A new methodology for the estimation of wheel–rail contact forces at a high-frequency range

2018 ◽  
Vol 232 (10) ◽  
pp. 2353-2370 ◽  
Author(s):  
Vahid R Bagheri ◽  
Davood Younesian ◽  
Parisa H Tehrani
Keyword(s):  
High Speed ◽  
Radial Strain ◽  
Element Model ◽  
Contact Forces ◽  
Least Square ◽  
Characteristic Matrix ◽  
Rotating Speed ◽  
Ill Posed ◽  
Rolling Wheel ◽  
Rotating Load

Online measurement of wheel–rail contact forces is nowadays in demand for evaluating safety and manoeuvring the condition in real time and in real operation. In this study, the wheel–rail contact forces are estimated using a novel indirect identification method based on the measured radial strain on the wheel web. Further, the strain response of the rolling wheel is derived using an analytical solution of the disk under a rotating load, and a scheme was prepared for the identification of the rolling wheel parameters and its corresponding characteristic matrix. An appropriate angular strain configuration is employed to eliminate the effect of wheel rotation. The Tikhonov regularization technique is employed to solve the ill-posed least square problem and to attenuate the effect of noisy measurement and numerical uncertainty during the estimation of the forces. A finite element model of the rotating load is then constructed to investigate the effectiveness and accuracy of the proposed methodology. The effects of the rotating speed, loading and measurement noise on the estimated normal force are studied. It is found that neglecting the effect of the rotating speed causes a notable error particularly in the high-speed range.

scholarly journals The High-Speed Train Seat Design Based on the Human Lumbar Biomechanical Analysis

2014 ◽  
Vol 6 ◽  
pp. 524802
Author(s):  
Yunpeng Guo ◽  
Guiqiu Song
Keyword(s):  
High Speed ◽  
Element Model ◽  
Least Square ◽  
Biomechanical Analysis ◽  
High Speed Train ◽  
Design Standards ◽  
Engineering Technology ◽  
Moving Least Square ◽  
Physical Ergonomics ◽  
The Finite Element Model

This paper, aimed at the problems of high-speed train seat design standards that lack biomechanical analysis, analyzed the lumbar force of sitting position and verified the validity of the finite element model of human lumbar L1–L5 that had been built by reverse engineering technology. Based on the lumbar force distribution, the methods of exterior penalty and moving least square were adopted to establish a high-speed train seat equation that caters for physical ergonomics and a new high-speed train seat model was designed so as to improve the comfort for passengers.

scholarly journals Prediction of railway induced ground vibration through multibody and finite element modelling

2013 ◽  
Vol 4 (1) ◽  
pp. 167-183 ◽  
Author(s):  
G. Kouroussis ◽  
O. Verlinden
Keyword(s):  
Finite Element ◽  
High Speed ◽  
Vertical Plane ◽  
Time History ◽  
Ground Vibration ◽  
Element Model ◽  
Contact Forces ◽  
Railway Transportation ◽  
Lumped Mass ◽  
Mass Model

Abstract. The multibody approach is now recognized as a reliable and mature computer aided engineering tool. Namely, it is commonly used in industry for the design of road or railway vehicles. The paper presents a framework developed for predicting the vibrations induced by railway transportation. Firstly, the vehicle/track subsystem is simulated, on the basis of the home-made C++ library EasyDyn, by mixing the multibody model of the vehicle and the finite element model of the track, coupled to each other through the wheel/rail contact forces. Only the motion in the vertical plane is considered, assuming a total symmetry between left and right rails. This first step produces the time history of the forces exerted by the ballast on the foundation, which are then applied to a full 3-D FEM model of the soil, defined under the commercial software ABAQUS. The paper points out the contribution of the pitch motion of the bogies and carbodies which were neglected in previous publications, as well as the interest of the so-called coupled-lumped mass model (CLM) to represent the influence of the foundation in the track model. The potentialities of the model are illustrated on the example of the Thalys high-speed train, riding at 300 km h−1 on the Belgian site of Mévergnies.

