4 Cas Concrets de ruptures

Avatar Cas ConcretsQuatre cas d’analyses de défaillances par ruptures survenues sur des organes de machines de divers horizons : un tirant de palier, un arbre de roue, un corps de piston et un corps d’amortisseur de tampon de wagon ferroviaire.

Ces quatre fiches d’analyse de défaillances avaient été publiées en avril 1987 dans le numéro 100 de la revue Cetim-information. Elles sont toujours d’actualité.

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

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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Fatigue Failure of Aluminium Alloy Piston

An article published in International Research Journal of Engineering and Technology (IRJET), Volume: 03 Issue: 04 | Apr-2016.
pistonAn analytical study was performed about piston failure by fatigue. Fatigue cracks are initiated and propagated by the action of mechanical and high temperature loading conditions which induces cyclic stresses in the piston material.  Various proposals and solutions are presented so that necessary care can be taken to prevent piston failure in future.

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Cas Concrets – piston, axe, arbre et membrane

Avatar Cas ConcretsQuatre nouvelles fiches traitant de cas d’analyses de défaillances survenues en service ont été postées dans la Mécatech du Cetim : un piston de moule d’injection, un axe de pince de manutention, un arbre cannelé de réducteur et une membrane vibrante de système hydraulique.

Ces fiches d’analyse de défaillance avaient été publiées entre 1984 et 1986 dans la revue Cetim-information.

Failure in automotive steering system hydraulic cylinder

www.dtbtest.com/PDFs/steering-system-hydraulic-cylinder-failure.pdf

Description : Failure in automotive steering system hydraulic cylinder
Problem : Piston failures in reduced section transition radius
Analysis : Superimposed stress concentrations due to transition radius and machining marks resulted in circumferential fatigue crack initiation. Was followed by brittle crack propagation due to notch effects.
Resolution & Recommendations :
Modify microstructure from norm. to Q&T and shot peen transition radius to eliminate fatigue crack initiation