The Experts below are selected from a list of 306 Experts worldwide ranked by ideXlab platform
Glenn S. Daehn - One of the best experts on this subject based on the ideXlab platform.
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Vaporizing foil actuator welding
Mrs Bulletin, 2019Co-Authors: Brian P. Thurston, Anupam Vivek, Bhuvi S.l. Nirudhoddi, Glenn S. DaehnAbstract:Vaporizing foil actuator welding is a form of impact welding, which can be carried out without the use of chemical explosives. Operating at smaller length scales, but with similar driving pressures as explosive welding, Vaporizing foil actuator welding is capable of welding a wide variety of advanced and dissimilar metal combinations. With negligible heating developing during the process, thermal distortion does not occur, and the base-metal properties are retained in the weld. In this article, Vaporizing foil actuator welding of an automotive grade aluminum and steel pair is discussed. A currently functional and complete welding system that can be used for research as well as low volume production is also discussed.
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Numerical investigation of CP-Ti & Cu110 impact welding using smoothed particle hydrodynamics and arbitrary Lagrangian-Eulerian methods
Journal of Manufacturing Processes, 2017Co-Authors: Ali Nassiri, Taeseon Lee, Tim Abke, Brad Kinsey, Shunyi Zhang, Anupam Vivek, Glenn S. DaehnAbstract:Vaporizing Foil Actuator Welding (VFAW) is a solid-state impact welding process where the material is deformed at high strain rates with severe plastic deformation occurring at the interface. Thus, conventional Lagrangian numerical simulation methods are not able to accurately model this process. In this study, two alternative numerical methods, Smoothed Particle Hydrodynamics (SPH) and Arbitrary Lagrangian-Eulerian (ALE), were utilized to investigate parameters that are difficult to measure experimentally, i.e., temperature, pressure, collision velocity, and plastic strain, during CP-Ti/Cu110 impact welding. The other parameters predicted by these two numerical methods such as wavelength and amplitude were used to validate the numerical results versus experimental observations. While both simulation methods can predict the wavy interface pattern created, the vorticities, jetting phenomenon, and molten zone can only be predicted by the SPH method, not the ALE method.
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Vaporizing foil actuator welding as a competing technology to magnetic pulse welding
Journal of Materials Processing Technology, 2016Co-Authors: Marlon Hahn, Glenn S. Daehn, Anupam Vivek, Christian Weddeling, Geoffrey Taber, Erman A TekkayaAbstract:Abstract Photonic Doppler velocimetry was applied to compare magnetic pulse welding and Vaporizing foil actuator welding against each other in the form of lap joints made of 5000 series aluminum alloy sheets under identical experimental conditions which are: charging energies of the pulse generator, specimen geometry, initial distances between flyer and target plate. Impact velocities resulting from rapidly Vaporizing aluminum foils were up to three times higher than those of purely electromagnetically accelerated flyer plates. No magnetic pulse welds were achieved, while every Vaporizing foil experiment yielded a strong weld in that failure always occurred in the joining partners instead of in the weld seam during tensile tests. An analytical model to calculate the transient flyer velocity is presented and compared to the measurements. The average deviation between model and experiment is about 11% with regard to the impact velocity. Hence, the model may be used for the process design of collision welds generated by Vaporizing foil actuators.
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solid state impact welding of bmg and copper by Vaporizing foil actuator welding
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2015Co-Authors: Anupam Vivek, Michael Presley, Katharine M Flores, Nicholas H Hutchinson, Glenn S. DaehnAbstract:Abstract The objective of this study was to create impact welds between a Zr-based Bulk Metallic Glass (BMG) and copper at a laboratory scale and subsequently investigate the relationship between interfacial structure and mechanical properties. Vaporizing Foil Actuator (VFA) has recently been demonstrated as a versatile tool for metalworking applications: impact welding of dissimilar materials being one of them. Its implementation for welding is termed as VFA Welding or VFAW. With 8 kJ input energy into an aluminum foil actuator, a 0.5 mm thick Cu110 alloy sheet was launched toward a BMG target resulting in an impact at a velocity of nearly 600 m/s. For this experiment, the welded interface was straight with a few BMG fragments embedded in the copper sheet in some regions. Hardness tests across the interface showed increase in strength on the copper side. Instrumented peel test resulted in failure in the parent copper sheet. A slower impact velocity during a separate experiment resulted in a weld, which had wavy regions along the interface and in peel failure again happened in the parent copper sheet. Some through-thickness cracks were observed in the BMG plate and there was some spall damage in the copper flyers. TEM electron diffraction on a sample, cut out from the wavy weld interface region using a focused ion beam, showed that devitrification of the BMG was completely avoided in this welding process.