Stability of High Speed Milling Based on Instantaneous Cutting Force

2012 ◽  
Vol 152-154 ◽  
pp. 404-408
Author(s):  
Hong Liang Zhou ◽  
Wei Xiao Tang ◽  
Qing Hua Song
Keyword(s):  
Cutting Force ◽  
High Speed ◽  
End Milling ◽  
Element Model ◽  
Face Milling ◽  
Force Model ◽  
Dynamics Model ◽  
High Speed Milling ◽  
High Productivity ◽  
Rotating Speed

High-speed milling (HSM) has advantages in high productivity high precision and low production cost. Thus it can be widely used in the manufacture industry. However, when the speed of spindle-tool reaches a higher speed range, the gyroscopic effect will become an important part of its stable milling. In this paper, a dynamics model of HSM system was proposed considering the influence of gyroscopic moment due to high rotating speed of end milling. Finite element model (FEM) is used to model the dynamics of a spindle-milling system. It obtains the trajectory of central point in face milling with considering gyroscopic effects through the dynamics model at high speeds. Then the cutting force model will be corrected by the trajectory of face milling. Then the stability lobes diagrams (SLD) was elaborated. Cutting thickness effects have non-negligible impact on stability limitation.

scholarly journals Model Updating and Structural Optimization of Circular Saw Blades with Internal Slots

2014 ◽  
Vol 6 ◽  
pp. 546496
Author(s):  
Wei-Hsin Gau ◽  
Kun-Nan Chen ◽  
Yunn-Lin Hwang
Keyword(s):  
Finite Element ◽  
High Speed ◽  
Structural Integrity ◽  
Model Updating ◽  
Element Model ◽  
Frequency Separation ◽  
Element Analysis ◽  
Sizing Optimization ◽  
Rotating Speed ◽  
Circular Saw

Circular diamond saws rotating in high speed are widely used to cut hard materials, and narrow slots on saw blades are sometimes used to reduce the blades' vibration and noise. Sizing optimization of the internal, annular slots on saw blades is investigated in this paper. First, an accurate finite element model representing an actual saw blade is obtained by model updating. Then, sizing optimization on two types of annular slots is performed to maximize the frequency separation between the finite element analysis results and the saw blade's operational speed and to reduce the possibility of structural resonance. Optimization results demonstrate great improvements in frequency separation from the rotating speed of 500 Hz for the optimized models, and stress analyses on the optimized blade models confirm the structural integrity of the designs.

Optimization of Circular Diamond Saw Blades with Annular Slots

2013 ◽  
Vol 479-480 ◽  
pp. 289-293
Author(s):  
Wei Hsin Gau ◽  
Kun Nan Chen ◽  
Yunn Lin Hwang
Keyword(s):  
Finite Element ◽  
High Speed ◽  
Model Updating ◽  
Element Model ◽  
Frequency Separation ◽  
Element Analysis ◽  
Sizing Optimization ◽  
Rotating Speed ◽  
Diamond Saw ◽  
Saw Blade

Circular diamond saws rotating in high speed are widely used to cut hard materials, and narrow slots on saw blades are sometimes used to reduce the blades vibration and noise. Sizing optimization of the annular slots on saw blades is investigated in this paper. First, an accurate finite element model representing an actual saw blade is obtained by model updating. Then, sizing optimization on two types of annular slots is performed to maximize the frequency separation between the finite element analysis results and the saw blades operational speed, and to reduce the possibility of structural resonance. Optimization results demonstrate great improvements in frequency separation from the rotating speed of 500 Hz for the optimized models.

scholarly journals Study on Steady-State Responses of High-Speed Vehicle Using Infinite Long Track Model

2020 ◽  
Vol 2020 ◽  
pp. 1-17
Author(s):  
Wubin Cai ◽  
Maoru Chi
Keyword(s):  
Steady State ◽  
High Speed ◽  
Resonance Region ◽  
Contact Forces ◽  
Least Square ◽  
High Speed Rail ◽  
Window Method ◽  
Steady State Responses ◽  
State Responses ◽  
High Speed Vehicle

The coupled vehicle/track dynamic model is formulated through integrating a high-speed rail vehicle model with a slab track model via the wheel/rail contact model. The sliding window method is improved using the least square criterion to simulate the vehicle travelling along the infinite long track. The steady-state responses of a high-speed vehicle induced by the discrete sleepers and slab segments are investigated through numerical simulation and analysis of the experimental results. Also the validity of the coupled vehicle/track model is examined through comparing the simulation results with those acquired from field test measurements. The experimental and numerical results show that the wheel/rail contact forces fluctuate considerably as long as the sleeper passing frequency approaches the frequency of P2 resonance (wheelset and rail bouncing in phase on the slab). Increasing the damping of rail pads and primary suspension can lower the steady-state response amplitudes at the resonance region. The oscillations in the wheel/rail normal forces arising from the discrete slab segment excitation can be reduced by increasing the support stiffness of the CAM (cement asphalt mortar) layer under the slab.

