Assistant Professor / Department of Mechanical Engineering
Department of Mechanical Engineering
Faculty of Engineering

E-Mail
Phone
092-802-3183
Fax
092-802-0001
Doctor of Engineering
Field of Specialization
Mechanics and Control Engineering
Outline Activities
(1) I have been researching the design of some kinds of magnetic dampers: the combined-magnet-type magnetic damper, the magnetic damper applying Halbach magnet array, etc . In addition, I studies the modeling of the magnetic skin effect on magnetic dampers.
(2)I research the reduction of the damage from low-frequency vibration generated by heat pumps, windmills and etc, by applying a high performance magnetic damper or another dampers.

Research
Research Interests
• High performance magnetic damper for rotating machines
keyword : Magnetic Damper, Eddy-current Damper, Faraday's law, Lorentz Force
2016.04Magnetic damper based on Lorentz force is the damper using the phenomenon that when a conducting plate moves perpendicularly to magnetic flux densities, drag-force is generated on it. On the other hand, new magnetic damper on our study is the damper utilise magnetic flux densities parallel to the movement of a conducting plate. The experimental setup to demonstrate the principle of this damper is fabricated and is modeled in detail now..
• Study on modeling of vertical moving type magnetic dampers
keyword : Magnetic damper, Eddy-current Damper, Faraday's law, Induced current, damping
2012.04The magnetic damper in our study bases on Lorentz force. In other words, if there is a static nonuniform magnetic field, the component of which is perpendicular to the direction of the movement of a conducting plate, eddy currents flowing in the conducting plate produce the magnetic force of drag. Mainly, I have been researching two type magnetic dampers using circular magnets or ball magnets..
• Study on modeling of parallel moving type magnetic dampers
keyword : Magnetic damper, Eddy-current Damper, Faraday's law, Induced current, damping
2013.04The magnetic damper in our study bases on Lorentz force. In other words, if there is a static nonuniform magnetic field, the component of which is perpendicular to the direction of the movement of a conducting plate, eddy currents flowing in the conducting plate produce the magnetic force of drag. Mainly, I have been researching two type magnetic dampers using circular magnets or ball magnets..
• High performance magnetic damper composed of a combined magnet for rotating machines
keyword : Magnetic Damper, Eddy-current Damper, Faraday's law, Lorentz Force
2007.04～2010.07Magnetic damper based on Lorentz force is the damper using the phenomenon that when a conducting plate moves perpendicularly to magnetic flux densities, drag-force is generated on it. On the other hand, new magnetic damper on our study is the damper utilise magnetic flux densities parallel to the movement of a conducting plate. The experimental setup to demonstrate the principle of this damper is fabricated and is modeled in detail now..
• Unstable Vibrations of Rotaing Machines Caused by a Magnetic Damper
keyword : Electromagnet-Induced Vibration, Unstable Vibration, Magnetic Damper, Eddy-current Damper
1993.04～2004.08The magnetic damping force is produced by not only a rotating-conductor-type magnetic damper composed of a rotating conductor and a static magnet but also a rotating-magnet-type magnetic damper composed of a rotating magnet and a static conductor. In the case of the rotatong-conductor-type magnetic damper, it was demonstrated analytically and experimentally that a rotating-conductor-type magnetic damper for a rotating machine caused unstable vibrations at a rotating speed over the critical speed. On the other hand, the rotating-magnet-type magnetic damper never produces unstable vibrations. The analytical results agree well with the experimental ones..
Papers
 1 Modeling of magnetic damper composed of ring magnet and coaxially and relatively moving conducting disk considering skin effect. 2 Yoshihisa Takayama, Takahiro KONDOU, Magnetic Damper Consisting of a Combined Hollow Cylinder Magnet and Conducting Disks, Transactions of the ASME, 10.1115/1.4024094, 135, 051007-1, OCTOBER 2013, Vol. 135 / 051007-1DOI: 10.1115/1.4024094, 2013.10, It is recognized that unstable vibration occurs at a rotating speed above the major criticalspeed by a rotating-conducting-disk type magnetic damper, but not by a rotating-circular-magnet type magnetic damper. In addition, magnetic dampers generally haverelatively poor damping performance. In the present work, two new rotating-circularmagnettype magnetic dampers, (which consist of a combined hollow cylinder magnetwith alternating directional magnetic poles), are introduced and their design method ispresented. Applying the modeling method that the authors have been studying, a prototypemagnetic damper with a combined magnet is fabricated and the damping ratios fromthe analytical results agree well with those from the experimental results. Rotating testsare performed and it is confirmed that unstable vibration does not occur at a rotatingspeed of more than twice the major critical speed. Based on these findings, an optimallydesigned magnetic damper with a combined magnet is developed and a damping ratio of0.25 (damping coefficient of 215 Ns/m) is achieved.. 