Simulation et quantification tridimensionnelledes défauts générés par un processus de fabrication

The manufacturing dimensioning intends to determine the intermediary geometrical and dimensional state of the part during its manufacturing process. This manufacturing dimension also permits to respect the functional requirements given by the design drawing on one hand, and the manufacturing constraints on the other (the machine precision, minimal machining extra thickness...). The TMT method (Three-dimensional Manufacturing Tolerancing) is a three-dimensional approach of manufacturing dimensioning with the concept of small displacements torsor. This approach permits to treat the specification to definition drawing defined by the ISO norms. The purpose is to analyse the impact of the manufacturing deviations on each specification to be considered. This method uses a precise definition of the reference systems in each phase in correlation with the machine adjustment process. The nominal part model is directly fixtured on the datum system of the studied requirement so as to minimize the number of the unknowns. This approach puts into evidence the obtained calculation simplifications, which permits a simple writing of the dimensions chains resultant to verify each requirement.La cotation de fabrication a pour but de déterminer l'état géométrique et dimensionnel intermédiaire de la pièce tout au long de son processus de fabrication. Pour respecter, d'une part, les exigences fonctionnelles données par le dessin de définition et, d'autre part, les contraintes de fabrication (précision de la machine, surépaisseurs minimales d'usinage,...). La méthode TMT (Tridimensional Manufacturing Tolerancing) est une approche tridimensionnelle de cotation de fabrication avec le concept du torseur de petits déplacements. Cette approche permet de traiter les spécifications des dessins de définition exprimées par les normes ISO. Le but est d'analyser l'influence de tous les écarts de fabrication sur chaque spécification à respecter. Cette méthode utilise une définition précise des systèmes de références dans chaque phase en corrélation avec le processus de réglage des machines. Le modèle nominal de la pièce est positionné directement sur le système de références de l'exigence étudiée, afin de minimiser le nombre d'inconnues. Cette approche met en évidence les simplifications de calcul ainsi obtenues, ce qui permet une écriture assez simple de la résultante de la chaîne de cotes pour vérifier chaque exigence

Simulation et quantification tridimensionnelle des défauts générés par un processus de fabrication

La cotation de fabrication a pour but de déterminer l'état géométrique et dimensionnel intermédiaire de la pièce tout au long de son processus de fabrication. Pour respecter, d'une part, les exigences fonctionnelles données par le dessin de définition et, d'autre part, les contraintes de fabrication (précision de la machine, surépaisseurs minimales d'usinage,...). La méthode TMT (Tridimensional Manufacturing Tolerancing) est une approche tridimensionnelle de cotation de fabrication avec le concept du torseur de petits déplacements. Cette approche permet de traiter les spécifications des dessins de définition exprimées par les normes ISO. Le but est d'analyser l'influence de tous les écarts de fabrication sur chaque spécification à respecter. Cette méthode utilise une définition précise des systèmes de références dans chaque phase en corrélation avec le processus de réglage des machines. Le modèle nominal de la pièce est positionné directement sur le système de références de l'exigence étudiée, afin de minimiser le nombre d'inconnues. Cette approche met en évidence les simplifications de calcul ainsi obtenues, ce qui permet une écriture assez simple de la résultante de la chaîne de cotes pour vérifier chaque exigence.The manufacturing dimensioning intends to determine the intermediary geometrical and dimensional state of the part during its manufacturing process. This manufacturing dimension also permits to respect the functional requirements given by the design drawing on one hand, and the manufacturing constraints on the other (the machine precision, minimal machining extra thickness...). The TMT method (Three-dimensional Manufacturing Tolerancing) is a three-dimensional approach of manufacturing dimensioning with the concept of small displacements torsor. This approach permits to treat the specification to definition drawing defined by the ISO norms. The purpose is to analyse the impact of the manufacturing deviations on each specification to be considered. This method uses a precise definition of the reference systems in each phase in correlation with the machine adjustment process. The nominal part model is directly fixtured on the datum system of the studied requirement so as to minimize the number of the unknowns. This approach puts into evidence the obtained calculation simplifications, which permits a simple writing of the dimensions chains resultant to verify each requirement.CACHAN-ENS (940162301) / SudocSudocFranceF

