In a full-arch implant rehabilitation ad modum Branemark, the distribution of stress and strain in mandibular bone is influenced by the type, number and position of implants used. In particular, the biomechanical beha...In a full-arch implant rehabilitation ad modum Branemark, the distribution of stress and strain in mandibular bone is influenced by the type, number and position of implants used. In particular, the biomechanical behaviour of the bone structure after complete osseointegration depends on the load transferred to the bone by each fixture. In this study, a finite-element analysis of two models was performed. Models of an all-on-four configuration and a six-implant configuration were compared in a worst-case scenario. A new V parameter is presented to aid the quantitative and comparative analysis of the all-on-four and six-implant configurations. The influence of orthotropy was also investigated, and a geometric change in the all-on-four configuration is presented.展开更多
Background:The reverse obliquity inter-trochanteric fracture is a distinct fracture pattern that is mechanically different from most inter-trochanteric fractures and the optional treatment of it is still controversial...Background:The reverse obliquity inter-trochanteric fracture is a distinct fracture pattern that is mechanically different from most inter-trochanteric fractures and the optional treatment of it is still controversial.The purpose of this study was to compare differences in the efficacy of a novel nail(medial support nail[MSN-II])and proximal femoral nail anti-rotation(PFNA-II)in the treatment of reverse obliquity inter-trochanteric fractures(Arbeitsgemeinschaft fur Osteosynthesfrogen/Orthopedic Trauma Association[AO/OTA]31-A3.1)using finite-element analysis.Methods:Modeling software was used to establish a three-dimensional model of MSN-II and PFNA-II and an A3.1 inter-trochanteric fracture model.Abaqus software was used to implement different force loads to compare finite-element biomechanical parameters such as the maximum stress in implant and the displacement of fracture site.Results:The femoral stress,implant stress and fracture site displacement of MSN-II was less than that of PFNA-II.The results indicated that the maximal femoral stress was 581 MPa for PFNA-II and 443 MPa for the MSN-II.The maximum stress values in the PFNA-II and MSN-II models were 291 and 241 MPa,respectively.The maximal displacements of the fracture site were 1.47 and 1.16 mm in the PFNA-II and MSN-II models,respectively.Conclusions:Compared with PFNA-II for inter-trochanteric fracture(AO/OTA 31-A3.1),MSN-II which was designed with a triangular stability structure can provide better biomechanical stability.The MSN-II may be a feasible option for the treatment of reverse obliquity inter-trochanteric fracture.展开更多
Regarding quality inspection of technologically important nanocomposite hard coatings based on Ti,B,Si,C,and N and bioceramics such as hydroxyapatite that are used in small-scale high-precision devices and bio-implant...Regarding quality inspection of technologically important nanocomposite hard coatings based on Ti,B,Si,C,and N and bioceramics such as hydroxyapatite that are used in small-scale high-precision devices and bio-implants,it is essential to study the failure mechanisms associated with nanoindentation,such as fracture,delamination,and chipping.The stress imposed by the indenter can affect the fracture morphology and the interfacial fracture energy,depending on indenter shape,substrate type,crystallographic properties,pre-existing flaws,internal microcracks,and pre-strain.Reported here are finite-element-based fracture studies that provide insights into the different cracking mechanisms related to the aforementioned failure process,showing that the fracture morphology is affected by the interaction of different cracking events.The interfacial fracture energy,toughness,and residual stress are calculated using existing models with minor adjustments,and it is found that increasing the indenter sharpness improves the shear stress distribution,making the coating more prone to separation.Depending on the prevailing type of stress,the stress distribution beneath the depression results in either crack formation or a dislocation pile-up leading to strain hardening.Different forms of resistances resulting from the indentation process are found to affect the tip–sample conduction,and because of its stronger induced plasticity than that of a Berkovich indenter tip,a sharper cube-corner tip produces more resistance.展开更多
The horizontal bearing behavior of a single batter pile(SBP)is vital to its application in practical engineering;however,the horizontal responses of SBPs change with the directions of horizontal loads,and this phenome...The horizontal bearing behavior of a single batter pile(SBP)is vital to its application in practical engineering;however,the horizontal responses of SBPs change with the directions of horizontal loads,and this phenomenon is rarely investigated.Therefore,the directional differences in the horizontal bearing behaviors of SBPs are investigated in this study.Four model tests are conducted to preliminarily examine the effects of the skew angle of horizontal loads on the horizontal bearing capacities and distributions of the bending moments of the SBPs.Subsequently,the differences in the responses of the SBPs under horizontal loads in various directions at full scale are analyzed comprehensively via finite-element(FE)analysis.The effects of the skew angle on SBP-soil interaction are discussed.Moreover,an empirical design method is proposed based on the FE analysis results to predict the bearing ratios of SBPs in medium-dense and dense sand while considering the effects of the skew angle,batter angle,and pile diameter.The method is confirmed to be effective,as confirmed by the close agreement between the predicting results with the model test(reported in this study)and centrifuge model test results(reported in the literature).展开更多
