Grain size and formation of the Peripheral Coarse Grain(PCG)defect influence the mechanical and crash properties of extruded profiles.Controlling microstructural evolution during the extrusion of 6XXX series aluminum ...Grain size and formation of the Peripheral Coarse Grain(PCG)defect influence the mechanical and crash properties of extruded profiles.Controlling microstructural evolution during the extrusion of 6XXX series aluminum alloys is therefore essential to ensure the performance of structural components.In this work,three profiles with the same nominal geometry were extruded with a die comprising three different bearing geometries to create different extrusion conditions.Each profile was analyzed experimentally to gather data on the microstructure and mechanical properties.Bulge testing revealed that Profile 2,with the thickest PCG layer(490-1150µm),exhibited worse mechanical performance,with a hoop strain at fracture of 0.08 and a peak load of 51.5 kN,compared to Profiles 1 and 3,which had higher hoop strains(0.13 and 0.14)and peak loads(56.1 and 57.6 kN,respectively).Finite Element Method(FEM)simulations of the extrusion process were carried out using Qform Extrusion UK with a post-processing subroutine developed and implemented to calculate additional parameters such as the stored energy,percentage dynamic recrystallization,grain size,and PCG formation based on standard output parameters from the simulation including strain,temperature and strain rate.The simulation demonstrated that the highest strain rate(40-220 s^(-1))and stored energy(150,000-440,000 J m^(-3))in Profile 2 led to the thickest PCG layer.Based on these results,the proposed predictive model was validated against experimental data,demonstrating high accuracy in predicting PCG thickness and grain size while effectively capturing the influence of process parameters on microstructural evolution.展开更多
A customized combined methodology based on both 2D CFD （computational fluid dynamics） and lumped parameters numerical modeling, useful for simulating the hydraulic behavior of orbit annular machines, has been develo...A customized combined methodology based on both 2D CFD （computational fluid dynamics） and lumped parameters numerical modeling, useful for simulating the hydraulic behavior of orbit annular machines, has been developed and here presented. More in details, the predictive capabilities of this CAE （computer-aided engineering） tool can be applied for the study of both roller and gerotor architectures and considering both pumping and motoring operating mode. First of all, an in-house developed 2D CFD methodology, based on the integration of the stationary form of the Reynolds equation for the determination of the pressure distribution inside the lateral clearances bounded by the sides of the stator-rotor group and the valve plate, as well as the internal manifold surface, is firstly presented and applied. The same computational procedure has been also involved for the investigation of the leakages through the clearance between the valve plate and the balancing ring. After that, a lumped and distributed parameters numerical model has been involved for the simulation of a typical orbit roller motor operation. In this case, particular care has been devoted to the modeling of the axial leakage clearances, adopting analytical interpolation functions deducted from the numerical results calculated applying the previously described 2D CFD methodology. Finally, the whole CAE approach has been validated by means of a comprehensive numerical versus experimental comparison, obtaining a general good accordance for the overall operating field of this particular type of hydraulic unit.展开更多
Solar flares, intense bursts of radiation, can disrupt the atmosphere and potentially affect communication, navigation and electrical systems. A newly developed miniaturised microwave radiometer used on a space-borne ...Solar flares, intense bursts of radiation, can disrupt the atmosphere and potentially affect communication, navigation and electrical systems. A newly developed miniaturised microwave radiometer used on a space-borne platform should offer astronomers unprecedented understanding of the largest explosive phenomena in our solar system. In this paper the activity and results of the EU funded research project FLARES are presented. Objective of FLARES has been the study, analysis and design of millimetre-wave system-on-chip (SoC) radiometers for space-borne detection of solar flares. Thanks to the proposed methodology, the power consumption and encumbrance (volume, weight) of the instrument can be sensibly reduced when compared to the devices currently in operation for observing and studying solar flares. In particular, the proposed SoC Dicke radiometer can achieve a ten-time better resolution. This in turn, allows detecting solar flares having relatively low intensity, about 100 times lower when compared to the flares currently detected by the existing systems, owing to space-borne operations and the microchip-level miniaturization through silicon technology under space qualification.展开更多
Vertical GaN power MOSFET is a novel technology that offers great potential for power switching applications.Being still in an early development phase,vertical GaN devices are yet to be fully optimized and require car...Vertical GaN power MOSFET is a novel technology that offers great potential for power switching applications.Being still in an early development phase,vertical GaN devices are yet to be fully optimized and require careful studies to foster their development.In this work,we report on the physical insights into device performance improvements obtained during the development of vertical GaN-on-Si trench MOSFETs(TMOS’s)provided by TCAD simulations,enhancing the dependability of the adopted process optimization approaches.Specifically,two different TMOS devices are compared in terms of transfer-curve hysteresis(H)and subthreshold slope(SS),showing a≈75%H reduction along with a≈30%SS decrease.Simulations allow attributing the achieved improvements to a decrease in the border and interface traps,respectively.A sensitivity analysis is also carried out,allowing to quantify the additional trap density reduction required to minimize both figures of merit.展开更多
