Dynamic Analysis of Tram Vehicles Coupled With the Track System Based on Staggered Iterative Algorithm

2020 ◽  
Vol 15 (6) ◽  
Author(s):  
Yao Shan ◽  
Binglong Wang ◽  
Shunhua Zhou ◽  
Jiawei Zhang ◽  
Aijun Huang
Keyword(s):  
Dynamic Response ◽  
Soft Soil ◽  
Low Frequency ◽  
Vehicle Body ◽  
Frequency Range ◽  
Fe Method ◽  
Coupling System ◽  
Durability Design ◽  
Track System ◽  
Vehicle Structure

Abstract In recent years, a large number of tram–tracks have been constructed in typical soft soil area of China. Infrastructure defects due to the differential foundation settlement are serious issues in this area. To ensure the operation safety of the tram, the influence of different infrastructure defects on the dynamic response of the tram–track system has been investigated in this paper. A dynamic model of a five-module 100% low-floor tram vehicle coupled with a slab track system is developed based on a finite element (FE) method and multibody kinematics. The articulation between different vehicle modules, the wheel–rail nonlinear contact, pad failures, and a cavity in the subgrade have been taken into account in this model. The dynamic response of the vehicle–track coupling system to different operation speeds and infrastructure defects are calculated. Results indicate that the vibration energy of the vehicle body is mainly distributed in the frequency range below 1.5 Hz. This frequency range should be paid special attention in the durability design for the vehicle structure. When the number of the failure pads is larger than 3, the pad failure in tram–track has significant influence on the system dynamic response. A cavity in subgrade has a limited effect on high frequency vibrations (above 100 Hz) of the rail, while the low frequency vibrations (below 75 Hz) of the rail can be obviously increased by cavities in subgrade. The model can be used in the optimization of suspension parameters and the tram vehicle–track coupled vibration analysis.

scholarly journals Implementation of the Spectral Method for Determining of Measuring Instruments' Dynamic Characteristics

2020 ◽  
Vol 11 (2) ◽  
pp. 155-162
Author(s):  
A. F. Sabitov ◽  
I. A. Safina
Keyword(s):  
Dynamic Response ◽  
Spectral Method ◽  
Amplitude Spectrum ◽  
Low Frequency ◽  
Signal Amplitude ◽  
Measuring Instruments ◽  
Frequency Noise ◽  
Frequency Range ◽  
Calculated Amplitude ◽  
Zero Frequency

The spectral method for establishing dynamic response of measuring instruments basically requires determining the amplitude spectrum of the signal in its informative part that includes the amplitude spectrum at zero frequency. The operating frequency range of existing low-frequency spectrum analyzers is above zero frequency that leads to an uncertainty in dynamic response of measuring instruments determined by the spectral method. The purpose of this paper is to develop a program for calculating the signal amplitude spectrum, starting from zero frequency, to implement a spectral method for determining the dynamic response of measuring instruments on computers equipped with the MatLab package.To implement the spectral method for determining the dynamic response of measuring instruments, we developed a program in the MatLab 2013b environment that determines the signal amplitude spectrum from zero Hertz. The program reads the source data from Excel tables and presents the calculated amplitude spectrum as a chart and a report table.It is shown that the developed program calculates the signal amplitude spectrum with a standard deviation of not more than 3.4 % in the frequency range of 0 to 10 rad/s. The calculated amplitude spectrum allows determining the time constant of first-order aperiodic measuring instruments with an uncertainty of not more than 0.166 % at any noise level, if their frequencies are outside the information part of the spectrum.We demonstrated the claimed advantage of the spectral method for determining dynamic response using the developed program by the example of a high-frequency noise in the transient response of some measuring instruments.

scholarly journals Asymptotics of eigenfrequencies in the dynamic response of elongated multi-structures

2011 ◽  
Vol 468 (2138) ◽  
pp. 378-394 ◽  
Author(s):  
M. Brun ◽  
G. F. Giaccu ◽  
A. B. Movchan ◽  
N. V. Movchan
Keyword(s):  
Dynamic Response ◽  
Elastic System ◽  
Low Frequency ◽  
Design Tool ◽  
Asymptotic Estimates ◽  
Bridge Structure ◽  
Frequency Range ◽  
Floquet Waves ◽  
Asymptotic Optimization ◽  
Analytical Formulae

The paper addresses a mathematical model describing the dynamic response of an elongated bridge supported by elastic pillars. The elastic system is considered as a multi-structure involving subdomains of different limit dimensions connected via junction regions. Analytical formulae have been derived to estimate eigenfrequencies in the low frequency range. The analytical findings for Bloch–Floquet waves in an infinite periodic structure are compared with the finite element numerical computations for an actual bridge structure of finite length. The asymptotic estimates obtained here have also been used as a design tool in problems of asymptotic optimization.

