Archives de l’auteur : geraldb17

Haro sur la rouille en pleine mer !

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Les projets sont nombreux pour surveiller et protéger les infrastructures Offshore. La 26e édition d’Eurocorr, le congrès annuel de la Fédération européenne de la corrosion, en septembre 2016 à Montpellier, est revenue sur plusieurs d’entre eux, à retrouver dans une note de veille du Cetim intitulée : « Eurocorr 2016 – Protection cathodique, corrosion marine ». On y apprend que les moyens utilisés pour lutter contre la rouille sont parfois high-tech. C’est ainsi, avec l’aide d’un sous-marin téléopéré que Total SA en France et South Offshore au Congo posent, à plus de 40 mètres de profondeur, des anodes sacrificielles pour renforcer la protection cathodique de plateformes marines vieilles de plus de 30 ans.

Retrouvez l’intégralité de la note de veille de février 2017 « Eurocorr 2016 – Protection cathodique, corrosion marine », sur le site du Cetim, rubrique « Mécathèque ».

Failure Analysis of Internal Combustion Engine Valves: A Review

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An article published in « International Journal of Innovative Research in Science, Engineering and Technology« , december 2012.

Those study focuses on different failure modes of internal combustion engine valves, failures due to fatigue at high temperature, high temperature effects on mechanical properties of materials, like hardness and yield strength; wear failure which is due to impact loading, and wear rate that depends on load and time. For the study of fatigue life, a combined S-N (max. stress v/s number of cycles) curve is prepared. Such a curve helps in comparing the fatigue failure for different materials at different high temperatures and may also assist the researchers in developing the valve materials with a prolonged life.

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Spark Plug Failure

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1-s2-0-s2213290213000072-gr2An interesting paper in « Case studies in Engineering Failure Analysis » published on ScienceDirect.com.

This paper studies the failure of spark plugs designed for optimal durability which failed after only 100 hrs of operation. SEM-observation showed that in failed plugs the insulator was covered with a deposit consisting of iron oxides and soot.

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Low hardness on bearing race

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

Presence of decarburization on rolled bar coupled with out of square forging can lead to the presence of decarburized layer on one of the faces of a bearing race. This decarburized layer gives rise to low hardness on the face of the race. A series of examinations including micro-structural and macroscopic examinations on the defective samples revealed out of square forging as a root cause for the presence of the decarburized layer on a part of the one of the faces of a bearing outer race. This paper brings out the detail of investigation carried out.

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Fractography of a neck failure in a double-modular hip implant

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2017-02-23_09h32_35An article published in « Case Studies in Engineering Failure Analysis« , 2014.

The tapered joints of modular hip implants are prone to fretting and crevice-corrosion. This can lead to total failure in under a year, especially for heavier, more active implant recipients. In this study, fractography of a failed Profemur Z implant showed that a life limiting fatigue crack was nucleated on the anterolateral surface of the implant’s neck. The fatigue crack nucleation area appeared to have both more fretting damage and a higher corrosion rate than on other surfaces of the neck.

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Analysis of internal corrosion in subsea oil pipeline

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

Failure of a subsea crude oil API 5L X52 steel pipeline which led to oil leakage has been reported to occur after 27 years in service. Some leaks were found to form at the bottom of the horizontal API 5L X52 steel pipeline near an elbow section which connected the pipeline to a riser.

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Issues to improve the safety of 18K370 steam turbine operation

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2017-02-23_09h04_00An article published by « E3S Web of Conferences 13, 04003 (2017)« .

The paper presents the process of improving the safety and reliability of operation the 18K370 steam turbines Opole Power Plant since the first failure in 2010, up to install the on-line monitoring system. It shows how the units work and how to analyse the contol stage as a critical node in designing the turbine. They have also briefly discussed the way of lifecycle management of individual elements. The presented actions could be considered satisfactory, and improve the safety of operating steam turbines of type 18K370.

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Evaluating the coupled thermo-mechanical stresses for an aluminum alloy piston used in a gasoline engine

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2017-02-02_09h44_08An article published in « The Journal of Engine Research » Vol. 42 (Spring 2016).

In the modern engines with higher compression ratios, severe pressures and
non-uniform heating up is occurred for the engine parts. The piston as the
most critical part among all automotive components has been the subject of
numerous studies on calculation of temperature distribution, but thermal
stress analyses are limited. In this study, the piston of gasoline engine XU7
which is widespread in Iran transport section is considered for thermomechanical
investigation.

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Failure analysis of a nose landing gear fork

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2017-02-02_09h26_14This 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

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Engrenages : les vertus du grenaillage

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2017-01-19_09h32_56Comment améliorer la résistance à la fatigue des engrenages ? Ce nouvel ouvrage de la collection Performances du Cetim explore les réponses proposées dans la littérature et les soumet à l’épreuve des faits ! Des études ont d’ores et déjà montré que le grenaillage appliqué aux engrenages influence de façon notable le comportement en fatigue de flexion. Mais qu’en est-il pour la fatigue de contact ? L’ouvrage, intitulé « Influence du grenaillage sur la tenue en fatigue de contact » (9Q178) répond à cette question.

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