As members of doubly salient magnetless linear machines,linear variable flux reluctance(LVFR)and wound field flux reversal(LWFFR)machines inherit the merits of conventional magnetless linear machines such as low cost,...As members of doubly salient magnetless linear machines,linear variable flux reluctance(LVFR)and wound field flux reversal(LWFFR)machines inherit the merits of conventional magnetless linear machines such as low cost,high flux adjustment capability and high reliability.Furthermore,like linear switched reluctance machine,they have a very simple and compact long secondary,which are very attractive for long stroke applications.However,low force capability is their major defect.To solve this issue,new LVFR and LWFFR machine topologies were proposed in recent work,while lacking studies on their force improvement mechanism and further force evaluation.In this paper,LVFR and LWFFR machines with improved force performance are comparatively studied with the emphasis on their force capabilities.The operation principle of the two machines is analyzed based on magnetic field harmonics produced by flux modulation.Contributions of air-gap flux density harmonic components to no-load back electromagnetic forces of the two machines are analyzed and the average force equation is derived.Moreover,force capabilities of the both machines are investigated by means of the time-stepping finite-element analysis to verify the theoretical analysis.展开更多
Metamaterials have been receiving an increasing amount of interest in recent years. As a type of metamaterial, pentamode materials (PMs) approximate the elastic properties of liquids. In this study, a finite-element a...Metamaterials have been receiving an increasing amount of interest in recent years. As a type of metamaterial, pentamode materials (PMs) approximate the elastic properties of liquids. In this study, a finite-element analysis was conducted to predict the mechanical properties of PM structures by altering the thin wall thicknesses and layer numbers to obtain an outstanding load-bearing capacity. It was found that as the thin wall thickness increased from 0.15 to 0.45 mm, the compressive modulus of the PM structures increased and the Poisson’s ratio decreased. As the layer number increased, the Poisson’s ratio of the PM structures increased rapidly and reaches a stable value ranging from 0.50 to 0.55. Simulation results of the stress distribution in the PM structures confirmed that stress concentrations exist at the junctions of the thin walls and weights. For validation, Ti–6Al–4V specimens were fabricated by selective laser melting (SLM), and the mechanical properties of these specimens (i.e., Poisson’s ratio and elastic modulus) were experimentally studied. Good consistency was achieved between the numerical and experimental results. This work is beneficial for the design and development of PM structures with simultaneous load-bearing capacity and pentamodal properties.展开更多
Interdigitated transducers(IDTs)were originally designed as delay lines for radars.Half a century later,they have found new life as actuators for microfluidic systems.By generating strong acoustic fields,they trigger ...Interdigitated transducers(IDTs)were originally designed as delay lines for radars.Half a century later,they have found new life as actuators for microfluidic systems.By generating strong acoustic fields,they trigger nonlinear effects that enable pumping and mixing of fluids,and moving particles without contact.However,the transition from signal processing to actuators comes with a range of challenges concerning power density and spatial resolution that have spurred exciting developments in solid-state acoustics and especially in IDT design.Assuming some familiarity with acoustofluidics,this paper aims to provide a tutorial for IDT design and characterization for the purpose of acoustofluidic actuation.It is targeted at a diverse audience of researchers in various fields,including fluid mechanics,acoustics,and microelectronics.展开更多
The output performance of a 980-nm broad-area vertical-cavity surface-emitting laser(VCSEL) is improved by optimizing the p-electrode diameter in this study.Based on a three-dimensional finite-element method,the curre...The output performance of a 980-nm broad-area vertical-cavity surface-emitting laser(VCSEL) is improved by optimizing the p-electrode diameter in this study.Based on a three-dimensional finite-element method,the current density distribution within the active region of the VCSEL is optimized through the appropriate adjustment of the p-electrode diameter,and uniform current-density distribution is achieved.Then,the effects of this optimization are studied experimentally.The L-I-V characteristics under different temperatures of the VCSELs with different p-electrode diameters are investigated,and better temperature stability is demonstrated in the VCSEL with an optimized p-electrode diameter.The far-field measurements show that with an injected current of 2 A,the far-field divergence angle of the VCSEL with an optimized p-electrode diameter is 9°,which is much lower than the far-field angle of the VCSEL without this optimization.Also the VCSEL with an optimized p-electrode diameter shows a better near-field distribution.展开更多