SEA Subsystem Property Identification by Periodic FEM Approach

2011 ◽  
Vol 94-96 ◽  
pp. 1979-1982
Author(s):  
Jie Gao ◽  
Ke An Chen
Keyword(s):  
Dynamic Response ◽  
High Frequency ◽  
Periodic Structures ◽  
Low Frequency ◽  
Engineering Method ◽  
Complex Structures ◽  
High Frequency Range ◽  
Frequency Range ◽  
Remarkable Improvement ◽  
Property Identification

A study on SEA properties of periodically stiffened structure was accomplished based on the periodic theory. With application of certain software, a simulation was performed on a common periodically stiffened fuselage structure. The results indicate such modeling approach reflects relatively accurate property of subsystem in mid and high frequency range, while a remarkable improvement could also be expected in low frequency range, especially for complex structures. Such approach was approved as one reliable engineering method for solving dynamic response of periodic structures.

Simplified Model for ASM Dynamics

2011 ◽  
Author(s):  
A. M. Al-Jumaily ◽  
Y. Du
Keyword(s):  
Dynamic Response ◽  
Finite Length ◽  
Smooth Muscles ◽  
Low Frequency ◽  
Length Change ◽  
Simplified Model ◽  
Frequency Range ◽  
Cycling Rate ◽  
Cross Bridge ◽  
Length Changes

The dynamic response of contracted airway smooth muscles to a finite length change and longitudinal oscillations is described using a simplified model. The model is intended to interpret the biophysical events but not to accurately describe them. It shows that the value of tissue length changes have pronounced indications of cross-bridge detachment. However, the frequency of oscillations represents the velocity of the length change, which affects the cross-bridge cycling rate reflected in the low frequency range.

Development of Mathematical Models for Evaluating Child Occupant Impact Dynamics and Intrusions of the Vehicle Structure

2008 ◽  
Author(s):  
Ahmed M. Elmarakbi
Keyword(s):  
Dynamic Response ◽  
Mathematical Models ◽  
Seat Belt ◽  
Vehicle Body ◽  
Design Stage ◽  
Injury Criteria ◽  
Front End ◽  
Vehicle Structure ◽  
Lumped Masses ◽  
Child Occupant

Two mathematical models are developed and analyzed in this paper to predict the dynamic response in vehicle crashes. The first model is developed to capture the front-end intrusion of the vehicle structure in frontal collision. The second model is proposed to define the interaction between the child occupant and vehicle passenger compartment and to predict the acceleration injuries during a sudden impulse load. In these mathematical models, the bumper and vehicle body are defined by lumped masses and longitudinal rails of the front-end structure are defined by plastic springs. Moreover, the child occupants are considered as lumped masses, connected to the child seat and vehicle body masses by means of restraint systems. The occupant restraint characteristics of seat belt are represented by stiffness and damping elements. To obtain the dynamic response of the occupant, the equations of motion of the vehicle impact system in both full and offset scenarios are developed and analytically solved using Incremental Harmonic Balance Method (IHBM). The injury criteria, child’s acceleration and vehicle’s font-end deformation, are used to interpret the results. It is demonstrated from the simulations that the dynamic response and injury criteria are easily captured and analyzed. It is also shown that the mathematical models are flexible, useful in optimization studies and it can be used at initial design stage.

scholarly journals Vibration Isolation of a Rubber-Concrete Alternating Superposition In-Filled Trench for Train-Induced Environmental Vibration Based on 2.5D Indirect Boundary Element Method

2021 ◽  
Vol 9 ◽  
Author(s):  
Liguo Jin ◽  
Jingya Wang ◽  
Xujin Liu ◽  
Qiangqiang Li ◽  
Zhenghua Zhou
Keyword(s):  
Elastic Waves ◽  
High Speed ◽  
Vibration Isolation ◽  
Soft Soil ◽  
Low Frequency ◽  
Isolation Effect ◽  
High Speed Train ◽  
Frequency Range ◽  
The Impact ◽  
Rubber Concrete

A new train-induced vibration isolation measure of rubber-concrete alternating superposition in-filled trench is presented in this paper. For analyzing the vibration isolation effect of the new measure, this paper establishes a 2.5D train-track-layered foundation-filled trench model to analyze the dynamics of track and layered foundation with the in-filled trench. The correctness of the model is verified by using the measured data of the Sweden X-2000 high-speed train. The vibration isolation effect of the rubber-concrete alternating superposition in-filled trench is calculated by using the actual soft soil foundation parameters of the X-2000 high-speed train, and the vibration isolation effect is also compared with that of the empty trench, rubber in-filled trench, and concrete in-filled trench. The results show that the vibration isolation effect of the rubber-concrete alternating superposition in-filled trench proposed in this paper is better than that of the C30 concrete in-filled trench, especially the impact on displacement. Compared with low-frequency vibrations generated by the lower train speed, the rubber-concrete alternating superposition in-filled trench has a better vibration isolation effect on high-frequency vibrations caused by higher-speed trains. The rubber-concrete alternately superposition in-filled trench has the frequency band characteristics of elastic waves. Elastic waves in the passband frequency range can propagate without attenuation, while the elastic waves in the forbidden frequency range will be filtered out.

