Eddy current dampers (ECDs) have emerged as highly desirable solutions for vibration control due to theirexceptional damping performance and durability. However, the existing constitutive models present challenges tot...Eddy current dampers (ECDs) have emerged as highly desirable solutions for vibration control due to theirexceptional damping performance and durability. However, the existing constitutive models present challenges tothe widespread implementation of ECD technology, and there is limited availability of finite element analysis (FEA)software capable of accurately modeling the behavior of ECDs. This study addresses these issues by developing anewconstitutivemodel that is both easily understandable and user-friendly for FEAsoftware. By utilizing numericalresults obtained from electromagnetic FEA, a novel power law constitutive model is proposed to capture thenonlinear behavior of ECDs. The effectiveness of the power law constitutive model is validated throughmechanicalproperty tests and numerical seismic analysis. Furthermore, a detailed description of the application process ofthe power law constitutive model in ANSYS FEA software is provided. To facilitate the preliminary design ofECDs, an analytical derivation of energy dissipation and parameter optimization for ECDs under harmonicmotionis performed. The results demonstrate that the power law constitutive model serves as a viable alternative forconducting dynamic analysis using FEA and optimizing parameters for ECDs.展开更多
Tuned mass dampers （TMDs） have been widely used in recent years to mitigate structural vibration. However, the damping mechanisms employed in the TMDs are mostly based on viscous dampers, which have several well-kno...Tuned mass dampers （TMDs） have been widely used in recent years to mitigate structural vibration. However, the damping mechanisms employed in the TMDs are mostly based on viscous dampers, which have several well-known disadvantages, such as oil leakage and difficult adjustment of damping ratio for an operating TMD. Alternatively, eddy current damping （ECD） that does not require any contact with the main structure is a potential solution. This paper discusses the design, analysis, manufacture and testing of a large-scale horizontal TMD based on ECD. First, the theoretical model of ECD is formulated, then one large-scale horizontal TMD using ECD is constructed, and finally performance tests of the TMD are conducted. The test results show that the proposed TMD has a very low intrinsic damping ratio, while the damping ratio due to ECD is the dominant damping source, which can be as large as 15% in a proper configuration. In addition, the damping ratios estimated with the theoretical model are roughly consistent with those identified from the test results, and the source of this error is investigated. Moreover, it is demonstrated that the damping ratio in the proposed TMD can be easily adjusted by varying the air gap between permanent magnets and conductive plates. In view of practical applications, possible improvements and feasibility considerations for the proposed TMD are then discussed. It is confirmed that the proposed TMD with ECD is reliable and feasible for use in structural vibration control.展开更多
To enhance the system damping,a permanent magnet set which served as an eddy current damper was added to the magnetic levitation positioning stage which consists of a moving table,four Halbach permanent magnetic array...To enhance the system damping,a permanent magnet set which served as an eddy current damper was added to the magnetic levitation positioning stage which consists of a moving table,four Halbach permanent magnetic arrays,four stators and displacement sensors.The dynamics model of this stage was a complex nonlinear,strong coupling system which made the control strategy to be a focus research.The nonlinear controller of the system was proposed based on the theory of differential geometry.Both simulation and experimental results show that either the decoupling control of the movement can be realized in horizontal and vertical directions,and the control performance was improved by the damper,verifying the validity and efficiency of this method.展开更多
为了改善涡流阻尼器在实际工程中的应用性,利用了外部电源改变装置内部磁通量大小,提出了一种新型主动控制式电磁涡流阻尼器(Electromagnetic Eddy Current Damper,简称EECD)。首先考虑磁回路有效利用磁通量及转动装置放大导体板切割磁...为了改善涡流阻尼器在实际工程中的应用性,利用了外部电源改变装置内部磁通量大小,提出了一种新型主动控制式电磁涡流阻尼器(Electromagnetic Eddy Current Damper,简称EECD)。首先考虑磁回路有效利用磁通量及转动装置放大导体板切割磁感应线的优点,进行阻尼器的结构设计,并对其工作原理进行详细地介绍。然后,利用电磁仿真软件(COMSOL Multiphysics)分析其在不同电流大小的情况下所产生的磁通量大小,并推导出相应磁感应强度理论公式,分析相同匝数,不同电流下的工况,结合实测数据,对比仿真、理论与试验的磁感应强度,验证理论的准确度。最后,推导出该阻尼器在电流稳定时等效阻尼系数,进而得出其电涡流阻尼力。研究结果表明:在研究速度范围内,EECD能达到设计目的,等效阻尼系数、惯质及电涡流阻尼力理论结果与试验结果基本吻合,且EECD阻尼性能接近线性;在研究速度范围内,随着电流的变化,电磁铁产生的磁通量大小及阻尼力也成正比变化;该装置滞回性能相对光滑,重复性较好,说明新型电磁式阻尼器力学性能稳定,具有可行性。展开更多
针对现有结构模型减振实验用调谐质量阻尼器(Tuned Mass Damper,TMD)难以实现TMD刚度与阻尼参数完全分离、阻尼参数试验过程中无法保持恒定且难以调整问题,研制微型永磁式电涡流阻尼TMD。其性能试验与分析结果表明,微型TMD采用电涡流阻...针对现有结构模型减振实验用调谐质量阻尼器(Tuned Mass Damper,TMD)难以实现TMD刚度与阻尼参数完全分离、阻尼参数试验过程中无法保持恒定且难以调整问题,研制微型永磁式电涡流阻尼TMD。其性能试验与分析结果表明,微型TMD采用电涡流阻尼装置既能确保刚度与阻尼参数的有效分离,亦能实现阻尼参数稳定、简单易调。通过某大跨度人行桥模型一阶横向振动模态自由振动减振实验识别获得结构模态阻尼比及强迫振动减振实验识别获得结构模态阻尼比、结构动力响应放大倍数、结构与TMD运动相位差等,证实微型永磁式电涡流阻尼TMD用于结构模型减振实验的可行性与有效性。展开更多
文摘Eddy current dampers (ECDs) have emerged as highly desirable solutions for vibration control due to theirexceptional damping performance and durability. However, the existing constitutive models present challenges tothe widespread implementation of ECD technology, and there is limited availability of finite element analysis (FEA)software capable of accurately modeling the behavior of ECDs. This study addresses these issues by developing anewconstitutivemodel that is both easily understandable and user-friendly for FEAsoftware. By utilizing numericalresults obtained from electromagnetic FEA, a novel power law constitutive model is proposed to capture thenonlinear behavior of ECDs. The effectiveness of the power law constitutive model is validated throughmechanicalproperty tests and numerical seismic analysis. Furthermore, a detailed description of the application process ofthe power law constitutive model in ANSYS FEA software is provided. To facilitate the preliminary design ofECDs, an analytical derivation of energy dissipation and parameter optimization for ECDs under harmonicmotionis performed. The results demonstrate that the power law constitutive model serves as a viable alternative forconducting dynamic analysis using FEA and optimizing parameters for ECDs.