Due to their excellent efficiency,power density and constant power speed region,interior permanent-magnet(IPM)machines are very suitable for electric vehicles(EVs).This paper proposed a new IPM rotor topology,which ca...Due to their excellent efficiency,power density and constant power speed region,interior permanent-magnet(IPM)machines are very suitable for electric vehicles(EVs).This paper proposed a new IPM rotor topology,which can offer high reluctance torque,wide constant power speed range and excellent overload capability.Besides,five rotor topologies with integral-slot distributed-windings IPM machines,including four existing IPM topologies and the proposed IPM topology,are designed optimally.Their characteristics,which include d-q axis inductances,saliency ratios,electromagnetic torques,corresponding torque ripples,back-electromotive forces(EMFs),overload capabilities and flux weakening performances are evaluated quantitatively.Finally,a three phase 48s8p hybrid rotor PM machine is built to verify the performances of the proposed IPM machine.This work provides some general concepts for machine developers who are willing to build IPM machines for high-performance EV applications.展开更多
A novel anchorage for long-span suspension bridges,called pile-caisson composite structures,was recently proposed by the authors in an attempt to reduce the construction period and costs.This study aims to investigate...A novel anchorage for long-span suspension bridges,called pile-caisson composite structures,was recently proposed by the authors in an attempt to reduce the construction period and costs.This study aims to investigate the displacement and force behavior of piles in a pile-caisson composite structure under eccentric inclined loading considering different stratum features.To this end,both 1g model tests and three-dimensional numerical simulations were performed.Two groups of 1g model tests were used to validate the finite-element(FE)method.Parametric studies were then performed to investigate the effects of groundwater level,burial depth of the pile-caisson composite structure,and distribution of soil layers on the performance of the pile-caisson composite structure.The numerical analyses indicated that the influence of the groundwater level on the stability of the caisson was much greater than that of the piles.In addition,increasing the burial depth of the pile-caisson composite structure can assist in reducing the displacements and improving the stability of the pile-caisson composite structure.In addition,the distribution of soil layers can significantly affect the stability of the pile-caisson composite structure,especially the soil layer around the caisson.展开更多
Jet grouting slabs are widely used in deep excavations owing to their effectiveness for reducing the deflection of the diaphragm wall and the prop forces acting on the struts and improving the basal-heave stability.In...Jet grouting slabs are widely used in deep excavations owing to their effectiveness for reducing the deflection of the diaphragm wall and the prop forces acting on the struts and improving the basal-heave stability.In this paper,according to case histories in Singapore,a series of finite-element numerical simulations are performed to evaluate the effects of jet grouting slabs on responses to deep braced excavations.On the basis of a parametric sensitivity study,a reasonable thickness of jet grouting slabs is proposed.The effects of the wall depth,wall stiffness,soft-clay thickness,and stiffness on the performance of the jet grouting slabs are assessed by comparing and analyzing a series of simulation results.It is found that the soft-clay thickness significantly affects the wall deflection and basal heave in deep excavation.During the design of support structures,soil profiles should be considered first.The findings of this study provide a reference and guidance for the support system design of similar projects.展开更多
In this study,several types of linear actuators that adopt different permanent-magnet(PM)topologies are studied and compared.These linear actuators are based on the concept of PM magnetic screw transmission,which offe...In this study,several types of linear actuators that adopt different permanent-magnet(PM)topologies are studied and compared.These linear actuators are based on the concept of PM magnetic screw transmission,which offers high force density,high reliability,and overload protection.Using different magnetic configurations and assembly methods,these linear actuators are designed and optimized for a fair comparison.Initially,based on the operating principle and maximum thrust force,the surface-mounted magnetic screw is described and optimized.Furthermore,the embedded magnetic screw,Halbach array magnetic screw,and field modulated magnetic screw are investigated and compared.Their electromagnetic performances,such as thrust force,torque,magnetic losses,and demagnetization effects are analytically assessed and verified using finite-element analysis.Finally,a prototype of the surface-mounted magnetic screw is developed to validate the predictions.展开更多
文摘In a full-arch implant rehabilitation ad modum Branemark, the distribution of stress and strain in mandibular bone is influenced by the type, number and position of implants used. In particular, the biomechanical behaviour of the bone structure after complete osseointegration depends on the load transferred to the bone by each fixture. In this study, a finite-element analysis of two models was performed. Models of an all-on-four configuration and a six-implant configuration were compared in a worst-case scenario. A new V parameter is presented to aid the quantitative and comparative analysis of the all-on-four and six-implant configurations. The influence of orthotropy was also investigated, and a geometric change in the all-on-four configuration is presented.