Seismic Interaction between a Lined Tunnel and a Hill under Plane SV Waves by IBEM

2019 ◽  
Vol 19 (02) ◽  
pp. 1950004 ◽  
Author(s):  
Zhongxian Liu ◽  
Hai Zhang ◽  
Alexander Cheng ◽  
Chengqing Wu ◽  
Guogang Yang
Keyword(s):  
Dynamic Response ◽  
Low Frequency ◽  
Radiation Condition ◽  
Dynamic Interaction ◽  
Frequency Range ◽  
Seismic Safety ◽  
Reflected Waves ◽  
Diffracted Waves ◽  
Plane Sv Waves ◽  
The Hill

This paper investigates the dynamic interaction between a lined tunnel and a hill under plane SV waves using the indirect boundary element method (IBEM), with the displacement and stress characteristics of the system presented in frequency domain. The IBEM has several unique advantages such as reducing calculation dimension, automatically satisfying the infinite radiation condition, etc. The numerical results indicated that the dynamic response of the tunnel–hill system is strongly dependent on incident wave characteristics, geometrical and material properties of the lined tunnel, as well as the topography of the hill. For a dimension ratio between the hill and tunnel of less than 10.0, the lined tunnel has large amplification or deamplification effect on the dynamic response of the hill. Correspondingly, the hill also greatly amplifies the displacement and stress concentration of the tunnel especially in the lower-frequency range, due to the complicated interference effect among the reflected waves and diffracted waves induced by the tunnel and hill. Also demonstrated is that the displacement and stress amplitude spectrums highly depend on the incident frequency and the space location, and there exist multiple peaks and troughs in the spectrum curve with the peaks usually appearing in the low-frequency range. Thus, for the seismic safety assessment of a hill slope or hill tunnel in practice, the dynamic interaction within the tunnel–hill system should be taken into consideration.

Evaluation of Special Hearing Aids for Deaf Children

1971 ◽  
Vol 36 (4) ◽  
pp. 527-537 ◽  
Author(s):  
Norman P. Erber
Keyword(s):  
Hearing Aids ◽  
High Frequency ◽  
Hearing Aid ◽  
Low Frequency ◽  
Acoustic Stimulation ◽  
Deaf Children ◽  
Frequency Range ◽  
Frequency Limit ◽  
Unpublished Studies ◽  
Published Research

Two types of special hearing aid have been developed recently to improve the reception of speech by profoundly deaf children. In a different way, each special system provides greater low-frequency acoustic stimulation to deaf ears than does a conventional hearing aid. One of the devices extends the low-frequency limit of amplification; the other shifts high-frequency energy to a lower frequency range. In general, previous evaluations of these special hearing aids have obtained inconsistent or inconclusive results. This paper reviews most of the published research on the use of special hearing aids by deaf children, summarizes several unpublished studies, and suggests a set of guidelines for future evaluations of special and conventional amplification systems.

Dynamic Damping and Stiffness Characteristics of the Rolling Tire

2001 ◽  
Vol 29 (4) ◽  
pp. 258-268 ◽  
Author(s):  
G. Jianmin ◽  
R. Gall ◽  
W. Zuomin
Keyword(s):  
Dynamic Behavior ◽  
Variable Parameter ◽  
Low Frequency ◽  
Vertical Load ◽  
Frequency Range ◽  
Inflation Pressure ◽  
Vehicle Simulation ◽  
Dynamic Damping ◽  
Speed Range ◽  
Stiffness Characteristics

Abstract A variable parameter model to study dynamic tire responses is presented. A modified device to measure terrain roughness is used to measure dynamic damping and stiffness characteristics of rolling tires. The device was used to examine the dynamic behavior of a tire in the speed range from 0 to 10 km/h. The inflation pressure during the tests was adjusted to 160, 240, and 320 kPa. The vertical load was 5.2 kN. The results indicate that the damping and stiffness decrease with velocity. Regression formulas for the non-linear experimental damping and stiffness are obtained. These results can be used as input parameters for vehicle simulation to evaluate the vehicle's driving and comfort performance in the medium-low frequency range (0–100 Hz). This way it can be important for tire design and the forecasting of the dynamic behavior of tires.

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