Case study: Analysis of the response of an aircraft structure caused by a propeller blade loss

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

One of the most severe failures in an aircraft provided with turboprops is an airscrew blade loss, this article is focused on the response of the structure after the break of a blade. The effects of stiffness and strength changes on the mounting system are analyzed. The research covers different parameters which can influence the phenomenon. The FEM model is suitable to simulate blade loss collapse sequence. The model has a perfectly-plastic material law and detects damage zones and failures…..Read more

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Failure of the Chassis of Roller Skates for Figure Skating

An interesting  paper in « Case study in Engineering Failure Analysis » published on ScienceDirect.com. This paper dealt with the analysis of a novel chassis for figure roller skates, made of P-AlMgSi alloy, which experienced a premature failure. An integrated approach had to be used to overcome the several criticalities of the study. The research led to the individuation of the primary cause of failure, standing in bending fatigue, due to the high number of jumps (i.e.: fatigue cycles) being performed during figure skating training. A solution to the problem was suggested, which led to an improved and optimized project of the chassis with positive outcomes (from the technical and mechanical points of view) in its use.

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Analysis and Optimization of Rocker ARM

An article published in the «  International Journal of Engineering Science and Computing« , September 2017.

A rocker arm is a valve train component in internal combustion engines. As rocker arm is acted on by a camshaft lobe, it pushes and opens either the intake or exhaust valve. This allows fuel and air to be drawn into the combustion chamber during the intake stroke or exhaust gases to be expelled during the exhaust stroke. Rocker arms were first invented in the 19th century and have been changed a little in function since then. Improvements have been made, however, in both efficiencies of operation and construction materials. About Rocker arm of Tata Sumo, vista. They will make the exact design of rocker arm of Tata sumo …..Read more

Catalogue formations 2018 : relevez les défis de demain !

Le catalogue formations 2018 du Cetim est disponible. Une offre regroupant 350 formations métiers déclinée en filières, dont une dédiée à l’industrie du futur avec notamment ses nouvelles technologies de fabrication additive, de robotisation ou de contrôle non destructif.

En 2018, le Cetim revoit complètement son offre de formations. Son objectif : coller toujours plus à la réalité des entreprises et aux évolutions technologiques et normatives dans lesquelles le monde industriel est engagé. Ainsi, c’est dans un nouveau format décliné en filières que le catalogue Formations 2018 présente les 350 formations métiers, animées partout en France, permettant aux ingénieurs et techniciens d’approfondir leurs connaissances dans un domaine de la mécanique.

Accéder au catalogue 2018

On the crystallographic, stage I-like, character of fine granular area formation in internal fish-eye fatigue cracks

The crystallographic character of fine granular area (FGA) formation from internal particles in martensitic high strength steel has been revealed by an assessment of the plastic zone size at the FGA border. This plastic zone size corresponded to about 3 times the martensite lath width. Tests at different temperatures (20°C, 200°C and 400°C) revealed a decreasing FGA size with increasing temperature at constant applied stress amplitude. As a consequence, the critical stress intensity factor varied as the FGA decreased with temperature. In contrast, the critical plastic zone size remained constant and equal to the sizes of microstructural features. This represents a strong similarity between crystallographic, stage I-like, crack propagation and FGA formation in a vacuum. ….Read the article

RECOMMANDATIONS PEINTURE POUR ARMOIRES ELECTRIQUES

La corrosion des armoires électriques d’Alstom Power avait-elle pour origine un problème de peinture ou une raison exogène ? En faisant appel au Cetim, l’industriel a trouvé la réponse, renforcé ses forces d’investigation et fourni des recommandations…Lire l’article.

 

Fault tree analysis of failure cause of crushing plant and mixing bed hall at Khoy cement factory in Iran

A paper published un « Case Studies ni Engineering Failure Analysis », april 2014.

Evaluating and analyzing the risk in the mining industry is a new approach for improving the machinery performance. We use fault tree analysis for modeling occurrence of undesired events (failures) in cement factory. In this model, The authors use fault tree analysis for modeling occurrence of undesired events (failures) in cement factory. They focused on crushing and mixing bed hall department. Analysis of case study extended to system and subsystem levels for each department.

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Investigation on brittle fracture mechanism of a grade E cast steel knuckle

A paper published on « Case Studies in Ingineering Failure Analysis », on april 2014.

This paper investigated the brittle fracture mechanism of a grade E cast steel knuckle that is one of the key components of the coupler for railway wagon. The fracture morphology mainly shows the characteristic of cleavage, quasi-cleavage fracture as well as a little ductile fracture, so the failure of the knuckle can be attributed to brittle fracture distinctly. Moreover, a welding repair area with high hardness is also found in the fracture region, which might initiate micro-cracks on the surface of the knuckle. As a result, it can be inferred that under an impact load that did not exceed material fracture limit, the micro-cracks initiated from weld repair zone propagated rapidly into the inner matrix by continuously fracturing the dendrites along shrinkage porosity regions until the knuckle failed instantly.

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Pitting corrosion failure analysis of a wet gas pipeline

This paper, published on Engineering Failure Analysis, august 2017, présents corrosion failure analysis of an underground natural gas pipeline. The pipeline material grade is API 5L X65 with 10-in ID. The pipeline transfers multiphase fluid (gas, condensate, and water) from a gas well to a gas gathering plant, located 4200 m away from the well site. A portion of the line failed due to pitting corrosion under unknown circumstances. Based on visual and microscopic analyses and reviewing the background information, the following pitting corrosion sequences were identified: the oversized pipeline changed the dominant flow regime to “stratified”. In the stratified flow regime, the accompanying water phase accumulated in the pipelines’ low points. Considerable concentration of calcium ions along with high pH in CO2 media favored precipitation of calcium carbonate. The relatively thick scales adhered to the pipe surface were partially loosened and removed by the regional turbulent flow. This exposed the fresh steel surface to the corrosive media. The uncovered areas acted as the preferential anodic sites coupled with nearby large cathodic sites which were covered by scales and/or corrosion products. Under such conditions, pits emerged on the steel surface until one of them grew faster and failed the gas pipeline.

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The Effects of Fiber Orientation and Volume Fraction of Fiber on Mechanical Properties of Additively Manufactured Composite Material

A thesis published by Conerstone : A Collection of Scholarly and Creative Works for Minnesota State University, Mankato.

Additive manufacturing (AM) also known as 3D printing has tremendous advancements in récent days with a vast number of applications in industrial, automotive, architecture, consumer projects, fashion, toys, food, art, etc. Composite materials are widely used in structures with weight as a critical factor especially in aerospace industry. Recently, additive manufacturing technology, a rapidly growing innovative technology, has gained lot of importance in making composite materials. The properties of composite materials depend upon the properties of constituent’s matrix and fiber. There is lot of research on effect of fiber orientation on mechanical properties of composite materials made using conventional manufacturing methods. It will be interesting and relevant to study the relationship between the fiber orientation and fiber volume with mechanical properties of additively manufactured composite materials. This thesis work presents experimental investigation of mechanical behavior like tensile strength and fatigue life with variation in fiber orientation and fiber volume fraction of 3D printed composite materials. The aim is to study the best combination of volume fraction of fiber and fiber orientation that has better fatigue strength for additive manufactured composite materials. Using this study, they can decide the type of orientation and volume percent for desired properties. This study also finds the range of fatigue limits of 3d printed composite materials .

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