The electromagnetic forming is a process to manufacture a part from sheet metal. The final shape ... more The electromagnetic forming is a process to manufacture a part from sheet metal. The final shape of the part depends on the geometry of the dies, the material behaviour of the workpiece and the process parameters. This paper describes magnetic field transient analysis into electromagnetic forming devices using the finite element method (FEM). The electromagnetic force which causes plastic deformation
Electromagnetic forming is applied to form metal sheet parts from both non-ferrous and ferrous ma... more Electromagnetic forming is applied to form metal sheet parts from both non-ferrous and ferrous materials. In this paper, the electromagnetic forming behavior of aluminum alloy, copper and steel sheets was investigated through experiments. The disk-shaped specimens were electromagnetically free bulged with increasing deformation energies and parts with different deformation depths were obtained. The deformation was done with and without clamping the movement of the specimens’ edges. The specimens were printed with a mesh of diametrical lines and concentric circles with a predetermined pitch. The mesh served to determine the displacements in the mesh nodes after the deformation of the specimens, with which the axial, radial and circumferential strains were then calculated. The experimental data obtained was subjected to statistical correlation and regression analyses, and the mathematical models for the three main strains in each material were established. The strains of AlMn0.5Mg0.5 ...
ABSTRACT The most interesting and studied materials for practical applications of colossal magnet... more ABSTRACT The most interesting and studied materials for practical applications of colossal magnetorsistance effect are rare earth manganites with general formula RMnO3RMnO3 (where R is a rare/alkaline earth element). The coexisting of competing phases in manganites, such as metallic ferromagnetic, charge ordered, antiferromagnetic insulating and ferromagnetic insulating phases, determines an important change of magnetic and transport properties with the microstructure. In this paper, we report on the correlations between microstructural, magnetic and transport properties at temperatures ranging from 263 to 343 K of La0.5Pr0.2Pb0.3-xSrxMnO3La0.5Pr0.2Pb0.3-xSrxMnO3 manganites synthesized by ceramic technology. The microstructure is studied using X-ray diffraction (XRD), small-angle X-ray scattering (SAXS) and small-angle neutron scattering (SANS) at Sr concentrations x=0.00,0.05,0.15x=0.00,0.05,0.15 and 0.20. SAXS and SANS data show the formation of magnetic nanodomains in the mosaic blocks, at temperatures higher than Curie temperature TCTC. SANS data reveal the shape and concentration of magnetic nanodomains, and their dependency on temperature. The La0.5Pr0.2Pb0.3-xSrxMnO3La0.5Pr0.2Pb0.3-xSrxMnO3 manganites crystallize as cubic structure Pm3¯m (x=0.00x=0.00 and x=0.05x=0.05) or as rhombohedral structure R3¯c (x=0.15x=0.15 and x=0.20x=0.20). We found that transport phenomena at temperatures higher than TCTC are greatly influenced by nanodomains concentration and their shape. We show that about room temperature manganites with x=0.05x=0.05 and x=0.15x=0.15 have large intrinsic resistance maxima, generating an important magnetoresistance effect.
Proposed and accomplished finite element simulations in this paper started from the idea that mat... more Proposed and accomplished finite element simulations in this paper started from the idea that materials which are plastically deformed and those from which electromagnetic deformation devices are built can influence the development of transitory magnetic phenomenon during the working process. Workpieces from paramagnetic, diamagnetic and ferromagnetic materials and devices that contain metallic and non-metallic materials were taken into study. FLUX2D modelling and simulating software was used to achieve numerical values and graphical images for the main process parameters: magnetic induction and magnetic pressure (of deformation). A finite element model, previously validated through experiment, was used to perform the simulations in order to assure a high degree of accuracy for the presented results.
The dimensional effect of electric charge storage with a density of up to 270 μF/g by the hydrate... more The dimensional effect of electric charge storage with a density of up to 270 μF/g by the hydrated ZrO2-nanoparticles system was determined. It was found that the place of localization of different charge carriers is the generalized heterophase boundary-nanoparticles surface. The supposed mechanism of the effect was investigated using the theory of dispersed systems, the band theory, and the theory of contact phenomena in semiconductors, which consists of the formation of localized electronic states in the nanoparticle material due to donor–acceptor interaction with the adsorption ionic atmosphere. The effect is relevant for modern nanoelectronics, microsystem technology, and printed electronics because it allows overcoming the basic physical restrictions on the size, temperature, and operation frequency of the device, caused by leakage currents.