An innovative approach was introduced for the development of a AA6063 recrystallization model.This method incorporated a regression-based technique for the determination of material constants and introduced novel equa...An innovative approach was introduced for the development of a AA6063 recrystallization model.This method incorporated a regression-based technique for the determination of material constants and introduced novel equations for assessing the grain size evolution.Calibration and validation of this methodology involved a combination of experimentally acquired microstructural data from the extrusion of three different AA6063 profiles and results from the simulation using the Qform Extrusion UK finite element code.The outcomes proved the agreement between experimental findings and numerical prediction of the microstructural evolution.The trend of the grain size variation based on different process parameters was accurately simulated,both after dynamic and static recrystallization,with an error of less than 25% in almost the whole sampling computations.展开更多
The paper analyzes the dynamic behaviour of an industrial system devoted to the automated hydraulic packaging of beverages. More in detail, a lumped and distributed numerical approach is used to model both the filling...The paper analyzes the dynamic behaviour of an industrial system devoted to the automated hydraulic packaging of beverages. More in detail, a lumped and distributed numerical approach is used to model both the filling system and the multi-actuators hydraulic circuit needed to shape and separate the packages. The model reliability and accuracy are addressed by means of a numerical vs. experimental comparison of the main hydraulic and mechanical quantities for an actual production rate. Afterwards, the system architecture is redesigned in order to obtain higher production rates, and the effects of the hydraulic behaviour variation on the hydraulic efficiency are highlighted. Finally, a sensitivity analysis with respect to the main design parameters is carried out, in order to determine the circuit layout that maximizes the system efficiency in the whole production-rate range.展开更多
The paper deals with the simulation and the experimental verification of the hydraulic behavior of an electro-hydraulic load-sensing proportional control valve. An innovative CAE （computer aided engineering） methodo...The paper deals with the simulation and the experimental verification of the hydraulic behavior of an electro-hydraulic load-sensing proportional control valve. An innovative CAE （computer aided engineering） methodology, developed combining CFD （computational fluid dynamics） simulations with lumped and distributed numerical modeling, is firstly introduced and tailored by comparing the numerical results with measurements coming from an experimental campaign performed for a wide range of pressure loads and metered flow rates. Then, both the reliability and the limits of the numerical approach are highlighted through a detailed numerical vs. experimental comparison, involving the pressure of the main hydraulic lines, the flow rate through the first section and the local compensator displacement. Finally, the CAE methodology has been applied for assessing the internal ducts hydraulic permeability and the local compensator spring pre-load influence on the control valve metering curves. At the end of this analysis, an optimized design configuration, featuring a maximum controlled volumetric flow rate increased of more than 25%, has been proposed.展开更多
基金supported by the European Union’s Horizon Europe research and innovation programme,Zero Emission electric Vehicles enabled by haRmonised circularity,under No.101138034.
文摘Grain size and formation of the Peripheral Coarse Grain(PCG)defect influence the mechanical and crash properties of extruded profiles.Controlling microstructural evolution during the extrusion of 6XXX series aluminum alloys is therefore essential to ensure the performance of structural components.In this work,three profiles with the same nominal geometry were extruded with a die comprising three different bearing geometries to create different extrusion conditions.Each profile was analyzed experimentally to gather data on the microstructure and mechanical properties.Bulge testing revealed that Profile 2,with the thickest PCG layer(490-1150µm),exhibited worse mechanical performance,with a hoop strain at fracture of 0.08 and a peak load of 51.5 kN,compared to Profiles 1 and 3,which had higher hoop strains(0.13 and 0.14)and peak loads(56.1 and 57.6 kN,respectively).Finite Element Method(FEM)simulations of the extrusion process were carried out using Qform Extrusion UK with a post-processing subroutine developed and implemented to calculate additional parameters such as the stored energy,percentage dynamic recrystallization,grain size,and PCG formation based on standard output parameters from the simulation including strain,temperature and strain rate.The simulation demonstrated that the highest strain rate(40-220 s^(-1))and stored energy(150,000-440,000 J m^(-3))in Profile 2 led to the thickest PCG layer.Based on these results,the proposed predictive model was validated against experimental data,demonstrating high accuracy in predicting PCG thickness and grain size while effectively capturing the influence of process parameters on microstructural evolution.
