Les emboutis profonds ne sont pas si fragiles

&Emboutis profondsDès 1988, le CETIM s’est attaché à définir les limites de déformation pour lesquelles une pièce emboutie à froid ne présente aucun risque de fragilité et peut donc être exemptée de traitement thermique. L’article paru en avril 1989 dans le numéro 110 de la revue CETIM-Informations vient d’être mis en ligne dans la Mecatech.

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Fracture analysis of wind turbine main shaft

Read on Engineering Failure Analysis. Shaft fracture at an early stage of operation is a common problem for a certain type of wind turbine. To determine the cause of shaft failure a series of experimental tests were conducted to evaluate the chemical composition and mechanical properties. The results show that stress concentration on the shaft surface close to the critical section of the shaft due to rubbing of the annular ring and coupled with high stress concentration caused by the change of inner diameter of the main shaft are the main reasons that result in fracture of the main shaft. The contribution of this paper is to provide a reference in fracture analysis of similar main shaft of wind turbines.

Leak-before-break for piping systems of fast breeder reactor

The Leak-Before-Break (LBB) concept has an effect on the safety design of Fast Breeder Reactors (FBRs), and thus its assessment has been one of the most significant issues. In the case of a commercial-scale FBR, since the main loads are the thermal expansion and thermal transient stresses, ferrite steel with a low thermal expansion rate has been a candidate material. A conventional LBB assessment method is insufficient to consider these characteristics, thus an advanced method is required.

  • The LBB assessment to ferrite pipes with thin walls and large diameters is proposed.
  • The surface resistance correction factor was improved for low-pressure.
  • The R6 method was applied to an unstable fracture assessment for postulated cracks.
  • A buckling assessment was introduced for the critical crack length for elbows.

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