Experimental and numerical inspection of cracks in ferrule cracking of BK1 cement crusher

This article defines the main actions planned in the procedure of non-destructive testing and analysis of defects in the BK1 industrial mill of the cement plant of the GICA group. One of the subjects attracting the attention of researchers and engineers was the propagation of cracks in the shell of the BK1 mill, which behaves like perforated plates. This inspection technique makes it possible to position and size defects (cracks) in the plates. The objective of this work is the detection of cracks in the shell of the BK1 cement mill. In order to avoid bursting of the crusher, the preventive technique of ultrasonic inspection using a multi-element translator is used, while minimizing downtime and increasing production. Found Results allow us to determine and analyze the different types of defects, which will be repaired. It was concluded that the stress concentration at the assembly holes, the vibration effects and gradient of the temperature due to the effect of welding were the causes great residual stresses at the level of the weld. We note the addition of a mass of weld during the repair of the cracks is one causes of the stress concentration

Numerical study of TRIP transformation in 35NCD16 steel-effects of plate orientation and some criteria

This study aims to analyze the effect of thermo mechanical coupling damage in the presence of a phase change (austenite/martensite) in 35NCD16 steel. The impact of increasing mechanical traction load, accompanied by a martensitic transformation on the scale of a single grain with boundary has been studied. The prediction transformation of induced plasticity (TRIP) was evaluated by taking into account the following parameters: twenty shear directions of the martensitic plates, two values of the shear deformation of the martensitic plates, energetic and thermodynamics criteria for getting in order the transformation of the martensitic plates, elastoplastic behavior of the two areas in the first case (martensitic plate and grain boundary) and elastic behavior for the grain boundary in the second case. The numerical calculation is carried out using the finite element method (FEM), implemented in the Zebulon calculation code. The developed approach is validated using the available experimental results reported in the literature. The numerical results showed that the estimation of TRIP given by the energetics criteria with the values of the shear deformation (γ0 = 0.16) are closer to the experiment results

Effect of Gaseous carburizing thermochemical treatment on tribological behavior of Ti–6Al–4V alloy

This study, concerns the improvement of the hardness and resistance to wear of the Ti-6Al-4V alloy surface by means of thermochemical treatment, for obtaining coatings on the Ti-6Al-4V alloy gives performance of resistance to wear phenomena. Three-thermochemical treatment time (2h, 4h, and 6h) was chosen for investigation of the effect of such treatment on this alloy. The hardness test under an indentation load of 50 gf with a Vickers pyramidal indenter revealed that the surface hardness is 335 Hv for the untreated samples. On the other hand the hardness reaches approximately 1500 Hv during gas cementation at 930 °C for variable times (2h, 4h, 6h) followed by quenching at 840 °C in an oil medium, which was accompanied by a significant improvement in wear resistance. The characterization of the modified surface layers was made by means of a microscopic analysis and by X-ray diffraction. The case-hardening made it possible to obtain a wear resistance greater than that of the alloy not treated, minimal loss of mass by dry friction and an improvement in roughness as well as a good coefficient of friction

Mechanical behavior and durability of fibre reinforced mortar in an aggressive environment

International audienceThis study was carried out to examine the mechanical behavior and durability of mortar with or without addition of silica fume, with and without steel fibre reinforcement. Three tests were carried out: strength, depth of pH reduction and micro-structural analysis by SEM. The mixes studied had two water cement ratios (0.5; 0.65); with a 0.5% steel fibre content and 10% silica fume content (in substitution of cement). To characterize the durability performance of the mortars studied, samples were exposed to one-year in three environments: wet environment (control samples under laboratory conditions, 20°C and 95% RH) and exposure samples: in cyclic environment (wetting and drying) and a sewage pumping station sump (an aggressive environment). SEM observations were carried out on samples to study the micro structural changes in the mortar's matrix. One sees the organic matter deposits located inside a pore and one can see the formation of the secondary ettringite. It is concluded that the compressive strength of the samples are relatively unaffected by mix type and environment. The samples exposed to sewage exhibited evidence a depth of pH reduction

