Reduction in diversion due to coil break

A new case study, in « Case Studies, in Engeeniring Failure Analysis », Volume 2, Issue 2, October 2014, Pages 76–83.

Diversion due to coil break in cold rolled non oriented (CRNO) grades of coils showed an increasing trend during Jan–May’12 at Silicon Steel Mill (SSM), Rourkela Steel Plant (RSP). Coil break increased from a level of less than 1% during to a level of 30% in May’12. Further studies were carried out in the processing lines and material flow was tracked from steel making to final product. The probable reasons were identified and corrective measures were taken leading to reduction in diversion due to coil break less than 2%.

 Acceder article

Crack of a first stage blade in a steam turbine

A new Case Study in « Case Studies in Engineering Failure Analysis », Volume 2, Issue 2, October 2014, Pages 54–60

The failure of the first stage blade in a steam turbine of 55 MW was investigated. The blade was made of 17-4 PH stainless steel and has been used for 12 years before failure. The current work aims to find out the main cause of the first stage blade failure. The result showed that the crack at the blade root tang was due to corrosion fatigue and the crack occurred at the blade root fillet owing to stress corrosion cracking.

Acceder article

 

A detailed review and Prediction of Ductile Fracture

A publication in « IJRAME« , april 2014.

Earlier researchers were studied the failure analysis through various Failure Mode and Effective Analysis (FMEA) technique and tried to predict the fracture before failure occurs. This work attempts to predict the ductile fracture criterion for the sheet metal to avoid the failure by means of considering various controllable and uncontrollable parameters. With the Design of Experiments and the Artificial Neural Network techniques a ductile fracture initiation criteria modeled and the model will be validated through Finite element simulation for the verification of the quality. If comparison results are within the limit condition, the model can be utilized for the prediction of ductile fracture before it happens in the real application.

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EXPLOSION OF IRON HYDROGEN STORAGE CONTAINERS 120 YEARS AGO – Investigations Revisited

An interesting  publication in “Engineering Failure Analysis” available online 24 April 2014.

A nearly authentic translation of Adolf Martenś investigation report on the failure of numerous hydrogen storage cylinders is provided.

  • Explosion of the iron containers caused immense destruction on the air field Berlin-Tempelhof in 1894.
  • The translation reveals very detailed experimental procedures and at that time quite modern materials testing technologies.
  • The importance of Adolf Martens as a pioneer in conducting failure investigations becomes obvious.

Acceder article

An investigation into failure analysis of interfering part of a steam turbine journal bearing

A new Case Studies in Engineering Failure Analysis. Journal bearings as so sensitive parts of steam turbines are very susceptible to failure through different mechanisms of wear, fatigue and crush during service conditions. Failure occurring through these mechanisms lead to turbine completely shut down as a result of interfering in working conditions of bearing different parts. In this research, failed interfered part of a journal bearing related to a 320,000 kW steam turbine was examined. The studies were revealed that the bearing part loosing and inappropriate clearance can produce relative displacements under cyclic gradient loading. This condition was detrimental for the service life of turbine journal bearing via failure through fretting fatigue mechanism.

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La thermographie infrarouge active s’impose

La thermographie infrarouge active consiste à soumettre l’élément à contrôler à une excitation extérieure maîtrisée et à y analyser la propagation de la chaleur : les perturbations visualisées révèlent alors les éventuels défauts surfaciques ou subsurfaciques tels que fissures, délaminages, corrosion, inclusions d’eau ou d’éléments étrangers, etc. La formation du Cetim, sur deux jours, débute par la présentation des principes physiques de la méthode, les matériels utilisés, les types d’excitation, les logiciels de traitement d’image, les paramètres d’influence, etc.

La société Otecmi, a souhaité se former à la thermographie infrarouge active. Une technique bien adaptée à la détection des défauts dans les composites…

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Investigation of Minor Leakage in a Fuel Oil Return Line

A small fuel oil return line of a stationary gas turbine engine failed by high cycle fatigue cracking. In the metallurgical root cause investigation, performed by the original equipment manufacturer’s laboratory, it was determined that insufficient support of the fuel line and the ensuing vibration led to dynamic alternating bending stresses, that had their maximum immediately adjacent to the connector weld of the flange…………. Read more

Microscopy and C-Scan Techniques in the Study of Defects of CFRP Composites

A new article published in Practical Metallography: Vol. 51, No. 5, pp. 353-366.

Carbon Fiber Reinforced Plastic composites were fabricated through vacuum resin infusion technology by adopting two different processing conditions, viz., vacuum only in the first and vacuum plus external pressure in the next, in order to generate two levels of void-bearing samples. They were relatively graded as higher and lower void-bearing ones, respectively. Microscopy and C-scan techniques were utilized to describe the presence of voids arising from the two different processing parameters……….. Read more

FLEXURAL FATIGUE FAILURE ANALYSIS OF GLASS POLYESTER UNIDIRECTIONAL ANGLE PLY COMPOSITE LAMINATE

ijerstThis paper, published in « International Journal of Engineering Research and Science & Technology« , presents a study of the fatigue failure behavior of unidirectional angle ply composite laminate. Today a lot of research is directed to understand the fatigue failure behavior of laminated composites. These materials usage is increasing in all sorts of engineering applications due tohigh specific strength and stiffness, low weight and corrosion resistance. Fibre reinforced composite materials are selected for weight critical applications, due to good rating as per the fatigue failure is concerned and these materials are anisotropic in nature. The failure behavior made the study of these materials complicated………….

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Mécanique de la rupture fragile et de l’endommagement : approches statistiques et probabilistes

Cet ouvrage écrit par Jacques Lamon et édité par la Librairie Lavoisier, analyse le phénomène de la rupture fragile, son caractère aléatoire et les conséquences de la présence de populations de défauts dans les matériaux. Il présente les approches stochastiques de la rupture fragile et les méthodes de prévision sous des conditions diverses.  Lire la suite