The dimensional effect of the accumulation of an electric charge with a density of up to 270 μF/g... more The dimensional effect of the accumulation of an electric charge with a density of up to 270 μF/g by the system of compacted zirconium dioxide nanoparticles during exposure in an electric field (5000 V/m) under normal physical conditions is determined. Based on a qualitative complex analysis of the forms of appearance of the effect, it is shown that the place of localization of different charge carriers is the surface of nanoparticles. The supposed mechanism of this effect is considered using the theory of dispersed systems, the band theory, and the theory of contact phenomena in semiconductors. It was concluded that this mechanism is due to the phenomenon of localization of electron-type charge nanoparticles in the near-surface zone of the material in contact with the adsorption ion atmosphere. This effect is relevant for modern nanoelectronics, microsystem technology, and printed electronics.
The objective of this paper is to discuss the possibility of using electromagnetic tools to manuf... more The objective of this paper is to discuss the possibility of using electromagnetic tools to manufacture of religious objects from metal by plastic deformation. The paper analyzes a very agile manufacturing method based on only one tool (a die) that gives shape to the desired part and on the action of electromagnetic force that can be applied to manufactured metal objects such as open boxes, frames, religious objects, etc. that may have surfaces with embossed details. Electromagnetic forming is a method that allows a pressure impulse to be directed to a part of metal sheet in a highly controlled and reproducible manner. The electromagnetic tool (a coil) configuration controls the spatial distribution of the deforming pressure and the energy stored in a capacitor bank controls the impulse size transmitted to the material that will be deformed.
Electromagnetic forming is an advanced manufacturing procedure, characterized by the fact that th... more Electromagnetic forming is an advanced manufacturing procedure, characterized by the fact that the tool carrying the deformation force does not touch the workpiece. This paper presents research regarding the electromagnetic forming of Al 99.0 (EN AW-1200) sheet with coils, having different configurations. The purpose of the research was to find the flat spiral coil configuration that ensures maximum deformation of the workpiece. Flat spiral coils with different gaps between the coil and the workpiece, and coils with different number of windings were tested. The influence of these parameters was monitored on the maximum strain of the free bulged parts. The analysis of the results obtained for different configurations of the flat spiral coils allowed the selection of the significant parameters that influenced the electromagnetic forming process of the Al 99.0 flat workpiece, which aimed to elaborate the mathematical model and to optimize the investigated process.
Thermal depositions are very wide spread in the industry of coating techniques. The materials use... more Thermal depositions are very wide spread in the industry of coating techniques. The materials used as coatings for several applications must have the ability to produce a stable, slow-growing surface coating, in order to provide good service behavior. This paper presents a method to increase the wear resistance of steering pump cam, strongly stressed having premature wear effects. The method that the authors use is atmospheric plasma deposition with Ni-Cr-Fe and Ni-Cr-B-Fe powders on steel substrate. It was investigated the morphology and physico-mechanical properties (scratch and micro-indentation analysis). Results showed a comparison between those two coatings with the metallic substrate. It has been found that the deposited coatings have an adherent, dense and uniform layer with a typically molten morphology. By increasing the coefficient of friction we can obtain higher wear resistance and recommend the optimum solution for further researches.
The International Journal of Advanced Manufacturing Technology, 2015
An electromagnetic forming process of FeP04 steel sheets is studied over a wide range of variatio... more An electromagnetic forming process of FeP04 steel sheets is studied over a wide range of variation of technological parameters aiming at finding optimal values providing maximum deformation of the part. The process parameters considered in this paper are deformed part diameter (d), thickness of specimen (t), distance coil–specimen (D), number of coil turns (N), capacitance of capacitor bank (C), and the charging voltage (V). Each specimen was freely deformed on a die of ring type through a unique combination of input parameters included in the study, and the maximum depth of the deformed parts center (h) was considered output parameter. Radial basis function neural networks are used for modeling the functional dependence between technological parameters and the resulting deformation of the material. Modeling results indicate an average mean square error around 4 % and a correlation between experimental data and neural model output exceeding 0.99. Sensitivity analysis reveals significant input parameters that decisively influence the output of the model. Simulation results are in good agreement with the experimental data, suggesting that neural networks can be considered a viable modeling alternative to existing approaches.