Experimental force measurements in single point incremental sheet forming SPIF

This paper provides the experimental protocol, of the process of a single point incremental sheet forming “SPIF”, allowing predicting the efforts of forming. To speak about parameters of a single point incremental sheet forming (SPIF), we should find the good parameter for judgement. A prediction of the forming force during the SPIF process is selected to ensure the safe use of the tooling and machinery, in particular when using a robot or a milling machine not designed for the process. During the incremental forming process, considerable forces can occur depending on the studied material, the thickness of the sheet, the tool steps. In this work, the influence of several parameters on the evolution of the axial forming force during the incremental forming of a truncated cone is studied. A set of experiments is carried out using steel and aluminium sheets. The results on the most influent process parameters can be used to optimize the process. The results obtained are compared with those found by finite element simulations

A CFD modelling on effects of ejection angle of a co-flow on the thermal characteristics for a combined wall and offset jet flow

In the present study, a CFD simulation of a flow combined an offset jet and a wall jet (noted dual-jet) with the presence of co-flow is carried out. The effect of the intensity of the co-flow CFV (co-flow velocity) as well as its ejection angle α on the heat transfer exchanged in dual-jet flow is also performed. The present simulations are carried out for a Reynolds number Re = 15000, a nozzle-to-nozzle distance equal to 4 times the thickness of the nozzle, a co-flow velocity CFV = 10% − 40 % and a co-flow ejection angle α = 0° − 40°. The results of this computational study clearly show an intensification of the heat transfer exchanged between the flow and the wall by increasing the co-flow velocity CFV as well as its ejection angle α

Jet Impingement Cooling of a Rotating Hot Circular Cylinder with Hybrid Nanofluid under Multiple Magnetic Field Effects

The cooling performance of jet impinging hybrid nanofluid on a rotating hot circular cylinder was numerically assessed under the effects of multiple magnetic fields via finite element method. The numerical study was conducted for different values of Reynolds number (100≤Re≤300), rotational Reynolds number (0≤Rew≤800), lower and upper domain magnetic field strength (0≤Ha≤20), size of the rotating cylinder (2 w ≤r≤ 6 w) and distance between the jets (6 w ≤ H ≤ 16 w). In the presence of rotation at the highest speed, the Nu value was increased by about 5% when Re was increased from Re = 100 to Re = 300. This value was 48.5% for the configuration with the motionless cylinder. However, the rotations of the cylinder resulted in significant heat transfer enhancements in the absence or presence of magnetic field effects in the upper domain. At Ha1 = 0, the average Nu rose by about 175%, and the value was 249% at Ha1 = 20 when cases with the cylinder rotating at the highest speed were compared to the motionless cylinder case. When magnetic field strengths of the upper and lower domains are reduced, the average Nu decreases. The size of the cylinder is influential on the flow dynamics and heat transfer when the cylinder is rotating. An optimum value of the distance between the jets was obtained at H = 14 w, where the Nu value was highest for the rotating cylinder case. A modal analysis of the heat transfer dynamics was performed with the POD technique. As diverse applications of energy system technologies with impinging jets are available, considering the rotations of the cooled surface under the combined effects of using magnetic field and nanoparticle loading in heat transfer fluid is a novel contribution. The outcomes of the present work will be helpful in the initial design and optimization studies in applications from electronic cooling to convective drying, solar power and many other systems

Multi-criteria/comparative analysis and multi-objective optimization of a hybrid solar/geothermal source system integrated with a carnot battery

Among the different electrical energy storage technologies, the Carnot batteries are promising options with low specific cost that do not suffer from geographical limitations and power-capacity coupling. In addition to power balancing, this approach can also be unique for multi-vector energy management. A comprehensive evaluation (thermodynamic design and exergoenvironmental and exergoeconomic evaluations), comparison, and multi-objective optimization of four Carnot battery configurations based on solar-electric energy and a geothermal source is presented. Geothermal energy can simultaneously improve the thermodynamic and environmental performances of the Carnot battery. The main structure of all configurations is based on electrical energy obtained from PV and captured thermal energy from a geothermal source. The four Brayton, heat pump, flash, and organic Rankine cycle (ORC) units are periodically integrated. The outcomes point out that the discharging process is based on an ORC unit and a flash-heat pump cycle (F-HPC)-based charging process makes more optimal heat-to-power efficiency. Moreover, the Carnot battery based on the regenerative-Brayton cycle (R-BC) unit has a higher investment cost rate compared to the ORC unit (in the discharging process). When integrating the geothermal, the third configuration (R-HPC/R-BC) experiences the greatest improvement (5.3-fold) due to the increase in thermal energy received from the geothermal source