On the effect of stiffness/softness and morphology of interphase phase on the effective elastic properties of three-phase composite material

In the present study, Composite material consisting of an elastic homogeneous isotropic matrix in which are embedded coated elastic isotropic inclusions, widely used in many applications is investigate by homogenization approach coupled to the finite elements method. A finite element model is proposed to predict the Young and Shear modulus of the three-phase composite containing spherical inclusions surrounded by a spherical or ellipsoid interphase layer. Three cases of particles volume fractions and interphase was considered with addition of two interphase morphology. Young modulus of interphase region was varied from soft to hard than the matrix properties. We note that interphase morphology and properties plays an important role in the elastic properties of composite with increasing the volume fraction of inclusions and interphase. The results were compared to the first order bounds Voigt and Reuss, and the mean field homogenization techniques. A sensitive study of the effect of mesh density on the results of the von Mises stresses and elastic properties has been made

Experimental and numerical inspection of cracks in ferrule cracking of BK1 cement crusher

This article defines the main actions planned in the procedure of non-destructive testing and analysis of defects in the BK1 industrial mill of the cement plant of the GICA group. One of the subjects attracting the attention of researchers and engineers was the propagation of cracks in the shell of the BK1 mill, which behaves like perforated plates. This inspection technique makes it possible to position and size defects (cracks) in the plates. The objective of this work is the detection of cracks in the shell of the BK1 cement mill. In order to avoid bursting of the crusher, the preventive technique of ultrasonic inspection using a multi-element translator is used, while minimizing downtime and increasing production. Found Results allow us to determine and analyze the different types of defects, which will be repaired. It was concluded that the stress concentration at the assembly holes, the vibration effects and gradient of the temperature due to the effect of welding were the causes great residual stresses at the level of the weld. We note the addition of a mass of weld during the repair of the cracks is one causes of the stress concentration

Un Nouveau Concept Baser Sur La Métallurgie Des Poudres Et Le Calcul Eléments Finis Pour Les Produits Biocompatibles

Résumé- Une nouvelle méthode de conception des produits biocompatibles comme les prothèses totales de hanche, est proposée. Des paramètres techniques sont prisent en compte sur le plan géométrique (design) et surtout sur le plan de matériau et calcul de résistance pour assurer la biocompatibilité de ce dernier. Cette méthodologie va permettre un gain en temps et en qualité.Mots clés- design, mode d’obtention, La métallurgie des poudres, processus, calcul de résistance, biomatériau, biocompatibilité

Development of Numerical Method for Optimizing Silicon Solar Cell Efficiency

This paper presents a development of numerical method to determine and optimize the photocurrent densities in silicon solar cell. This method is based on finite difference algorithm to resolve the continuity and Poisson equations of minority charge carriers in p-n junction regions by using Thoma’s algorithm to resolve the tridiagonal matrix. These equations include several physical parameters as the absorption coefficient and the reflection one of the material under the sunlight irradiation of AM1.5 solar spectrum. In this work, we study the effect of various parameters such as thickness and doping concentration of the (emitter, base) layers on crystalline silicon solar cell perfomance. The obtained results show that the optimum energy conversion efficiency is 22.16 % with the following electrical parameters solar cell Voc = 0.62 V and Jph = 43.20 mA · cm – 2. These results are compared with experimental data and show a good agreement of our developped method

L’Utilisation de L’Alliage CoCrMo En Biomécanique (cas de prothèse discal)

Les paramètres pour la production de la métallurgie des poudres classique d'un alliage CoCrMo pour les prothèses orthopédiques sont déterminés. Avec l'application de ces paramètres, un alliage ayant une densité à l’état brute, une faible porosité après frittage, la dureté considérable et comportement passif avec une résistance de frottement imporante

Durabilité des bétons fibrés conservés en réseau d'assainissement

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