Archives du mot-clef Failure analysis

A failure Study of a locking compression plate implant

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An interesting  paper in « Case study in Engineering Failure Analysis » published on ScienceDirect.com. In this case study a failed locking compression plate was investigated. Such plating systems are used to provide the stability to fractured bone and fixation. The locking compression plate had been separated in two pieces. One of the fracture surfaces from the failed component was investigated for surface topographical features. The visual, optical and scanning electron microscopy results indicated the presence of beach marks, intermetallic inclusions, corrosion pits and striations indicating fatigue crack propagation and overload failure. Some corrosion damage also was documented on the fractography. This case study shows that corrosion may have initiated fatigue crack which grew by the activities of daily living causing the failure.

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Failure Analysis of a Polymer Centrifugal Impeller

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A new case study published in Case Studies in Engineering Failure Analysis and posted on Sciencedirect.com.

The failure analysis investigation was performed on a fractured polymer impeller used in a respiratory blower. The brittle fracture morphology and defects within the impeller bore suggest that premature failure occurred because of multiple interacting factors including: intermittently high centrifugal velocities, imbalance bore and shaft conditions, defects within the bore caused by machining, and stress concentrations along the circumference of the impeller lip.

more at : Failure Analysis of a Polymer Centrifugal Impeller.

Corrosion Failures: Theory, Case Studies, and Solutions

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Corrosion FailuresUn ouvrage sur la corrosion, illustré de 80 cas d’analyses de défaillance va paraître le 8 mai 2015 chez l’éditeur John WILEY & Sons.

Pour en savoir plus : Corrosion Failures: Theory, Case Studies, and Solutions.

Premature Failure of Dissimilar Metal Weld Joint at Intermediate Temperature Superheater Tube

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A new case study on Sciencdirect.com. This article was published in « Case Studies in Engineering Failure Analysis » of april 2015.

Premature Failure of EPRI recommended nickel based filler for Dissimilar Metal welds (DMW) such as in the present study has been investigated to determine the root causes. The mechanism involved a creep stage I process on the alloy steel side due to improper PWHT leading to undesirable carbides precipitation increasing the hardness. Therefore, the sensitivity of the welding to micro-cracking combined to bending stresses involvement induced a premature failure within short time of operation.

Read more at : Premature Failure of Dissimilar Metal Weld Joint 

Failure Analysis of Work Rolls of a Thin Hot Strip Mill

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A new interesting article published in « Case Studies in Engineering Failure Analysis »

In hot rolling mills, premature failure of rolls is a major concern as it adversely affects the mill operation and as well as production. Analysis of failed roll materials and actual rolling conditions in service are therefore necessary to understand the roll failure mechanism and thereby improve the wear resistance and extend the service life of rolls.

This work describes two different types of roll failure cases and their analysis which was carried out using destructive as well as non-destructive testing techniques (NDT). The cases are as follows:

(a)

Case I: Enhanced ICDP Bottom roll of fifth stand (F#5) which failed from the neck portion.

(b)

Case II: Analysis of sub-surface defect of ICDP rolls of the last stand (F#6

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A study of the wear mechanisms of disk and shoe brake pads

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Un article paraître dans le numéro de fin janvier de la revue « Engineering Failure Analysis« . Il traite d’un cas d’analyse de défaillance d’un ensemble disque-mâchoire de frein usé en service.

Vous rencontrez un cas similaire, n’hésitez à pendre contact avec les experts en tribologie du Cetim. 11

Failure analysis of work rolls of a thin hot strip mill

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A new case study of failure analysis published on Sciencedirect.com

In hot rolling mills, premature failure of rolls is a major concern as it adversely affects the mill operation as well as production. Analysis of failed roll materials and actual rolling conditions in service are therefore necessary to understand the roll failure mechanism and thereby improve the wear resistance and extend the service life of rolls.

The hot strip mill referred here consists of six stands wherein high chromium (Hi-Cr) iron rolls and Indefinite Chilled Double Poured (ICDP) cast iron rolls are being used for finishing rolling of the strips in the last two stands. The thin strip mill produces strips in the thickness range of 1.0–12.7 mm. This work describes two different types of roll failure cases and their analysis which was carried out using destructive as well as non-destructive testing techniques (NDT).

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Flywheel Starter Ring Gear Failures

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A new case study in failure analysis published by ScienceDirect.com. This technical paper summarizes the case study conducted for truck flywheel starter ring gears with diameter of 470 mm in order to reduce hardness variation by optimization of induction hardening and tempering processes.

 

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Modes de ruine des réducteurs d’éoliennes

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2015-01-22_10h12_22Encore un article sur les éoliennes. Le site du NREL (laboratoire de l’U.S. Department of Energy) a posté un intéressant exposé  sous forme d’un diaporama dressant un tableau d’ensemble des modes de ruines possibles pour les réducteurs d’éoliennes. Télécharger le diaporama

Le Cetim a réalisé de nombreuses études sur les réducteurs d’éoliennes et se tient à votre disposition pour vous aider et vous conseiller pour prévenir les défaillances qui pourraient survenir. Pour en savoir plus suivez le lien.

Design and failure modes of automotive suspension springs

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An interesting publication in « Engineering Failure Analysis » of Decembre 2008. This paper is a discussion about automotive suspension coil springs, their fundamental stress distribution, materials characteristic, manufacturing and common failures. An in depth discussion on the parameters influencing the quality of coil springs is also presented.

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