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.

scholarly journals Experimental investigation on vibration characteristics of the medium–low-speed maglev vehicle–turnout coupled system

2021 ◽  
Author(s):  
Miao Li ◽  
Dinggang Gao ◽  
Tie Li ◽  
Shihui Luo ◽  
Weihua Ma ◽  
...  
Keyword(s):  
Dynamic Performance ◽  
Field Tests ◽  
Coupled System ◽  
Vibration Characteristics ◽  
Operating Conditions ◽  
Transport Systems ◽  
Ride Quality ◽  
Optimized Design ◽  
Line System ◽  
Low Speed

AbstractThe steel turnout is one of the key components in the medium–low-speed maglev line system. However, the vehicle under active control is prone to vehicle–turnout coupled vibration, and thus, it is necessary to identify the vibration characteristics of this coupled system through field tests. To this end, dynamic performance tests were conducted on a vehicle–turnout coupled system in a medium–low-speed maglev test line. Firstly, the dynamic response data of the coupled system under various operating conditions were obtained. Then, the natural vibration characteristics of the turnout were analysed using the free attenuation method and the finite element method, indicating a good agreement between the simulation results and the measured results; the acceleration response characteristics of the coupled system were analysed in detail, and the ride quality of the vehicle was assessed by Sperling index. Finally, the frequency distribution characteristics of the coupled system were discussed. All these test results could provide references for model validation and optimized design of medium–low-speed maglev transport systems.

scholarly journals Quantitative Evaluation for Reinforcement Effect of Auxiliary Steel Beams Based on Running Safety and Dynamic Response

2021 ◽  
Vol 2021 ◽  
pp. 1-16
Author(s):  
Gong Kai ◽  
Liu Linya ◽  
Xiang Jun ◽  
Yang Haiming ◽  
Yu Cuiying
Keyword(s):  
Dynamic Response ◽  
Evaluation Method ◽  
Calculation Model ◽  
Vertical Vibration ◽  
Vibration Response ◽  
Steel Beams ◽  
Steel Beam ◽  
Allowable Limit ◽  
Running Safety ◽  
Spatial Vibration

Aiming at the existing heavy-haul railway, bridges hardly meet the transportation requirements. Based on the spatial vibration calculation model of the freight train–track–bridge (FTTB) system, the FTTB spatial vibration model under the condition of auxiliary steel beam reinforcement is established. Besides, according to the random analysis method of train derailment energy, coming up with an evaluation method of auxiliary steel beam reinforcement is based on safety and dynamic response, which is used to discuss the train safety and the change law of FTTB system vibration response. The results show that the derailment resistance of the FTTB system is increased by 22.6% after the auxiliary steel beam is reinforced. Compared with the previous speed (115.56 km/h), the speed is 132.73 km/h after the auxiliary steel beam reinforcement; at the same time, the allowable limit speed increases from 92.49 km/h to 106.18 km/h. In addition, the reinforcement of the auxiliary steel beam can not only effectively reduce the lateral vibration response of the FTTB system under the action of empty wagon but also effectively decline the vertical vibration response of the FTTB system under the action of the loaded wagon, which can meet the stability requirement for running at the speed of 90 km/h. In summary, the reinforcement of auxiliary steel beams can improve the running safety of trains, reduce the vibration response of the FTTB system, and meet the requirements of operation stability.

Nonlinear Module Control of Maglev Levitation System Based on Feedback Linearization

2013 ◽  
Vol 274 ◽  
pp. 550-554 ◽  
Author(s):  
Jin Hui Li ◽  
Jie Li
Keyword(s):  
Feedback Linearization ◽  
Coupled Model ◽  
Tracking Performance ◽  
Air Spring ◽  
Low Speed ◽  
Maglev Vehicle ◽  
Levitation System ◽  
Experiment Verification ◽  
Magnetically Levitated

This study develops an electromagnet-air spring-vehicle coupled model of the actively controlled, magnetically levitated system. Based on the coupled model, the nonlinear module controller based on the feedback linearization is adopted. The experiment verification on CMS04 low speed maglev vehicle is carried out; the results show that the tracking performance and decoupling ability of proposed controller is satisfied.

Decoupling Capability of Levitation Frames for Medium-Low Speed Maglev Trains

2021 ◽  
pp. 2150178
Author(s):  
Junxiong Hu ◽  
Weihua Ma ◽  
Shihui Luo ◽  
Wan Liu ◽  
Tianwei Qu ◽  
...  
Keyword(s):  
Structural Parameters ◽  
Stability Control ◽  
Test Method ◽  
Air Spring ◽  
Low Speed ◽  
End Set

Medium-low speed maglev trains (MSMTs) with a levitation gap of only 8–10[Formula: see text]mm need an adequate decoupling capability on the levitation frames to ensure stability control in levitation, while preventing the train from rolling sideways when in landing. Based on the geometric and kinematic relationships, two types of levitation frames are studied, i.e. levitation frame with end-set air spring (LFEAS) and levitation frame with mid-set air spring (LFMAS). For each levitation frame, the decoupling process and mechanism are analyzed, the analytical equations for the kinematic attitude are derived, the decoupling capability under different excitations is calculated, along with the effect of various structural parameters assessed. In addition, a test method is designed for the rolling of the levitation frame, particularly with the anti-rolling capability of the LFMAS measured. The results indicate that oscillation of the hanger rods and anti-rolling beams can compensate for displacement when the motion of the levitation frame is decoupled, which is the key to the decoupling capability. Also, the position of the anti-rolling devices and the length of hanger rods do not affect significantly the decoupling capability. However, a longer anti-rolling beam is more conducive to decoupling, but it does not affect the anti-rolling capacity of the levitation frame. The maximum roll computed of the LFMAS is 2.84[Formula: see text]mm, which meets the anti-rolling requirement.

scholarly journals Seismic Behavior and Study of RCS Composite Frame Composed of Steel Beams and Strong Concrete Column

2019 ◽  
Vol 15 (2) ◽  
pp. 142-153
Author(s):  
Ahmadreza Khodabandehlo ◽  
Mohamad Taghi Kazemi
Keyword(s):  
Reinforced Concrete ◽  
Seismic Behavior ◽  
Bending Strength ◽  
Steel Beams ◽  
Steel Beam ◽  
Concrete Column ◽  
Moment Frame ◽  
Reinforced Concrete Column ◽  
Long Span ◽  
Composite Frame

AbstractWith spreading of population and increasing of instruction, and also because of limited resources and materials, the demand for using novel materials in building industry has increased. The reinforced concrete columns and steel beams are used in structures with composite moment frame (RCS). Use of compression strength in proportion with concrete and bending strength of steel beam has bestowed these structures less weight than that of concrete structures and made it easier to access the measure of strong column - weak beam especially within long span in these structures. The most important part of these structures is connection of steel beam with the reinforced concrete column. These connections are divided into two general groups of connection with bracing beam and with bracing column from the joint. This paper aims to study the seismic behavior and parameters of RCS composite frame composed of steel beams and strong concrete column. The finite element method was analyzed by ABAQUS software and data analyzed by Excel.

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