3 Study on Magnetic Damper Composed of Combined Magnets(Magnetic Damper Composed of Basic Halbach Magnet Arrays). 4 Magnetic Damper Consisting of Circular Coil and Columnar Magnet. 5 Yoshihisa TAKAYAMA Atsuo SUEOKA Takahiro KONDOU, Modeling of Moving-Conductor Type Eddy Current Damper, Journal of System Design and Dynamics, DOI: 10.1299/jsdd.2.1148, Vol.2, No.5, 1148-1159, Vol.2, No.5, 2008, pp.1148-1159[ https://www.jstage.jst.go.jp/article/jsdd/2/5/2_5_1148/_pdf] DOI: 10.1299/jsdd.2.1148, 2008.11. 6 Yoshihisa TAKAYAMA Atsuo SUEOKA Takahiro KONDOU, Magnetic Damper Consisting of Spherical Magnet and Conducting Shell, 12th Asia Pacific Vibration Conference, CD-ROM Paper No.20APVC2007 Program and Abstracts, pp.23, 2007.08. 7 Yoshihisa TAKAYAMA Atsuo SUEOKA and Takahiro KONDOU, Modeling of Eddy Current Damper Composed of Spherical Magnet and Conducting Shell, 2006 ASME International Mechanical Engineering Congress and Exposition, IMECE2006-13114, 2006.11. 8 Vibration Reduction of a Rotating Machinery by Magnetic Damper with Rotating Circular Magnet(Nonoccurrence of an Unstable Vibration Caused by Magnetic Damping Force), Transactions of the Japan Society of Mechanical Engineering, Series C, Vol.70, No.696 (2004), pp.2195-2202, (in Japanese)[https://www.jstage.jst.go.jp/article/kikaic1979/70/696/70_696_2195/_pdf]. 9 Y. Takayama, A. Sueoka, T. Kondou, Fundamental analysis of magnetic damping force for a rotating machine, Theoretical and Applied Mechanics Japan, Vol.52 (2003), pp.137-144, [ https://www.jstage.jst.go.jp/article/nctam/52/0/52_0_137/_pdf ] , 2003.10. 10 Unstable Vibration of a Rotating Machine Caused by a Magnetic Damping Force, Transactions of the Japan Society of Mechanical Engineering, Series C, Vol.68, No.665 (2002), pp.16-23, (in Japanese)[https://www.jstage.jst.go.jp/article/kikaic1979/68/665/68_665_16/_pdf]. 11 Yoshihisa TAKAYAMA, Atsuo SUEOKA and Takahiro KONDOU, Unstable Vibrations of Rotating Machinery Caused by Magnetic Damper (Experiments and Electric Circuit Model), Proceedings of the Asia-Pacific Vibration Conference '99, Vol.1, (1999), 198 -203, 1999.12. 12 Yoshihisa TAKAYAMA, Atsuo SUEOKA and Shinji FUJIMOTO, Unstable Vibrations of Rotating Machinery Generated in DC Current Electromagnet Field, Proceedings of the Asia-Pacific Vibration Conference '97, Vol.2,1027 -1032, 1997.11.
Presentations
 1 Modeling of Parallel Motion Type Magnetic Damper Composed of Conducting Plate and Magnets with Steel PlatesEddy currents are generated by the relative motion of a conducting plate and a magnet. Magnetic damper is a device that utilizes the magnetic drag force produced by the eddy current. The author call the magnetic damper moving parallel to the conducting disk the parallel-motion type magnetic damper. The author previously proposed the vector potential method for magnetic damper. The method has a good point that magnetic damping force can be calculated accuracy when a parallel-motion type magnetic damper is composed of rectangular magnets with alternating directional magnetic poles and a conducting plate. Generally ferromagnetic metal, for example a steel plate (S45C), has a property known as concentrating magnetic flux into itself. In this paper, using image method, we propose the new vector potential method for the magnetic damper with steel plates outside the rectangular magnets with alternating directional magnetic poles. The image method is a method for calculating a magnetic field by adding image currents in order to satisfy the boundary conditions between a magnetic material area and an air area in the magnetic field and the vector potential field. Damping ratios calculated by the new vector potential method are compared to the tests. As a result, analytical results are in good agreement with the experimental results.. 2 Study on Magnetic Damper Composed of Combined Magnets(Magnetic Damper Composed of Rectangular Magnets). 3 Study on Magnetic Damper Composed of Combined Magnets(Magnetic Damper Composed of Linear Array Magnets). 4 Influence of Magnetic Skin Effect on Magnetic Damper. 5 Study on Magnetic Damper Composed of Combined Magnet. 6 Magnetic Damper consisting of Ball-type Magnet and Conducting Shell. 7 A Magnetic Damper Based on Lorentz Force (Magnetic Damper Consisting of Hollow-Cylindrical Conductor and Ring-Shaped Magnet ). 8 Magnetic Damper Based on Lorentz Force (Experiments and Speculations). 9 Magnetic Damper Using Quadrilateral Magnet. 10 Unstable Vibration of a Rotor caused by a Magnetic Damper.
Membership in Academic Society
• JAPAN Society of Mechanical Engineers
• American Society of Mechanical Engineers
• JAPAN Society of Applied Electomagnetics and Mechanics
Educational
Educational Activities
As to Mechanical Engineering laboratory training, the teaching folowwing the syllabus is conducted and the improvement of the contents are made.
The progress of research of the graduation thesis and master's thesis are closely conducted.
Other Educational Activities
• 2010.07.
• 2009.09.
Social
Professional and Outreach Activities
I have a relationship with overseas reseachers by presentations at the international conferences and publishing in an academic journal..