Lateral vibration control of a low-speed maglev vehicle in cross winds

2012 ◽  
Vol 15 (3) ◽  
pp. 263-283 ◽  
Author(s):  
J.D. Yau
Keyword(s):  
Vibration Control ◽  
Lateral Vibration ◽  
Low Speed ◽  
Maglev Vehicle

Experimental study on vertical vibration characteristics of medium-low speed maglev vehicle when standing still on steel beams

2021 ◽  
pp. 095440972110324
Author(s):  
Miao Li ◽  
Xiaohao Chen ◽  
Shihui Luo ◽  
Weihua Ma ◽  
Cheng Lei ◽  
...  
Keyword(s):  
Coupled System ◽  
Vertical Vibration ◽  
Vibration Characteristics ◽  
Steel Beams ◽  
Steel Beam ◽  
Air Spring ◽  
Low Speed ◽  
Maglev Vehicle ◽  
Excited Vibration ◽  
Eigen Frequencies

Levitation stability is the very basis for the dynamic operation of Electromagnetic Suspension (EMS) medium-low speed maglev trains (MSMT). However, self-excited vibration tends to occur when the vehicle is standing still above the lightweight lines, which remains a major constraint to the promotion of medium-low speed maglev technology. In order to study the vertical vibration characteristics of the coupled system of MSMT when it is standing still above lightweight lines, levitation tests were carried out on two types of steel beams: steel beam and active girder of the turnout, with a newly developed maglev vehicle using levitation frames with mid-set air spring. Firstly, modal tests were carried out on the steel beam to determine its natural vibration characteristics; secondly, the acceleration signals and the dynamic displacement signals of the air spring obtained at each measurement point were analyzed in detail in both the time and frequency domains, and the vertical ride comfort was assessed by means of the calculated Sperling index. Subsequently, theoretical explanations were given for the occurrence of self-excited vibration of coupled system from the perspective of the vehicle-to-guideway vibration energy input. Results show that the eigen frequencies of the vehicle on the steel beam and the turnout are 9.65 Hz and 2.15 Hz, respectively, the former being close to the natural frequency of the steel beam while the latter being close to the natural frequency of the air spring suspension system, thus causing the self-excited vibration of the coupled system. It is recommended to either avoid the main eigen frequencies of the coupled system or to increase the damping of the corresponding vibration modes to guarantee a reliable coupled system for its long-term performance. These results may provide valuable references for the optimal design of medium-low speed maglev systems.

Rigid Mode Vibration Control and Dynamic Behavior of Hybrid Foil–Magnetic Bearing Turbo Blower

2016 ◽  
Vol 139 (5) ◽  
Author(s):  
Sena Jeong ◽  
Doyoung Jeon ◽  
Yong Bok Lee
Keyword(s):  
Vibration Control ◽  
Dynamic Pressure ◽  
Magnetic Bearing ◽  
Experimental Results ◽  
Low Speed ◽  
Vibration Stability ◽  
Turbo Blower ◽  
Foil Bearing ◽  
Vibration Responses ◽  
Aerodynamic Instability

In this study, experimental and analytical analyses of the vibration stability of a 225 kW class turbo blower with a hybrid foil–magnetic bearing (HFMB) were performed. First, critical speed and unbalance vibration responses were examined as part of the rotordynamic research. Its shaft diameter was 71.5 mm, its total length was 693 mm, and the weight of the rotor was 17.8 kg. The air foil bearing (AFB) utilized was 50 mm long and had a 0.7 aspect ratio. In the experiments conducted, excessive vibration and rotor motion instability occurred in the range 12,000–15,000 rpm, which resulted from insufficient dynamic pressure caused by the length of the foil bearing being too short. Consequently, as the rotor speed increased, excessive rotor motion attributable to aerodynamic and bearing instability became evident. This study therefore focused on improving rotordynamic performance by rectifying rigid mode unstable vibration at low speed, 20,000 rpm, and asynchronous vibration due to aerodynamic instability by using HFMB with vibration control. The experimental results obtained were compared for each bearing type (AFB and HFMB) to improve the performance of the vibration in the low-speed region. The experimental results show that the HFMB technology results in superior vibration stability for unbalance vibration and aerodynamic instability in the range 12,000–15,000 rpm (200–250 Hz). The remarkable vibration reduction achieved from vibration control of the HFMB–rotor system shows that oil-free turbomachinery can achieve excellent performance.

Study on Vibration Control by Modal Analysis of a MAGLEV Vehicle

2002 ◽  
Vol 2002.11 (0) ◽  
pp. 121-124
Author(s):  
Takayuki TOHTAKE ◽  
Ken WATANABE ◽  
Masao NAGAI
Keyword(s):  
Vibration Control ◽  
Modal Analysis ◽  
Maglev Vehicle

Study on the Combustion Noise Characteristic of Low Speed Diesel Engine

2014 ◽  
Vol 945-949 ◽  
pp. 750-753 ◽  
Author(s):  
Li Qi Yan ◽  
Hui Jun Ge
Keyword(s):  
Diesel Engine ◽  
Vibration Control ◽  
Combustion Engine ◽  
Combustion Noise ◽  
Aerodynamic Noise ◽  
Power Device ◽  
Response Analysis ◽  
Cylinder Pressure ◽  
Real Condition ◽  
Low Speed

In recent years, the Low speed two stroke diesel engines are widely used as the main power device of big ship for its so many advantages such as the high power, better economical efficiency and good maintenance. However, the problem of diesel strong vibration and noise becomes a more and more serious at the same time. Because of the Construction Features of marine two-stroke low-speed diesel engine, the structure has to be suffered different kind of forces when it runs. In considering the source of vibration, the whole noise can be divided into combustion noise、machinery noise and aerodynamic noise. The combustion noise caused by cylinder pressure is the most important part of diesel noise. In this paper, the cylinder pressure curves are tested. The internal combustion engine dynamics and the equivalent node load are used in the calculation procedure to achieve the real condition simulation. The loading program is made to simulate the change of cylinder pressure and the move of piston. The transient response of the diesel engine is calculated. The characteristics of diesel caused by cylinder pressure are analyzed.The response analysis can be used to the vibration control.

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