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.

Failure analysis of piano strings

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

This paper studies the failure cause of two types of piano strings. Were taken into consideration bass and acute strings of a grand piano concert broken up. The mechanisms leading to rupture the strings are examined. The critical points studied are : tuning pin, agraffe, compression points, environment, tuner.

Read more at : Failure analysis of piano strings.

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.touche Read more

Failure of rubber O-ring

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

This paper presents the effects of hydrogen pressure, ambient temperature and pressure cycle pattern on fracture behavior of O-rings moulded from a peroxide-crosslinked EPDM rubber with white reinforcing filler under cyclic exposure to high-pressure hydrogen gas.

Read more at : Failure behavior of rubber O-ring under cyclic exposure to high-pressure hydrogen gas

 

NDT in fiber reinforced composites with the pulsed ultrasonic polar scan

A new paper in « Polymer Testing« .

This study investigates the use of both amplitude and time-of-flight based pulsed ultrasonic polar scan P-UPS as a sophisticated non-destructive damage sensor for fiber reinforced composites. Focus is put on stiffness related damage phenomena, which are in general difficult to monitor nondestructively, and their associated signature in the P-UPS image. This paper brings out the study, read more via Non Destructive damage assesment in fiber reinforced composites with the pulsed ultrasonic polar scan.

2013 un bilan de l’activité du blog Les Experts Analyse Défaillances

Les lutins statisticiens de WordPress.com ont préparé le rapport annuel 2013 de ce blog.

En voici un extrait :

Le Concert Hall de l’Opéra de Sydney peut contenir 2.700 personnes. Ce blog a été vu 12  000 fois en 2013. S’il était un concert à l’Opéra de Sydney, il faudrait environ 4 spectacles pour accueillir tout le monde.

Cliquez ici pour voir le rapport complet.

Failure of a Motor Vessel’s Crankshaft 1968

An interesting paper published in  « Engineering Failure Analysis » :

In July 1968 the Swedish motor vessel “MV Stureholm” traveled from Sweden across the North Atlantic with destination to the American gulf harbours.  About 100 nautical miles north of the peninsula Yucatan the 9,000 HP diesel engine failed as a consequence of fatigue failure of the crankshaft. The ship was disabled and had to be towed to Veracruz, Mexico. The Swedish shipowning company decided to perform a temporary repair in Veracruz by welding the fatigue crack. Back in Sweden the damaged but repaired crankshaft was dismounted from the engine and inspected by surveyors. The result was that a fatigue crack had initiated from a subsurface solidification (hot) crack.

This paper brings out the detail of investigation carried out. Read more at : Failure of a Motor Vessel’s Crankshaft 1968.

Premature cracking of dies for aluminum alloy die casting

Die casting AluminiumAn interesting paper of Bogdan Pawlowski, AGH University of Science and Technologie in Krakow, published in « Archives of Metallurgy and Materials » :

Two identical dies for aluminum alloy die-casting failed prematurely because of a number of parallel cracks on the working surface. These cracks were of a mechanical nature related to incorrect microstructural banding orientation of the die core and related to improper heat treatment. The root cause of premature cracking of dies was improper heat treatment (temper embrittlement).

More at :  http://imim.pl/files/archiwum/Vol4_2013/40.pdf

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 plus de 40 ans le Cetim analyse et propose des solutions pour de très nombreux cas de défaillance d’organe de machines.

Lire l’article : cliquez ici

Corrosion atmosphérique. Protection anticorrosion des équipements

Un ouvrage publié par le Cetim qui fait le point sur le sujet.

La corrosion est définie comme l’intéraction physico-chimique entre un métal et son milieu environnant. Elle entraîne la dégradation des propriétés fonctionnelles de l’équipement. Cette interaction est généralement de nature électrochimique.Les mesures de la corrosivité d’une atmosphère sont réalisées soit par mesure des polluants, soit par mesure de la vitesse de corrosion par exposition sur site de coupons de corrosion.Cet ouvrage fait le point sur les quatre classifications des corrosivités d’atmosphères répertoriées dans des normes de protection anticorrosion, ainsi que leurs formes qui varient selon le support métallique sur lesquelles elles s’appliquent : aciers, aciers inoxydables, alliages, aluminium, tôles, cuivres, etc. Plus d’info : cliquez ici

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