基金This work was supported by a grant from the Capital Health Research and Development of Special Grants(No.2016-1-5012)。
文摘Background:The reverse obliquity inter-trochanteric fracture is a distinct fracture pattern that is mechanically different from most inter-trochanteric fractures and the optional treatment of it is still controversial.The purpose of this study was to compare differences in the efficacy of a novel nail(medial support nail[MSN-II])and proximal femoral nail anti-rotation(PFNA-II)in the treatment of reverse obliquity inter-trochanteric fractures(Arbeitsgemeinschaft fur Osteosynthesfrogen/Orthopedic Trauma Association[AO/OTA]31-A3.1)using finite-element analysis.Methods:Modeling software was used to establish a three-dimensional model of MSN-II and PFNA-II and an A3.1 inter-trochanteric fracture model.Abaqus software was used to implement different force loads to compare finite-element biomechanical parameters such as the maximum stress in implant and the displacement of fracture site.Results:The femoral stress,implant stress and fracture site displacement of MSN-II was less than that of PFNA-II.The results indicated that the maximal femoral stress was 581 MPa for PFNA-II and 443 MPa for the MSN-II.The maximum stress values in the PFNA-II and MSN-II models were 291 and 241 MPa,respectively.The maximal displacements of the fracture site were 1.47 and 1.16 mm in the PFNA-II and MSN-II models,respectively.Conclusions:Compared with PFNA-II for inter-trochanteric fracture(AO/OTA 31-A3.1),MSN-II which was designed with a triangular stability structure can provide better biomechanical stability.The MSN-II may be a feasible option for the treatment of reverse obliquity inter-trochanteric fracture.
文摘Regarding quality inspection of technologically important nanocomposite hard coatings based on Ti,B,Si,C,and N and bioceramics such as hydroxyapatite that are used in small-scale high-precision devices and bio-implants,it is essential to study the failure mechanisms associated with nanoindentation,such as fracture,delamination,and chipping.The stress imposed by the indenter can affect the fracture morphology and the interfacial fracture energy,depending on indenter shape,substrate type,crystallographic properties,pre-existing flaws,internal microcracks,and pre-strain.Reported here are finite-element-based fracture studies that provide insights into the different cracking mechanisms related to the aforementioned failure process,showing that the fracture morphology is affected by the interaction of different cracking events.The interfacial fracture energy,toughness,and residual stress are calculated using existing models with minor adjustments,and it is found that increasing the indenter sharpness improves the shear stress distribution,making the coating more prone to separation.Depending on the prevailing type of stress,the stress distribution beneath the depression results in either crack formation or a dislocation pile-up leading to strain hardening.Different forms of resistances resulting from the indentation process are found to affect the tip–sample conduction,and because of its stronger induced plasticity than that of a Berkovich indenter tip,a sharper cube-corner tip produces more resistance.
基金supported by the National Natural Science Foundation of China(Grant Nos.52178358,52108349,and 51779217)the Key Project of the Natural Science Foundation of Zhejiang Province(No.LXZ22E080001).
文摘The horizontal bearing behavior of a single batter pile(SBP)is vital to its application in practical engineering;however,the horizontal responses of SBPs change with the directions of horizontal loads,and this phenomenon is rarely investigated.Therefore,the directional differences in the horizontal bearing behaviors of SBPs are investigated in this study.Four model tests are conducted to preliminarily examine the effects of the skew angle of horizontal loads on the horizontal bearing capacities and distributions of the bending moments of the SBPs.Subsequently,the differences in the responses of the SBPs under horizontal loads in various directions at full scale are analyzed comprehensively via finite-element(FE)analysis.The effects of the skew angle on SBP-soil interaction are discussed.Moreover,an empirical design method is proposed based on the FE analysis results to predict the bearing ratios of SBPs in medium-dense and dense sand while considering the effects of the skew angle,batter angle,and pile diameter.The method is confirmed to be effective,as confirmed by the close agreement between the predicting results with the model test(reported in this study)and centrifuge model test results(reported in the literature).
