Failures of cranes due to wind induced vibrations

An interesting paper in « Engineering Failure Analysis »published on ScienceDirect.com.

Two different crane types suffered severe wind induced vibrations of tension bars for the counter weights during standstill periods. The vibrations led to fatigue fractures of tensions bars followed by collapses of the cranes. The parameters of wind speed and angle for the tension bar profiles were identified conducting comparative wind tunnel experiments. Recommendations for identification and prevention of wind induced galloping vibrations of tension bars were developed.

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Cas Concrets : ruptures brutales ou par fatigue d’arbres

Avatar Cas ConcretsArbres de transmission de couples ou axes de rotation, voici trois cas concrets d’analyse de ruptures d’arbres ayant des origines différentes : problème de matière, d’usinage, de sollicitations anormales.

Retrouvez dans la Mécatech les ré-éditions des fiches d’analyse de cas concrets que le Cetim a publié dans la revue Cetim-Informations dans les années 1974 à 1990. Bien qu’anciennes, le contenu de ces fiches est toujours d’actualité.

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L’analyse de défaillance est affaire de méthode

L’analyse des défaillances d’organes de machines ou d’équipements s’appuie sur un cheminement logique, il est important de le suivre car il permet d’exploiter au mieux les indices que ne manquent pas de recéler les pièces ou ensembles détériorés. Depuis 50 ans le Cetim analyse et propose des solutions pour de très nombreux cas de défaillance d’organe de machines.

Lire l’article : cliquez ici

Cracking on joint lug of aluminum alloy framework of an airplane

A new interesting paper in  » Engineering Failure Analysis » published on ScienceDirect.com.

An aluminum alloy joint lug of the framework of an airplane was found to have a crack near the bolt hole after serving for a period. The failure mode is stress corrosion cracking.  The cracking of the inner surface anodic oxidation film is the main cause. Some prevention measures for such failure were proposed.

This paper brings out the detail of investigation carried out.

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Crankshaft failure analysis

A new interesting paper in  » Engineering Failure Analysis » published on ScienceDirect.com.

A case study of a crankshaft catastrophic failure of a motor vehicle and its failure analysis is presented. The crankshaft suffered a mechanical seizure on the crankpin no. 2 after 3 years in service. It was repaired and after 30,000 km the vehicle had a damage again, with a catastrophic failure on the same crankpin.

More at : Crankshaft failure analysis of a motor vehicle.

Analysis of a corrosion under insulation in refinery line

A case study published on october 2013 in « Case Studies in Engineering Failure Analysis« .

An explosion and fire occurred at a refinery site leading to the evacuation of the site and to millions of pounds worth of damage to the facility. A laboratory investigation was carried out to establish the immediate cause and any underlying factors that may have contributed to the incident.

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Failure investigation of a Taper Roller Bearing: A case study

Premature failure of a taper roller bearing was investigated to arrive at the root cause. The investigation included visual examination, chemical analysis, optical metallography, hardness and estimation of retained austenite. The metallurgical properties were as per the specification. The reason for premature failure was traced to misalignment that led to uneven load distribution of the rollers and the raceway. The failure mechanism illustrated was in agreement with the test results and also in concurrence with the earlier theoretical studies found in literature.

via : ScienceDirect.com – Case Studies in Engineering Failure Analysis – Failure investigation of a Taper Roller Bearing: A case study.

A failure study of the railway rail serviced for heavy cargo trains

An interesting paper published in Case Studies in Engineering Failure Analysis, Volume 1, Issue 4, October 2013.1-s2.0-S2213290213000461-gr2

In this case study, a failed railway rail which was used for heavy cargo trains was investigated in order to find out its root cause. The crack is supposed to be initiated from the weaker ferrite networks. Given all of that, the failed railway rail is considered to be caused by overload. It is of great importance to improve the welding technology, and control the load of train in order to prevent similar failure in future.

Source : A failure study of the railway rail serviced for heavy cargo trains

Handling abuse causes premature bearing failures

An article published in « Case Studies in Engineering Failure Analysis » .

A bearing, can fail prematurely due to a variety of factors like wrong choice of a design for the application, lack of or inadequate lubrication, impact loads, vibrations, environmental factors like operating temperature, corrosive media, moisture, dirt or handling abuse during transport, mounting, reinstallation and servicing.

Two case studies are presented here wherein abusive handling likely caused premature fatigue failure of ball bearings.

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Défaillances par corrosion : jeudi 28 septembre 2017 au Cetim Nantes

Mis en avant

Journée Technique

Des outils pour prévenir et guérir

La corrosion reste un redoutable ennemi industriel, et ce, en dépit des avancées scientifiques et des progrès technologiques de ces dernières décennies. Elle est encore aujourd’hui responsable d’un grand nombre d’avaries et touche de nombreux domaines.

Ses causes sont multiples et sa maîtrise fait appel à des compétences variées.Elle revêt différentes formes et un cas apparemment simple peut cacher un phénomène complexe. Sa détection et sa mesure sont souvent une affaire de spécialistes.

Ayez les bons réflexes et venez profiter de notre expertise à l’occasion de cette journée, qui vous aidera à prévenir et guérir ce mal industriel.

Participation gratuite – Inscription obligatoire et limitée à deux personnes par établissement

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