Stabilization of a Buckled Beam by High-Frequency Excitation: Linear Analysis and Experiments

2005 ◽  
Author(s):  
Koji Tsumoto ◽  
Hiroshi Yabuno ◽  
Nobuharu Aoshima
Keyword(s):  
High Frequency ◽  
Control Method ◽  
Compressive Force ◽  
Pitchfork Bifurcation ◽  
Complex Structures ◽  
Stabilization Control ◽  
Buckled Beam ◽  
High Frequency Excitation ◽  
Frequency Excitation ◽  
The Stability

Beam is one of the fundamental elements in complex structures. It is very significant to clarify its stability under the various circumstances. In particular, the buckling phenomenon, which is characterized as a pitchfork bifurcation, has accepted much interest by many researchers. In this paper, we propose a stabilization control method for the first-mode buckling phenomenon in the clamped-clamped beam without feedback control. We analyze the stability of a buckled beam under high frequency excitation in linear theory. It is theoretically clarified and experimentally that the high-frequency excitation shifts the bifurcation point (the critical compressive force) and prevents the beam buckling.

Control of a Buckled Beam Subjected to a Compressive Force

2001 ◽  
Author(s):  
Hiroshi Yabuno ◽  
Kazuya Ando ◽  
Nobuharu Aoshima
Keyword(s):  
Steady State ◽  
Disturbance Observer ◽  
Coulomb Friction ◽  
Control Method ◽  
Compressive Force ◽  
Restoring Force ◽  
Velocity Feedback ◽  
Stabilization Control ◽  
Buckled Beam ◽  
Position Feedback

Abstract In this paper, we deal with a stabilization control for the buckled beam subjected to a compressive force. It is easily predicted that by applying a restoring force to the beam (P control), which is proportional to the deflection, the critical compressive force for the buckling is increased. However it is theoretically and experimentally clarified in our former study that in the neighborhood of the critical point, the effect of Coulomb friction at the supporting points is relatively increased even if it is very slight. It follows that the beam cannot be stabilized to the trivial steady state only by using the position feedback control and also velocity feedback. In this paper, we propose a stabilization control method of the beam to the trivial steady state by the aid of disturbance observer. Furthermore, the validity of the theoretically proposed method is experimentally confirmed.

Experimental investigation of a buckled beam under high-frequency excitation

2007 ◽  
Vol 77 (5) ◽  
pp. 339-351 ◽  
Author(s):  
Hiroshi Yabuno ◽  
Koji Tsumoto
Keyword(s):  
Experimental Investigation ◽  
High Frequency ◽  
Buckled Beam ◽  
High Frequency Excitation ◽  
Frequency Excitation

Multibody Dynamics and Vibration Analysis for Railcar Wheelset Design Studies

2003 ◽  
Author(s):  
Werner Schiehlen ◽  
Holger Claus
Keyword(s):  
High Frequency ◽  
Bogie Frame ◽  
Design Studies ◽  
Dynamic Analyses ◽  
High Frequency Excitation ◽  
Frequency Excitation ◽  
Railway Passenger ◽  
The Stability ◽  
Dynamics And Vibration ◽  
Unsprung Mass

This paper presents design studies and dynamic analyses of a railway passenger coach. The wheelset excitations are deterministic due to polygonalization generating noise in ICE passenger coaches and stochastic due to track irregularities. The strength of conventional wheelsets against vibrations due to polygonalized wheels is investigated. Radialelastic wheels reduce the unsprung mass and isolate the bogie frame and carbody from the medium and high frequency excitation caused by the wheel/rail interaction. A parameter optimization of such wheels leads to considerably reduced carbody vibrations. Stability tests are performed for various parameter sets of radialand lateralelastic wheels. The results show that designs with increased bending stiffness and improved parameters are feasible, and guarantee the stability of the wheelset motion as well as a noise reduction.

Bifurcations of a High-Frequency Horizontally Excited Double Pendulum

2011 ◽  
Author(s):  
Hiroshi Yabuno ◽  
Kazuya Endo
Keyword(s):  
Bifurcation Point ◽  
High Frequency ◽  
Excitation Frequency ◽  
Pitchfork Bifurcation ◽  
Vertical Position ◽  
Double Pendulum ◽  
Bifurcation Phenomena ◽  
Underactuated Manipulator ◽  
High Frequency Excitation ◽  
Frequency Excitation

The bifurcation phenomena produced in a double pendulum under high-frequency horizontal excitation are theoretically and experimentally examined. It has been well known as dynamic stabilization phenomenon that vertical high-frequency excitation can stabilize inverted pendulum. The phenomenon is produced through a sub-critical pitchfork bifurcation. On the other hand, under horizontal high-frequency excitation, the pendulum undergoes a supercritical pitchfork bifurcation and is swung up from the downward vertical position. There have so far been many researches on such dynamics of a single pendulum under the vertical and horizontal high-frequency excitations, but few investigations on multi-degrees-of-freedom system. Also, the utilization of these bifurcations phenomena under the high-frequency excitation is proposed for motion control of underactuated manipulators, but most researches on application is confined to a single pendulum to which a free of two-link underactuated manipulator corresponds. In this paper, toward the development of a three-link underactuated manipulator, we deal with a double pendulum to which two free links of the three-link underactuated manipulator correspond, and theoretically and experimentally investigate bifurcation phenomena in the two pendulums. First, we theoretically predict two pitchfork bifurcation points while increasing the excitation frequency by linear amplitude equations derived using the method of multiple scales. Furthermore, we experimentally examine the swing-up of the pendulums after the first pitchfork bifurcation point and observe that the system has the four types of stable configurations beyond the second pitchfork bifurcation point.

