing at Gudgeon Pin of Ginning Machine

A2016-01-14_09h23_47 paper published by IJRET (International Journal of Research in Engineering and Technology).

In ginning machine where space is limited for driving the mechanism a Needle roller bearing having diameter of 20 mm is used in between connecting rod and head pin to give the relative motion between parts. As the continuous impacting of repetitive load on bearing, it fails with in shorter period of time if proper lubricant is not supplied by grease gun after 2 to 3 hours. While bearing are considered under observation it is found that bearing are fail due to brinnelling. So design and analysis of needle roller bearing is vital to calculate the life of bearing and to make sure whether this bearing is suitable or not. So it becomes mandatory in designing to calculate radial load applied on bearing as the bearing is rolling contact bearing, from this life of the bearing can be calculated and finally analysis by ANSYS software is done to find the result so that we can conclude for bearing.

Read more at : IJRET20150411007.pdf

Case Study of severe Strip Breakage in Rolling Mill of TSCR

Microsoft Word - Breakage_final_v4.docxA new case study of Failure Analysis published in « Case Studies in Engineering Failure Analysis » of December 2015.

In this paper, a case of severe strip breakage in rolling mill of Thin Slab Casting and Rolling (TSCR) shop of TATA Steel, Jamshedpur is presented.Visual observation revealed complete splitting with material missing along the central axis of the strip. Presence of defects in form of white stringers, white patches and holes were observed along the same axis just ahead of split location. Metallurgical analysis revealed association of these defects with slag type foreign materials in the rolled strip. The entrapments of un-deformable materials like slag in slab resulted in the formation of surface discontinuities on the strip on account of differential rolling. The discontinuities manifested in form of holes at lower strip thickness in the later stands of the mill. Inhomogeneous deformation about such holes also resulted in material overlapping. In summary, the breakage of the strip was found to have a strong correlation with the presence of heavy chunk of foreign inclusions from secondary steelmaking sources.

Read more : Case Study of severe Strip Breakage in Rolling Mill

Effect of Water Hammer on Bent Pipes in the Presence of a Pre-crack

978-3-319-17527-0Un autre article paru dans la revue « Design and Modeling of Mechanical Systems de mars 2015.

In this study, transient pressure in piped liquid due to waterhammer is a function of structural restraint at elbows. To study the effect of this phenomenon on polyethylene elbowed pipe networks, experimental tests were performed on polyethylene bent pipes, either in the absence or presence of a pre-crack by measuring the toughness and determining the mechanical behavior of HDPE. These characteristics were been used to perform simulations using ABAQUS software, the internal pressure increase, to investigate the safety of bent pipes using an angle of 90 ° bend with 11.4 mm thickness and a right portion of 150 mm as length

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Failure Analysis of HDPE Pipe for Drinking Water Distribution and Transmission

Un article paru dans la revue « Design and Modeling of Mechanical Systems » de mars 2015.

« Pipes and elbows are important components in any piping systems for transportation of water. These structures are subjected to complex loads taking into account their geometrical configuration and the multiplicity of the loading conditions in service. The origin of failure of these mechanical components is directly related to the presence of defects. The principal objective of this work is to analyze the severity of defects on high density poly-ethylene pipe widely used for water piping networks. »

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Shape Fastener of the Bus Skeleton Testing

fasternerA paper presented at « International Conference on Electromechanical Control Technology and Transportation » (ICECTT 2015).

The paper deals with the bending tests of new designed joints for bus skeletons. The frames of buses have to satisfy various demands, but the safety of the passengers is the priority. The actual welded joints should be replaced by new type of profiles connections in the future. Finite elements method was used for the bending test simulation and for the stress investigation; the real experiments were done using the universal test equipment ZD10/90. Obtained results are comparable, so authors aim to realize next experiments in next days at which other shapes of the joints will be tested. Read more

Failure Analysis: Case Study Challenger SRB Field Joint

challenger85An article which will be published in International Journal of Engineering and Technology, Vol. 8, No. 6, December 2016.

The Challenger Solid Rocket Boosters (SRB) Field Joint initial design was deemed as a direct cause of the shuttles catastrophic failure during lift off.  The Field Joint SRB was a key component in containing dangerous gases produced in the SRB.  After conducting research on the Challenger accident, a Fault Tree Analysis was developed to analyze the reliability of the SRB field joint configuration in relation to its goals.  The reliability model will show how the field joint fell short in terms of operational reliability.   Read more at.