文摘A customized combined methodology based on both 2D CFD （computational fluid dynamics） and lumped parameters numerical modeling, useful for simulating the hydraulic behavior of orbit annular machines, has been developed and here presented. More in details, the predictive capabilities of this CAE （computer-aided engineering） tool can be applied for the study of both roller and gerotor architectures and considering both pumping and motoring operating mode. First of all, an in-house developed 2D CFD methodology, based on the integration of the stationary form of the Reynolds equation for the determination of the pressure distribution inside the lateral clearances bounded by the sides of the stator-rotor group and the valve plate, as well as the internal manifold surface, is firstly presented and applied. The same computational procedure has been also involved for the investigation of the leakages through the clearance between the valve plate and the balancing ring. After that, a lumped and distributed parameters numerical model has been involved for the simulation of a typical orbit roller motor operation. In this case, particular care has been devoted to the modeling of the axial leakage clearances, adopting analytical interpolation functions deducted from the numerical results calculated applying the previously described 2D CFD methodology. Finally, the whole CAE approach has been validated by means of a comprehensive numerical versus experimental comparison, obtaining a general good accordance for the overall operating field of this particular type of hydraulic unit.
文摘Solar flares, intense bursts of radiation, can disrupt the atmosphere and potentially affect communication, navigation and electrical systems. A newly developed miniaturised microwave radiometer used on a space-borne platform should offer astronomers unprecedented understanding of the largest explosive phenomena in our solar system. In this paper the activity and results of the EU funded research project FLARES are presented. Objective of FLARES has been the study, analysis and design of millimetre-wave system-on-chip (SoC) radiometers for space-borne detection of solar flares. Thanks to the proposed methodology, the power consumption and encumbrance (volume, weight) of the instrument can be sensibly reduced when compared to the devices currently in operation for observing and studying solar flares. In particular, the proposed SoC Dicke radiometer can achieve a ten-time better resolution. This in turn, allows detecting solar flares having relatively low intensity, about 100 times lower when compared to the flares currently detected by the existing systems, owing to space-borne operations and the microchip-level miniaturization through silicon technology under space qualification.
基金funding from the Electronic Component Systems for European Leadership Joint Undertaking (ECSEL JU),under grant agreement No.101007229support from the European Union’s Horizon 2020 Research and Innovation Programme,Germany,France,Belgium,Austria,Sweden,Spain,and Italy
文摘Vertical GaN power MOSFET is a novel technology that offers great potential for power switching applications.Being still in an early development phase,vertical GaN devices are yet to be fully optimized and require careful studies to foster their development.In this work,we report on the physical insights into device performance improvements obtained during the development of vertical GaN-on-Si trench MOSFETs(TMOS’s)provided by TCAD simulations,enhancing the dependability of the adopted process optimization approaches.Specifically,two different TMOS devices are compared in terms of transfer-curve hysteresis(H)and subthreshold slope(SS),showing a≈75%H reduction along with a≈30%SS decrease.Simulations allow attributing the achieved improvements to a decrease in the border and interface traps,respectively.A sensitivity analysis is also carried out,allowing to quantify the additional trap density reduction required to minimize both figures of merit.
文摘An innovative approach was introduced for the development of a AA6063 recrystallization model.This method incorporated a regression-based technique for the determination of material constants and introduced novel equations for assessing the grain size evolution.Calibration and validation of this methodology involved a combination of experimentally acquired microstructural data from the extrusion of three different AA6063 profiles and results from the simulation using the Qform Extrusion UK finite element code.The outcomes proved the agreement between experimental findings and numerical prediction of the microstructural evolution.The trend of the grain size variation based on different process parameters was accurately simulated,both after dynamic and static recrystallization,with an error of less than 25% in almost the whole sampling computations.
文摘The paper analyzes the dynamic behaviour of an industrial system devoted to the automated hydraulic packaging of beverages. More in detail, a lumped and distributed numerical approach is used to model both the filling system and the multi-actuators hydraulic circuit needed to shape and separate the packages. The model reliability and accuracy are addressed by means of a numerical vs. experimental comparison of the main hydraulic and mechanical quantities for an actual production rate. Afterwards, the system architecture is redesigned in order to obtain higher production rates, and the effects of the hydraulic behaviour variation on the hydraulic efficiency are highlighted. Finally, a sensitivity analysis with respect to the main design parameters is carried out, in order to determine the circuit layout that maximizes the system efficiency in the whole production-rate range.
文摘The paper deals with the simulation and the experimental verification of the hydraulic behavior of an electro-hydraulic load-sensing proportional control valve. An innovative CAE （computer aided engineering） methodology, developed combining CFD （computational fluid dynamics） simulations with lumped and distributed numerical modeling, is firstly introduced and tailored by comparing the numerical results with measurements coming from an experimental campaign performed for a wide range of pressure loads and metered flow rates. Then, both the reliability and the limits of the numerical approach are highlighted through a detailed numerical vs. experimental comparison, involving the pressure of the main hydraulic lines, the flow rate through the first section and the local compensator displacement. Finally, the CAE methodology has been applied for assessing the internal ducts hydraulic permeability and the local compensator spring pre-load influence on the control valve metering curves. At the end of this analysis, an optimized design configuration, featuring a maximum controlled volumetric flow rate increased of more than 25%, has been proposed.