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dynamic compaction of titanium powder by Vaporizing foil actuator assisted shearing
Powder Technology, 2014Co-Authors: Anupam Vivek, John D Defouw, Glenn S. DaehnAbstract:Abstract Electrically driven rapid vaporization of thin metallic foils is known to create very high pressures, which can be harnessed for mechanical work. Recently, Vaporizing foil actuators (VFA) have been applied to a variety of impulse-based metal working operations such as collision welding, embossing, shearing, shape calibration, and closed-die forming. Here, a variation of VFA has been used for dynamic compaction of metallic powders. Holes with a diameter of 10 mm were sheared into Cu110 sheets using foil actuators operating at input electrical energies from 4 kJ to 10 kJ. During the impulse shearing operation, the sheared plugs were found to accelerate up to velocities of 1.4 km/s within a few millimeters of travel distance. These sheared plugs were used as pistons to compress milled commercially pure titanium (CP-Ti) and Ti–6Al–4V alloy (Ti–6–4) powders, both of which had tap densities of approximately 25–28%. Cylindrical green compacts weighing ~ 2 g were produced by this process. The densities of the compacts, measured using the Archimedes principle, were found to increase with input electrical energy. A maximum density of 97% was obtained with CP-Ti powder, while Ti–6–4 powder could be compacted to 93% dense. When compared to a quasistatic cold compaction process, a significant gain in densification with same pressures was observed.
Anupam Vivek - One of the best experts on this subject based on the ideXlab platform.
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Vaporizing foil actuator welding
Mrs Bulletin, 2019Co-Authors: Brian P. Thurston, Anupam Vivek, Bhuvi S.l. Nirudhoddi, Glenn S. DaehnAbstract:Vaporizing foil actuator welding is a form of impact welding, which can be carried out without the use of chemical explosives. Operating at smaller length scales, but with similar driving pressures as explosive welding, Vaporizing foil actuator welding is capable of welding a wide variety of advanced and dissimilar metal combinations. With negligible heating developing during the process, thermal distortion does not occur, and the base-metal properties are retained in the weld. In this article, Vaporizing foil actuator welding of an automotive grade aluminum and steel pair is discussed. A currently functional and complete welding system that can be used for research as well as low volume production is also discussed.
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Numerical investigation of CP-Ti & Cu110 impact welding using smoothed particle hydrodynamics and arbitrary Lagrangian-Eulerian methods
Journal of Manufacturing Processes, 2017Co-Authors: Ali Nassiri, Taeseon Lee, Tim Abke, Brad Kinsey, Shunyi Zhang, Anupam Vivek, Glenn S. DaehnAbstract:Vaporizing Foil Actuator Welding (VFAW) is a solid-state impact welding process where the material is deformed at high strain rates with severe plastic deformation occurring at the interface. Thus, conventional Lagrangian numerical simulation methods are not able to accurately model this process. In this study, two alternative numerical methods, Smoothed Particle Hydrodynamics (SPH) and Arbitrary Lagrangian-Eulerian (ALE), were utilized to investigate parameters that are difficult to measure experimentally, i.e., temperature, pressure, collision velocity, and plastic strain, during CP-Ti/Cu110 impact welding. The other parameters predicted by these two numerical methods such as wavelength and amplitude were used to validate the numerical results versus experimental observations. While both simulation methods can predict the wavy interface pattern created, the vorticities, jetting phenomenon, and molten zone can only be predicted by the SPH method, not the ALE method.
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Vaporizing foil actuator welding as a competing technology to magnetic pulse welding
Journal of Materials Processing Technology, 2016Co-Authors: Marlon Hahn, Glenn S. Daehn, Anupam Vivek, Christian Weddeling, Geoffrey Taber, Erman A TekkayaAbstract:Abstract Photonic Doppler velocimetry was applied to compare magnetic pulse welding and Vaporizing foil actuator welding against each other in the form of lap joints made of 5000 series aluminum alloy sheets under identical experimental conditions which are: charging energies of the pulse generator, specimen geometry, initial distances between flyer and target plate. Impact velocities resulting from rapidly Vaporizing aluminum foils were up to three times higher than those of purely electromagnetically accelerated flyer plates. No magnetic pulse welds were achieved, while every Vaporizing foil experiment yielded a strong weld in that failure always occurred in the joining partners instead of in the weld seam during tensile tests. An analytical model to calculate the transient flyer velocity is presented and compared to the measurements. The average deviation between model and experiment is about 11% with regard to the impact velocity. Hence, the model may be used for the process design of collision welds generated by Vaporizing foil actuators.