基金State Key Program of Natural Science Foundation of China Under Grant No.50738002
文摘Tuned mass dampers （TMDs） have been widely used in recent years to mitigate structural vibration. However, the damping mechanisms employed in the TMDs are mostly based on viscous dampers, which have several well-known disadvantages, such as oil leakage and difficult adjustment of damping ratio for an operating TMD. Alternatively, eddy current damping （ECD） that does not require any contact with the main structure is a potential solution. This paper discusses the design, analysis, manufacture and testing of a large-scale horizontal TMD based on ECD. First, the theoretical model of ECD is formulated, then one large-scale horizontal TMD using ECD is constructed, and finally performance tests of the TMD are conducted. The test results show that the proposed TMD has a very low intrinsic damping ratio, while the damping ratio due to ECD is the dominant damping source, which can be as large as 15% in a proper configuration. In addition, the damping ratios estimated with the theoretical model are roughly consistent with those identified from the test results, and the source of this error is investigated. Moreover, it is demonstrated that the damping ratio in the proposed TMD can be easily adjusted by varying the air gap between permanent magnets and conductive plates. In view of practical applications, possible improvements and feasibility considerations for the proposed TMD are then discussed. It is confirmed that the proposed TMD with ECD is reliable and feasible for use in structural vibration control.
基金Supported by the National Natural Science Foundation of China (60674052)
文摘To enhance the system damping,a permanent magnet set which served as an eddy current damper was added to the magnetic levitation positioning stage which consists of a moving table,four Halbach permanent magnetic arrays,four stators and displacement sensors.The dynamics model of this stage was a complex nonlinear,strong coupling system which made the control strategy to be a focus research.The nonlinear controller of the system was proposed based on the theory of differential geometry.Both simulation and experimental results show that either the decoupling control of the movement can be realized in horizontal and vertical directions,and the control performance was improved by the damper,verifying the validity and efficiency of this method.
文摘为了改善涡流阻尼器在实际工程中的应用性,利用了外部电源改变装置内部磁通量大小,提出了一种新型主动控制式电磁涡流阻尼器(Electromagnetic Eddy Current Damper,简称EECD)。首先考虑磁回路有效利用磁通量及转动装置放大导体板切割磁感应线的优点,进行阻尼器的结构设计,并对其工作原理进行详细地介绍。然后,利用电磁仿真软件(COMSOL Multiphysics)分析其在不同电流大小的情况下所产生的磁通量大小,并推导出相应磁感应强度理论公式,分析相同匝数,不同电流下的工况,结合实测数据,对比仿真、理论与试验的磁感应强度,验证理论的准确度。最后,推导出该阻尼器在电流稳定时等效阻尼系数,进而得出其电涡流阻尼力。研究结果表明:在研究速度范围内,EECD能达到设计目的,等效阻尼系数、惯质及电涡流阻尼力理论结果与试验结果基本吻合,且EECD阻尼性能接近线性;在研究速度范围内,随着电流的变化,电磁铁产生的磁通量大小及阻尼力也成正比变化;该装置滞回性能相对光滑,重复性较好,说明新型电磁式阻尼器力学性能稳定,具有可行性。
文摘针对现有结构模型减振实验用调谐质量阻尼器(Tuned Mass Damper,TMD)难以实现TMD刚度与阻尼参数完全分离、阻尼参数试验过程中无法保持恒定且难以调整问题,研制微型永磁式电涡流阻尼TMD。其性能试验与分析结果表明,微型TMD采用电涡流阻尼装置既能确保刚度与阻尼参数的有效分离,亦能实现阻尼参数稳定、简单易调。通过某大跨度人行桥模型一阶横向振动模态自由振动减振实验识别获得结构模态阻尼比及强迫振动减振实验识别获得结构模态阻尼比、结构动力响应放大倍数、结构与TMD运动相位差等,证实微型永磁式电涡流阻尼TMD用于结构模型减振实验的可行性与有效性。