基金supported in part by the National Natural Science Foundation of China under Grant 51977099 and Grant 52177044in part by the Hong Kong Scholars Program under Grant XJ2019031+2 种基金in part by the China Postdoctoral Science Foundation under Grant 2019T120395in part by the Natural Science Foundation of Jiangsu Higher Education Institutions under Grant 21KJA470004in part by the Priority Academic Program Development of Jiangsu Higher Education Institutions.
文摘As members of doubly salient magnetless linear machines,linear variable flux reluctance(LVFR)and wound field flux reversal(LWFFR)machines inherit the merits of conventional magnetless linear machines such as low cost,high flux adjustment capability and high reliability.Furthermore,like linear switched reluctance machine,they have a very simple and compact long secondary,which are very attractive for long stroke applications.However,low force capability is their major defect.To solve this issue,new LVFR and LWFFR machine topologies were proposed in recent work,while lacking studies on their force improvement mechanism and further force evaluation.In this paper,LVFR and LWFFR machines with improved force performance are comparatively studied with the emphasis on their force capabilities.The operation principle of the two machines is analyzed based on magnetic field harmonics produced by flux modulation.Contributions of air-gap flux density harmonic components to no-load back electromagnetic forces of the two machines are analyzed and the average force equation is derived.Moreover,force capabilities of the both machines are investigated by means of the time-stepping finite-element analysis to verify the theoretical analysis.
文摘Metamaterials have been receiving an increasing amount of interest in recent years. As a type of metamaterial, pentamode materials (PMs) approximate the elastic properties of liquids. In this study, a finite-element analysis was conducted to predict the mechanical properties of PM structures by altering the thin wall thicknesses and layer numbers to obtain an outstanding load-bearing capacity. It was found that as the thin wall thickness increased from 0.15 to 0.45 mm, the compressive modulus of the PM structures increased and the Poisson’s ratio decreased. As the layer number increased, the Poisson’s ratio of the PM structures increased rapidly and reaches a stable value ranging from 0.50 to 0.55. Simulation results of the stress distribution in the PM structures confirmed that stress concentrations exist at the junctions of the thin walls and weights. For validation, Ti–6Al–4V specimens were fabricated by selective laser melting (SLM), and the mechanical properties of these specimens (i.e., Poisson’s ratio and elastic modulus) were experimentally studied. Good consistency was achieved between the numerical and experimental results. This work is beneficial for the design and development of PM structures with simultaneous load-bearing capacity and pentamodal properties.
基金This work was supported by the National Natural Science Foundation of China under Grant Nos.12004078 and 61874033the State Key Lab of ASIC and Systems,the Science and Technology Commission of Shanghai Municipality Award/Grant Nos.22QA1400900 and 22WZ2502200Fudan University 2021MS001,2021MS002 and 2020KF006.
文摘Interdigitated transducers(IDTs)were originally designed as delay lines for radars.Half a century later,they have found new life as actuators for microfluidic systems.By generating strong acoustic fields,they trigger nonlinear effects that enable pumping and mixing of fluids,and moving particles without contact.However,the transition from signal processing to actuators comes with a range of challenges concerning power density and spatial resolution that have spurred exciting developments in solid-state acoustics and especially in IDT design.Assuming some familiarity with acoustofluidics,this paper aims to provide a tutorial for IDT design and characterization for the purpose of acoustofluidic actuation.It is targeted at a diverse audience of researchers in various fields,including fluid mechanics,acoustics,and microelectronics.
基金supported by the National Natural Science Foundation of China (Grant Nos. 61204056,61234004,90923037,and 11074247)the Jilin ProvincialScience and Technology Development Plan Item (Grant Nos. 201105025 and 20116011)
文摘The output performance of a 980-nm broad-area vertical-cavity surface-emitting laser(VCSEL) is improved by optimizing the p-electrode diameter in this study.Based on a three-dimensional finite-element method,the current density distribution within the active region of the VCSEL is optimized through the appropriate adjustment of the p-electrode diameter,and uniform current-density distribution is achieved.Then,the effects of this optimization are studied experimentally.The L-I-V characteristics under different temperatures of the VCSELs with different p-electrode diameters are investigated,and better temperature stability is demonstrated in the VCSEL with an optimized p-electrode diameter.The far-field measurements show that with an injected current of 2 A,the far-field divergence angle of the VCSEL with an optimized p-electrode diameter is 9°,which is much lower than the far-field angle of the VCSEL without this optimization.Also the VCSEL with an optimized p-electrode diameter shows a better near-field distribution.