The electromagnetic forming is a process to manufacture a part from sheet metal. The final shape ... more The electromagnetic forming is a process to manufacture a part from sheet metal. The final shape of the part depends on the geometry of the dies, the material behaviour of the workpiece and the process parameters. This paper describes magnetic field transient analysis into electromagnetic forming devices using the finite element method (FEM). The electromagnetic force which causes plastic deformation
Electromagnetic forming is applied to form metal sheet parts from both non-ferrous and ferrous ma... more Electromagnetic forming is applied to form metal sheet parts from both non-ferrous and ferrous materials. In this paper, the electromagnetic forming behavior of aluminum alloy, copper and steel sheets was investigated through experiments. The disk-shaped specimens were electromagnetically free bulged with increasing deformation energies and parts with different deformation depths were obtained. The deformation was done with and without clamping the movement of the specimens’ edges. The specimens were printed with a mesh of diametrical lines and concentric circles with a predetermined pitch. The mesh served to determine the displacements in the mesh nodes after the deformation of the specimens, with which the axial, radial and circumferential strains were then calculated. The experimental data obtained was subjected to statistical correlation and regression analyses, and the mathematical models for the three main strains in each material were established. The strains of AlMn0.5Mg0.5 ...
ABSTRACT The most interesting and studied materials for practical applications of colossal magnet... more ABSTRACT The most interesting and studied materials for practical applications of colossal magnetorsistance effect are rare earth manganites with general formula RMnO3RMnO3 (where R is a rare/alkaline earth element). The coexisting of competing phases in manganites, such as metallic ferromagnetic, charge ordered, antiferromagnetic insulating and ferromagnetic insulating phases, determines an important change of magnetic and transport properties with the microstructure. In this paper, we report on the correlations between microstructural, magnetic and transport properties at temperatures ranging from 263 to 343 K of La0.5Pr0.2Pb0.3-xSrxMnO3La0.5Pr0.2Pb0.3-xSrxMnO3 manganites synthesized by ceramic technology. The microstructure is studied using X-ray diffraction (XRD), small-angle X-ray scattering (SAXS) and small-angle neutron scattering (SANS) at Sr concentrations x=0.00,0.05,0.15x=0.00,0.05,0.15 and 0.20. SAXS and SANS data show the formation of magnetic nanodomains in the mosaic blocks, at temperatures higher than Curie temperature TCTC. SANS data reveal the shape and concentration of magnetic nanodomains, and their dependency on temperature. The La0.5Pr0.2Pb0.3-xSrxMnO3La0.5Pr0.2Pb0.3-xSrxMnO3 manganites crystallize as cubic structure Pm3¯m (x=0.00x=0.00 and x=0.05x=0.05) or as rhombohedral structure R3¯c (x=0.15x=0.15 and x=0.20x=0.20). We found that transport phenomena at temperatures higher than TCTC are greatly influenced by nanodomains concentration and their shape. We show that about room temperature manganites with x=0.05x=0.05 and x=0.15x=0.15 have large intrinsic resistance maxima, generating an important magnetoresistance effect.
Proposed and accomplished finite element simulations in this paper started from the idea that mat... more Proposed and accomplished finite element simulations in this paper started from the idea that materials which are plastically deformed and those from which electromagnetic deformation devices are built can influence the development of transitory magnetic phenomenon during the working process. Workpieces from paramagnetic, diamagnetic and ferromagnetic materials and devices that contain metallic and non-metallic materials were taken into study. FLUX2D modelling and simulating software was used to achieve numerical values and graphical images for the main process parameters: magnetic induction and magnetic pressure (of deformation). A finite element model, previously validated through experiment, was used to perform the simulations in order to assure a high degree of accuracy for the presented results.
The dimensional effect of electric charge storage with a density of up to 270 μF/g by the hydrate... more The dimensional effect of electric charge storage with a density of up to 270 μF/g by the hydrated ZrO2-nanoparticles system was determined. It was found that the place of localization of different charge carriers is the generalized heterophase boundary-nanoparticles surface. The supposed mechanism of the effect was investigated using the theory of dispersed systems, the band theory, and the theory of contact phenomena in semiconductors, which consists of the formation of localized electronic states in the nanoparticle material due to donor–acceptor interaction with the adsorption ionic atmosphere. The effect is relevant for modern nanoelectronics, microsystem technology, and printed electronics because it allows overcoming the basic physical restrictions on the size, temperature, and operation frequency of the device, caused by leakage currents.