A Novel Approach of Optimum Time Interval Estimation for Al-7.5Si/Al-18Si Liquid–Liquid Bimetal Casting in Sand and Metallic Moulds

This work describes a novel approach for Al-7.5Si/Al-18Si liquid–liquid bimetal casting in sand and metallic moulds. The aim of the work is to facilitate and develop a simple procedure to produce an Al-7.5Si/Al-18Si bimetallic material with a smooth gradient interface structure. The procedure involves the theoretical calculation of total solidification time (TST) of the first liquid metal (M1), pouring the liquid metal (M1), and allowing it to solidify; then, before complete solidification, the second liquid metal (M2) is introduced into the mould. This novel approach has been proven to produce Al-7.5Si/Al-18Si bimetal materials using liquid–liquid casting. The optimum time interval of Al-7.5Si/Al-18Si bimetal casting with modulus of cast Mc ≤ 1 was estimated based on subtracting 5–15 s or 1–5 s from TST of M1 for sand and metallic moulds, respectively. Future work will involve determining the appropriate time interval range for castings having modulus ≥ 1 using the current approach

CFD Study of MHD and Elastic Wall Effects on the Nanofluid Convection Inside a Ventilated Cavity Including Perforated Porous Object

Cost-effective, lightweight design alternatives for the thermal management of heat transfer equipment are required. In this study, porous plate and perforated-porous plates are used for nanoliquid convection control in a flexible-walled vented cavity system under uniform magnetic field effects. The finite element technique is employed with the arbitrary Lagrangian–Eulerian (ALE) method. The numerical study is performed for different values of Reynolds number (200≤Re≤1000), Hartmann number (0≤Ha≤50), Cauchy number (10−8≤Ca≤10−4) and Darcy number (10−6≤Da≤0.1). At Re = 600, the average Nusselt number (Nu) is 6.3% higher by using a perforated porous plate in a cavity when compared to a cavity without a plate, and it is 11.2% lower at Re = 1000. At the highest magnetic field strength, increment amounts of Nu are in the range of 25.4–29.6% by considering the usage of plates. An elastic inclined wall provides higher Nu, while thermal performance improvements in the range of 3.6–6% are achieved when varying the elastic modulus of the wall. When using a perforated porous plate and increasing its permeability, 22.8% increments of average Nu are obtained. A vented cavity without a plate and elastic wall provides the highest thermal performance in the absence of a magnetic field, while using a porous plate with an elastic wall results in higher Nu when a magnetic field is used

CFD Study of MHD and Elastic Wall Effects on the Nanofluid Convection Inside a Ventilated Cavity Including Perforated Porous Object

Cost-effective, lightweight design alternatives for the thermal management of heat transfer equipment are required. In this study, porous plate and perforated-porous plates are used for nanoliquid convection control in a flexible-walled vented cavity system under uniform magnetic field effects. The finite element technique is employed with the arbitrary Lagrangian–Eulerian (ALE) method. The numerical study is performed for different values of Reynolds number (200≤Re≤1000), Hartmann number (0≤Ha≤50), Cauchy number (10−8≤Ca≤10−4) and Darcy number (10−6≤Da≤0.1). At Re = 600, the average Nusselt number (Nu) is 6.3% higher by using a perforated porous plate in a cavity when compared to a cavity without a plate, and it is 11.2% lower at Re = 1000. At the highest magnetic field strength, increment amounts of Nu are in the range of 25.4–29.6% by considering the usage of plates. An elastic inclined wall provides higher Nu, while thermal performance improvements in the range of 3.6–6% are achieved when varying the elastic modulus of the wall. When using a perforated porous plate and increasing its permeability, 22.8% increments of average Nu are obtained. A vented cavity without a plate and elastic wall provides the highest thermal performance in the absence of a magnetic field, while using a porous plate with an elastic wall results in higher Nu when a magnetic field is used