Stabilization Control of a Simply Supported Buckled Beam

2003 ◽  
Vol 9 (3-4) ◽  
pp. 449-473 ◽  
Author(s):  
Hiroshi Yabuno ◽  
Kazuya Ando ◽  
Nobuharu Aoshima
Keyword(s):  
Steady State ◽  
Coulomb Friction ◽  
Control Method ◽  
Compressive Force ◽  
Control Force ◽  
Lateral Direction ◽  
Simply Supported ◽  
Stabilization Control ◽  
Straight Position ◽  
Buckled Beam

A stabilization control scheme for a simply supported buckled beam subjected to a compressive force is proposed theoretically and experimentally. It is easily predicted that the application of a control force based on P-control (control force is proportional to the deflection) increases the stiffness of the beam as well as the critical compressive force for the buckling. However, P-control cannot stabilize the buckled beam into the trivial steady state (straight position) for the following reason. Because the simply supported point is composed of rotatingequipment such as radial bearing, there is Coulomb friction in the circumferential direction around the rotatingaxis at that point and this friction causes the bendingmoment at the supporting point. As theoretically and experimentally clarified in our former study, in the neighborhood of the critical point, this effect of Coulomb friction produces an infinite number of fixed points for a compressive force. Then because the sum of the equivalent destabilization force in the lateral direction owing to the compressive force, originally existing stiffness of the beam, and the control force is spontaneously balanced with the effect of the bendingmoment due to the Coulomb friction, the beam cannot be stabilized to the trivial steady state by using the P-control. Also, in the same manner, the beam cannot be stabilized to the trivial steady state even by proportional derivative (PD) control. In this paper, we regard the effect of the Coulomb friction as a disturbance, and by estimating the disturbance with the aid of a disturbance observer, we stabilize the simply supported buckled beam to the trivial steady state. Furthermore, we conduct experiments using simple apparatus and we confirm the validity of the theoretically proposed control method.

Pitch-synchronous time-scaling for high-frequency excitation regeneration

2005 ◽  
Author(s):  
Joao P. Cabral ◽  
Luis C. Oliveira
Keyword(s):  
High Frequency ◽  
Time Scaling ◽  
High Frequency Excitation ◽  
Frequency Excitation ◽  
Synchronous Time

Evaluation on iron loss of reactor core under high frequency excitation by magnetic field analysis

2015 ◽  
Author(s):  
S. Odawara ◽  
K. Sawatari ◽  
S. Yamamoto ◽  
K. Fujisaki ◽  
Y. Shindo ◽  
...  
Keyword(s):  
Magnetic Field ◽  
High Frequency ◽  
Reactor Core ◽  
Field Analysis ◽  
Iron Loss ◽  
Magnetic Field Analysis ◽  
High Frequency Excitation ◽  
Frequency Excitation

scholarly journals Empirical Expression for AC Magnetization Harmonics of Magnetic Nanoparticles under High-Frequency Excitation Field for Thermometry

Nanomaterials ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 2506
Author(s):  
Zhongzhou Du ◽  
Dandan Wang ◽  
Yi Sun ◽  
Yuki Noguchi ◽  
Shi Bai ◽  
...  
Keyword(s):  
Magnetic Nanoparticles ◽  
High Frequency ◽  
Planck Equation ◽  
Magnetization Dynamics ◽  
Excitation Field ◽  
Fokker Planck Equation ◽  
High Frequency Excitation ◽  
Frequency Excitation ◽  
Ac Magnetization ◽  
Fokker Planck

The Fokker–Planck equation accurately describes AC magnetization dynamics of magnetic nanoparticles (MNPs). However, the model for describing AC magnetization dynamics of MNPs based on Fokker-Planck equation is very complicated and the numerical calculation of Fokker-Planck function is time consuming. In the stable stage of AC magnetization response, there are differences in the harmonic phase and amplitude between the stable magnetization response of MNPs described by Langevin and Fokker–Planck equation. Therefore, we proposed an empirical model for AC magnetization harmonics to compensate the attenuation of harmonics amplitude induced by a high frequency excitation field. Simulation and experimental results show that the proposed model accurately describes the AC M–H curve. Moreover, we propose a harmonic amplitude–temperature model of a magnetic nanoparticle thermometer (MNPT) in a high-frequency excitation field. The simulation results show that the temperature error is less than 0.008 K in the temperature range 310–320 K. The proposed empirical model is expected to help improve MNPT performance.

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