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.
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.
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.
A paper published in » Engineering Failure Analysis » finded on ScienceDirect.com.
The analysis of an abnormal failure of forklift forks is presented in this work. The investigation results suggested that failure occurred due to fatigue mechanism followed by sudden overload fracture. The orientation of fatigue fracture indicates abnormal lifting operation, favouring crack initiation from outer fork area which is the compression designed zone. Moreover, various surface flaws and weakness areas (such as surface marks, decarburized microstructures and weld zones) identified on the outer fork zone, compromise fatigue strength inducing premature crack nucleation and fast growth towards final failure.
Read the article : click here
This paper presents a detailed analysis of a nose landing gear failure. The developed work comes following an accident occurred in which the nose of the landing gear’s fork of a light aircraft bent during landing. Nose gear failures are a high concern in the aviation industry. According to Federal Aviation Administration, in average 55% of aircraft failures occur during takeoff and landing while the remaining occurs during flight
A paper published in « Case Studies in Engineering Failure Analysis« , available on sciencedirect.com.
As a qualification of bolt for flight assembly, the bolt assembly has undergone proof pressure test at 2.4 MPa, Vibration test at frequency range of 20–100 Hz, ±3 db/oct for 120 s in both lateral and longitudinal directions and flight acceptance test. During routine visual inspection before electrical check, it was observed in one of the three fasteners that the head of the bolt had got sheared off from the shank portion of bolt. Further, a failure analysis was carried out on the failed bolt.
The objective of the study is metallurgical analysis of the failed bolt, fractography study to find out the root cause of the failure, and optimization of processing parameters for fastener manufacturing.
An article in progress in « Case Studies in Engineering Failure Analysis », Volume 7 (october 2016).
This paper presents the results of a failure analysis investigation conducted in a connecting rod from a diesel engine (18 V, four-stroke) used in the generation of electrical energy. The continuous output of the engine was 10.5 MW, at 600 rpm ; before the failure of the con-rod it accumulated 35836 service hours, working with a load factor of 80%.
L’étude expérimentale confiée par EDF au Cetim a eu pour objectif de déterminer l’influence du mode de chargement sur la vitesse de propagation en fatigue de fissures transverses circonférentielles et d’évaluer les éventuels effets d’échelle.
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.
A Ghent University Academic Bibliography publication.
Offshore constructions are subjected to cyclic loading conditions. This situation is combined with the corrosive nature of the surrounding environment. This literature review first introduces the reader to corrosion fatigue. Thereafter a critical comparison of some typical lab-scale fatigue corrosion test setups is given. Special emphasis is devoted to the instrumentation of the setup. This is followed by a design criteria summary which will be used to design a new corrosion fatigue test set-up for evaluating the fatigue properties of steel components in sea water environnent. Read more
Une équipe d’EDF Recherche et Développement a confié au Cetim un programme de recherche expérimentale visant à améliorer les connaissances d’EDF R&D dans le domaine de la propagation de fissures sous chargements multiaxiaux.
L’étude expérimentale confiée au Cetim a eu pour objectif de déterminer l’influence du mode de chargement sur la vitesse de propagation en fatigue de fissures transverses circonférentielles et d’évaluer les éventuels effets d’échelle.
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.