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solid state impact welding of bmg and copper by Vaporizing foil actuator welding
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2015Co-Authors: Anupam Vivek, Michael Presley, Katharine M Flores, Nicholas H Hutchinson, Glenn S. DaehnAbstract:Abstract The objective of this study was to create impact welds between a Zr-based Bulk Metallic Glass (BMG) and copper at a laboratory scale and subsequently investigate the relationship between interfacial structure and mechanical properties. Vaporizing Foil Actuator (VFA) has recently been demonstrated as a versatile tool for metalworking applications: impact welding of dissimilar materials being one of them. Its implementation for welding is termed as VFA Welding or VFAW. With 8 kJ input energy into an aluminum foil actuator, a 0.5 mm thick Cu110 alloy sheet was launched toward a BMG target resulting in an impact at a velocity of nearly 600 m/s. For this experiment, the welded interface was straight with a few BMG fragments embedded in the copper sheet in some regions. Hardness tests across the interface showed increase in strength on the copper side. Instrumented peel test resulted in failure in the parent copper sheet. A slower impact velocity during a separate experiment resulted in a weld, which had wavy regions along the interface and in peel failure again happened in the parent copper sheet. Some through-thickness cracks were observed in the BMG plate and there was some spall damage in the copper flyers. TEM electron diffraction on a sample, cut out from the wavy weld interface region using a focused ion beam, showed that devitrification of the BMG was completely avoided in this welding process.
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dynamic compaction of titanium powder by Vaporizing foil actuator assisted shearing
Powder Technology, 2014Co-Authors: Anupam Vivek, John D Defouw, Glenn S. DaehnAbstract:Abstract Electrically driven rapid vaporization of thin metallic foils is known to create very high pressures, which can be harnessed for mechanical work. Recently, Vaporizing foil actuators (VFA) have been applied to a variety of impulse-based metal working operations such as collision welding, embossing, shearing, shape calibration, and closed-die forming. Here, a variation of VFA has been used for dynamic compaction of metallic powders. Holes with a diameter of 10 mm were sheared into Cu110 sheets using foil actuators operating at input electrical energies from 4 kJ to 10 kJ. During the impulse shearing operation, the sheared plugs were found to accelerate up to velocities of 1.4 km/s within a few millimeters of travel distance. These sheared plugs were used as pistons to compress milled commercially pure titanium (CP-Ti) and Ti–6Al–4V alloy (Ti–6–4) powders, both of which had tap densities of approximately 25–28%. Cylindrical green compacts weighing ~ 2 g were produced by this process. The densities of the compacts, measured using the Archimedes principle, were found to increase with input electrical energy. A maximum density of 97% was obtained with CP-Ti powder, while Ti–6–4 powder could be compacted to 93% dense. When compared to a quasistatic cold compaction process, a significant gain in densification with same pressures was observed.
Eberhard Gill - One of the best experts on this subject based on the ideXlab platform.
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A Comprehensive Model for Control of Vaporizing Liquid Microthrusters
IEEE Transactions on Control Systems Technology, 2019Co-Authors: Marsil A C Silva, Dadui C Guerrieri, Angelo Cervone, Stefano Silvestrini, Eberhard GillAbstract:This brief presents a comprehensive approach for the modeling of micropropulsion systems based on the vaporization of a liquid. The model combines the analytical and empirical relations derived from extensive experimental analysis and fundamental physical laws. This allows modeling of key parameters, such as mass flow rate, for the entire system comprising a tank to store the liquid propellant, a valve to control the mass flow, and a microthruster that vaporizes the propellant and accelerates it generating thrust. The model is evaluated by a sensitivity analysis considering the boundaries of the modeling space, and it has been tested in a simulation loop demonstrating the attitude control of a nanosatellite using a set of four thrusters. The results of the simulation are used to test the developed model.
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Vaporizing liquid microthrusters with integrated heaters and temperature measurement
Sensors and Actuators A-physical, 2017Co-Authors: Marsil A C Silva, Dadui C Guerrieri, Henk Van Zeijl, Angelo Cervone, Eberhard GillAbstract:This paper presents the results of design, manufacturing and characterization of Vaporizing Liquid Microthrusters (VLM) with integrated molybdenum heaters and temperature sensing. The thrusters use water as the propellant and are designed for use in CubeSats and PocketQubes. The devices are manufactured using silicon based MEMS (Micro Electro Mechanical Systems) technology and include resistive heaters to vaporize the propellant. The measurements of the heaters’ resistances are used to estimate the temperature in the Vaporizing chamber. The manufacturing process is described as well as the characterization of the thrusters’ structural and electrical elements. In total 12 devices with different combinations of heaters and nozzles have been assessed and four of them have been used to demonstrate the successful operation of the thrusters. Results are used to validate the thrusters and show a performance close to the design parameters and comparable to other devices found in the literature.