The Blade Strength and the Dynamic Characteristics of High Speed Micro-Turbines

2006 ◽  
Author(s):  
Jao Hwa Kuang ◽  
Hsuan-Sheng Chen ◽  
Tsung-Pin Hung
Keyword(s):  
Finite Element ◽  
Stainless Steel ◽  
High Speed ◽  
Natural Frequencies ◽  
Operating Temperature ◽  
Element Model ◽  
Ti Alloy ◽  
Rotating Speed ◽  
Mechanical Creep ◽  
Micro Turbine

The effects of centrifugal force and operating temperature on the stress and creep deformation of rotating micro-turbo rotors are studied in this work. The thermal-mechanical- creep coupled finite element model provided in the MARC package is employed. The variation of stresses and creep strain distributions in turbo blades made of different materials, e.g. stainless steel (A304L), Ti-alloy (Ti-2411) and two ceramics (SiC and SiN3) are analyzed and compared. The effect of rotating speed on the natural frequencies of the micro-turbine with different turbo-blade materials are also evaluated and compared in this study. Numerical results indicate that the strength and dynamic behavior of the micro-turbo rotor is very sensitive to the material of turbo blade.

Modeling of Tread Block Contact Mechanics Using Linear Viscoelastic Theory3

2008 ◽  
Vol 36 (3) ◽  
pp. 211-226 ◽  
Author(s):  
F. Liu ◽  
M. P. F. Sutcliffe ◽  
W. R. Graham
Keyword(s):  
High Speed ◽  
Slip Rate ◽  
Material Model ◽  
Contact Forces ◽  
Block Modeling ◽  
Rate Dependent ◽  
Linear Viscoelastic Material ◽  
Linear Viscoelastic ◽  
The Impact ◽  
Good Agreement

Abstract In an effort to understand the dynamic hub forces on road vehicles, an advanced free-rolling tire-model is being developed in which the tread blocks and tire belt are modeled separately. This paper presents the interim results for the tread block modeling. The finite element code ABAQUS/Explicit is used to predict the contact forces on the tread blocks based on a linear viscoelastic material model. Special attention is paid to investigating the forces on the tread blocks during the impact and release motions. A pressure and slip-rate-dependent frictional law is applied in the analysis. A simplified numerical model is also proposed where the tread blocks are discretized into linear viscoelastic spring elements. The results from both models are validated via experiments in a high-speed rolling test rig and found to be in good agreement.

Modeling Vibration-Induced Tire-Pavement Interaction Noise in the Mid-frequency Range

2020 ◽  
Author(s):  
Sterling McBride ◽  
Ricardo Burdisso ◽  
Corina Sandu
Keyword(s):  
Sound Intensity ◽  
Element Model ◽  
Dominant Frequency ◽  
Contact Forces ◽  
Surface Velocity ◽  
New Wave ◽  
Normal Surface ◽  
Radiated Noise ◽  
Physical Effects ◽  
Effects Of Rotation

ABSTRACT Tire-pavement interaction noise (TPIN) is one of the main sources of exterior noise produced by vehicles traveling at greater than 50 kph. The dominant frequency content is typically within 500–1500 Hz. Structural tire vibrations are among the principal TPIN mechanisms. In this work, the structure of the tire is modeled and a new wave propagation solution to find its response is proposed. Multiple physical effects are accounted for in the formulation. In an effort to analyze the effects of curvature, a flat plate and a cylindrical shell model are presented. Orthotropic and nonuniform structural properties along the tire's transversal direction are included to account for differences between its sidewalls and belt. Finally, the effects of rotation and inflation pressure are also included in the formulation. Modeled frequency response functions are analyzed and validated. In addition, a new frequency-domain formulation is presented for the computation of input tread pattern contact forces. Finally, the rolling tire's normal surface velocity response is coupled with a boundary element model to demonstrate the radiated noise at the leading and trailing edge locations. These results are then compared with experimental data measured with an on-board sound intensity system.

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