基金This work was supported by the Key Research and Development Program of Jiangsu Province(BE2018107)by the Six Talent Peaks Project of Jiangsu Province(2017-KTHY-011)by the Graduate Scientific Research Innovation Project of Jiangsu Province(KYCX18_2248).
文摘Due to their excellent efficiency,power density and constant power speed region,interior permanent-magnet(IPM)machines are very suitable for electric vehicles(EVs).This paper proposed a new IPM rotor topology,which can offer high reluctance torque,wide constant power speed range and excellent overload capability.Besides,five rotor topologies with integral-slot distributed-windings IPM machines,including four existing IPM topologies and the proposed IPM topology,are designed optimally.Their characteristics,which include d-q axis inductances,saliency ratios,electromagnetic torques,corresponding torque ripples,back-electromotive forces(EMFs),overload capabilities and flux weakening performances are evaluated quantitatively.Finally,a three phase 48s8p hybrid rotor PM machine is built to verify the performances of the proposed IPM machine.This work provides some general concepts for machine developers who are willing to build IPM machines for high-performance EV applications.
基金support from the National Natural Science Foundation of China(Grant Nos.51778575,52078457).
文摘A novel anchorage for long-span suspension bridges,called pile-caisson composite structures,was recently proposed by the authors in an attempt to reduce the construction period and costs.This study aims to investigate the displacement and force behavior of piles in a pile-caisson composite structure under eccentric inclined loading considering different stratum features.To this end,both 1g model tests and three-dimensional numerical simulations were performed.Two groups of 1g model tests were used to validate the finite-element(FE)method.Parametric studies were then performed to investigate the effects of groundwater level,burial depth of the pile-caisson composite structure,and distribution of soil layers on the performance of the pile-caisson composite structure.The numerical analyses indicated that the influence of the groundwater level on the stability of the caisson was much greater than that of the piles.In addition,increasing the burial depth of the pile-caisson composite structure can assist in reducing the displacements and improving the stability of the pile-caisson composite structure.In addition,the distribution of soil layers can significantly affect the stability of the pile-caisson composite structure,especially the soil layer around the caisson.
基金the Chongqing Construction Science and Technology Plan Project(No.2019-0045)National Natural Science Foundation of Chongqing,China(No.cstc2018jcyjAX0632)Science and Technology Research Program of Chongqing Municipal Education Commission(No.KJZDK201900102).
文摘Jet grouting slabs are widely used in deep excavations owing to their effectiveness for reducing the deflection of the diaphragm wall and the prop forces acting on the struts and improving the basal-heave stability.In this paper,according to case histories in Singapore,a series of finite-element numerical simulations are performed to evaluate the effects of jet grouting slabs on responses to deep braced excavations.On the basis of a parametric sensitivity study,a reasonable thickness of jet grouting slabs is proposed.The effects of the wall depth,wall stiffness,soft-clay thickness,and stiffness on the performance of the jet grouting slabs are assessed by comparing and analyzing a series of simulation results.It is found that the soft-clay thickness significantly affects the wall deflection and basal heave in deep excavation.During the design of support structures,soil profiles should be considered first.The findings of this study provide a reference and guidance for the support system design of similar projects.
基金Supported by National Natural Science Foundation of China(51977099,51777090)Key Research and Development Program of Jiangsu Province(BE2018107)Six Talent Peaks Project of Jiangsu Province(2017-KTHY-011).
文摘In this study,several types of linear actuators that adopt different permanent-magnet(PM)topologies are studied and compared.These linear actuators are based on the concept of PM magnetic screw transmission,which offers high force density,high reliability,and overload protection.Using different magnetic configurations and assembly methods,these linear actuators are designed and optimized for a fair comparison.Initially,based on the operating principle and maximum thrust force,the surface-mounted magnetic screw is described and optimized.Furthermore,the embedded magnetic screw,Halbach array magnetic screw,and field modulated magnetic screw are investigated and compared.Their electromagnetic performances,such as thrust force,torque,magnetic losses,and demagnetization effects are analytically assessed and verified using finite-element analysis.Finally,a prototype of the surface-mounted magnetic screw is developed to validate the predictions.