Marsil A C Silva - One of the best experts on this subject based on the ideXlab platform.
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A Comprehensive Model for Control of Vaporizing Liquid Microthrusters
IEEE Transactions on Control Systems Technology, 2019Co-Authors: Marsil A C Silva, Dadui C Guerrieri, Angelo Cervone, Stefano Silvestrini, Eberhard GillAbstract:This brief presents a comprehensive approach for the modeling of micropropulsion systems based on the vaporization of a liquid. The model combines the analytical and empirical relations derived from extensive experimental analysis and fundamental physical laws. This allows modeling of key parameters, such as mass flow rate, for the entire system comprising a tank to store the liquid propellant, a valve to control the mass flow, and a microthruster that vaporizes the propellant and accelerates it generating thrust. The model is evaluated by a sensitivity analysis considering the boundaries of the modeling space, and it has been tested in a simulation loop demonstrating the attitude control of a nanosatellite using a set of four thrusters. The results of the simulation are used to test the developed model.
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Vaporizing liquid microthrusters with integrated heaters and temperature measurement
Sensors and Actuators A-physical, 2017Co-Authors: Marsil A C Silva, Dadui C Guerrieri, Henk Van Zeijl, Angelo Cervone, Eberhard GillAbstract:This paper presents the results of design, manufacturing and characterization of Vaporizing Liquid Microthrusters (VLM) with integrated molybdenum heaters and temperature sensing. The thrusters use water as the propellant and are designed for use in CubeSats and PocketQubes. The devices are manufactured using silicon based MEMS (Micro Electro Mechanical Systems) technology and include resistive heaters to vaporize the propellant. The measurements of the heaters’ resistances are used to estimate the temperature in the Vaporizing chamber. The manufacturing process is described as well as the characterization of the thrusters’ structural and electrical elements. In total 12 devices with different combinations of heaters and nozzles have been assessed and four of them have been used to demonstrate the successful operation of the thrusters. Results are used to validate the thrusters and show a performance close to the design parameters and comparable to other devices found in the literature.
Angelo Cervone - One of the best experts on this subject based on the ideXlab platform.
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A Comprehensive Model for Control of Vaporizing Liquid Microthrusters
IEEE Transactions on Control Systems Technology, 2019Co-Authors: Marsil A C Silva, Dadui C Guerrieri, Angelo Cervone, Stefano Silvestrini, Eberhard GillAbstract:This brief presents a comprehensive approach for the modeling of micropropulsion systems based on the vaporization of a liquid. The model combines the analytical and empirical relations derived from extensive experimental analysis and fundamental physical laws. This allows modeling of key parameters, such as mass flow rate, for the entire system comprising a tank to store the liquid propellant, a valve to control the mass flow, and a microthruster that vaporizes the propellant and accelerates it generating thrust. The model is evaluated by a sensitivity analysis considering the boundaries of the modeling space, and it has been tested in a simulation loop demonstrating the attitude control of a nanosatellite using a set of four thrusters. The results of the simulation are used to test the developed model.
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Vaporizing liquid microthrusters with integrated heaters and temperature measurement
Sensors and Actuators A-physical, 2017Co-Authors: Marsil A C Silva, Dadui C Guerrieri, Henk Van Zeijl, Angelo Cervone, Eberhard GillAbstract:This paper presents the results of design, manufacturing and characterization of Vaporizing Liquid Microthrusters (VLM) with integrated molybdenum heaters and temperature sensing. The thrusters use water as the propellant and are designed for use in CubeSats and PocketQubes. The devices are manufactured using silicon based MEMS (Micro Electro Mechanical Systems) technology and include resistive heaters to vaporize the propellant. The measurements of the heaters’ resistances are used to estimate the temperature in the Vaporizing chamber. The manufacturing process is described as well as the characterization of the thrusters’ structural and electrical elements. In total 12 devices with different combinations of heaters and nozzles have been assessed and four of them have been used to demonstrate the successful operation of the thrusters. Results are used to validate the thrusters and show a performance close to the design parameters and comparable to other devices found in the literature.