The dimensional effect of the accumulation of an electric charge with a density of up to 270 μF/g... more The dimensional effect of the accumulation of an electric charge with a density of up to 270 μF/g by the system of compacted zirconium dioxide nanoparticles during exposure in an electric field (5000 V/m) under normal physical conditions is determined. Based on a qualitative complex analysis of the forms of appearance of the effect, it is shown that the place of localization of different charge carriers is the surface of nanoparticles. The supposed mechanism of this effect is considered using the theory of dispersed systems, the band theory, and the theory of contact phenomena in semiconductors. It was concluded that this mechanism is due to the phenomenon of localization of electron-type charge nanoparticles in the near-surface zone of the material in contact with the adsorption ion atmosphere. This effect is relevant for modern nanoelectronics, microsystem technology, and printed electronics.
The objective of this paper is to discuss the possibility of using electromagnetic tools to manuf... more The objective of this paper is to discuss the possibility of using electromagnetic tools to manufacture of religious objects from metal by plastic deformation. The paper analyzes a very agile manufacturing method based on only one tool (a die) that gives shape to the desired part and on the action of electromagnetic force that can be applied to manufactured metal objects such as open boxes, frames, religious objects, etc. that may have surfaces with embossed details. Electromagnetic forming is a method that allows a pressure impulse to be directed to a part of metal sheet in a highly controlled and reproducible manner. The electromagnetic tool (a coil) configuration controls the spatial distribution of the deforming pressure and the energy stored in a capacitor bank controls the impulse size transmitted to the material that will be deformed.
Electromagnetic forming is an advanced manufacturing procedure, characterized by the fact that th... more Electromagnetic forming is an advanced manufacturing procedure, characterized by the fact that the tool carrying the deformation force does not touch the workpiece. This paper presents research regarding the electromagnetic forming of Al 99.0 (EN AW-1200) sheet with coils, having different configurations. The purpose of the research was to find the flat spiral coil configuration that ensures maximum deformation of the workpiece. Flat spiral coils with different gaps between the coil and the workpiece, and coils with different number of windings were tested. The influence of these parameters was monitored on the maximum strain of the free bulged parts. The analysis of the results obtained for different configurations of the flat spiral coils allowed the selection of the significant parameters that influenced the electromagnetic forming process of the Al 99.0 flat workpiece, which aimed to elaborate the mathematical model and to optimize the investigated process.
Thermal depositions are very wide spread in the industry of coating techniques. The materials use... more Thermal depositions are very wide spread in the industry of coating techniques. The materials used as coatings for several applications must have the ability to produce a stable, slow-growing surface coating, in order to provide good service behavior. This paper presents a method to increase the wear resistance of steering pump cam, strongly stressed having premature wear effects. The method that the authors use is atmospheric plasma deposition with Ni-Cr-Fe and Ni-Cr-B-Fe powders on steel substrate. It was investigated the morphology and physico-mechanical properties (scratch and micro-indentation analysis). Results showed a comparison between those two coatings with the metallic substrate. It has been found that the deposited coatings have an adherent, dense and uniform layer with a typically molten morphology. By increasing the coefficient of friction we can obtain higher wear resistance and recommend the optimum solution for further researches.
The International Journal of Advanced Manufacturing Technology, 2015
An electromagnetic forming process of FeP04 steel sheets is studied over a wide range of variatio... more An electromagnetic forming process of FeP04 steel sheets is studied over a wide range of variation of technological parameters aiming at finding optimal values providing maximum deformation of the part. The process parameters considered in this paper are deformed part diameter (d), thickness of specimen (t), distance coil–specimen (D), number of coil turns (N), capacitance of capacitor bank (C), and the charging voltage (V). Each specimen was freely deformed on a die of ring type through a unique combination of input parameters included in the study, and the maximum depth of the deformed parts center (h) was considered output parameter. Radial basis function neural networks are used for modeling the functional dependence between technological parameters and the resulting deformation of the material. Modeling results indicate an average mean square error around 4 % and a correlation between experimental data and neural model output exceeding 0.99. Sensitivity analysis reveals significant input parameters that decisively influence the output of the model. Simulation results are in good agreement with the experimental data, suggesting that neural networks can be considered a viable modeling alternative to existing approaches.
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