A Longitudinal Force Model for Multibody Railroad Vehicle System Applications

2005 ◽  
Author(s):  
Quan Meng ◽  
Jason R. Heineman ◽  
Ahmed A. Shabana
Keyword(s):  
Time Derivative ◽  
Rolling Resistance ◽  
Longitudinal Force ◽  
Force Model ◽  
Arc Length ◽  
Track Geometry ◽  
Velocity Transformation ◽  
Draft Gear ◽  
Angular Velocities ◽  
Air Brake System

In this paper, a model is developed to analyze the longitudinal forces of interaction between the vehicles within a train consist. The track geometry is described in a preprocessor in terms of an arc length parameter. A single degree of freedom vehicle model is developed, in which the nonlinear equation of motion of the vehicle is expressed in terms of the track arc length using a velocity transformation. The velocity transformation matrix is obtained by expressing the Cartesian and angular velocities in terms of the time derivative of the arc length. Models are developed for representing; braking forces from a typical air brake system, coupler reactions from draft gear or end-of-car cushioning devices, and the rolling resistance acting on each vehicle. An example of a 10-car train is used to demonstrate the use of the formulations presented in this paper. Different simulation scenarios, including varying track configurations and brake failure, are presented.

Railway track longitudinal force model

2019 ◽  
Vol 59 (1) ◽  
pp. 155-170 ◽  
Author(s):  
Qing Wu ◽  
Yan Sun ◽  
Maksym Spiryagin ◽  
Colin Cole
Keyword(s):  
Longitudinal Force ◽  
Railway Track ◽  
Force Model

Validation of a High-Fidelity Finite Element Tire Model on Pavement

2020 ◽  
Author(s):  
Tamer Wasfy ◽  
Hatem Wasfy ◽  
Paramsothy Jayakumar ◽  
Srinivas Sanikommu
Keyword(s):  
Finite Element ◽  
Normal Load ◽  
Rolling Resistance ◽  
Lateral Force ◽  
Longitudinal Force ◽  
Friction Model ◽  
Rubber Matrix ◽  
Slip Angle ◽  
High Fidelity ◽  
Tire Model

Abstract The objective of this study is to validate a high-fidelity finite element tire model on hard pavement. In this model, the tire rubber matrix is modeled using locking-free brick elements with embedded thin beam elements along the tire’s circumference, meridian, and diagonals for modeling the tire’s reinforcements (belt, ply and bead). The internal air pressure is applied as a distributed force on the inner surface of the brick elements. Frictional contact between the outer surface of the brick elements and the pavement is modeled using the penalty method along with an asperity based Coulomb friction model. In order to validate the tire model, a medium duty truck tire is modeled and the following response quantities are compared to experimental results: (1) normal load versus deflection at different tire pressures; (2) rolling resistance versus speed; (3) longitudinal force versus slip; (4) lateral force versus slip angle for different normal loads; and (5) self-aligning torque versus slip angle for different normal loads.

scholarly journals Discrete Element Simulation of Factors Affecting the Fluidity of Nylon Powder

2019 ◽  
Vol 2019 ◽  
pp. 1-10
Author(s):  
Shengqiang Jiang ◽  
Chunyan Duan ◽  
Yixuan Ye ◽  
Chao Tang ◽  
Xiaodong Chen
Keyword(s):  
Particle Size ◽  
Uniform Distribution ◽  
Gaussian Distribution ◽  
Rolling Resistance ◽  
Discrete Element ◽  
Contact Model ◽  
Angle Of Repose ◽  
Force Model ◽  
Factors Affecting ◽  
Powder Particles

Powder fluidity is one of the important factors affecting the smoothness of selective laser sintered parts and the mechanical properties of sintered parts. In this paper, the angle of repose (AOR) and angle of internal friction of nylon PA3200 powder were measured by a powder comprehensive tester and a direct shear tester to evaluate the flow properties of the powder particles. Based on the discrete element method (DEM), the rolling resistance contact model and the van der Waals force model were used to describe the interaction forces between the powder particles. The rolling resistance coefficient and friction coefficient within the contact model were calibrated by the results of the AOR experiments. Based on the orthogonal experimental method, the particle size and particle size distribution (PSD) (such as uniform distribution and Gaussian distribution) were selected as the influencing factors, and the effect of particle size and PSD on the fluidity of nylon PA3200 powder was studied by numerical simulation. The results show that the PSD has a stronger influence on the AOR than particle size, and the fluidity of uniform distribution is better than that of the Gaussian distribution.

scholarly journals A new arc-length control method based on the rates of the internal and the dissipated energy

2016 ◽  
Vol 33 (1) ◽  
pp. 100-115 ◽  
Author(s):  
Stefan May ◽  
Julien Vignollet ◽  
René de Borst
Keyword(s):  
Control Method ◽  
Time Derivative ◽  
Phase Field Model ◽  
Second Law Of Thermodynamics ◽  
Dissipated Energy ◽  
Control Procedure ◽  
Arc Length ◽  
Interface Elements ◽  
Content Type ◽  
Two Parameters

Purpose – The purpose of this paper is to introduce a new arc-length control method for physically non-linear problems based on the rates of the internal and the dissipated energy. Design/methodology/approach – In this paper, the authors derive from the second law of thermodynamics the arc-length method based on the rate of the dissipated energy and from the time derivative of the energy density the arc-length method based on the rate of the internal energy. Findings – The method requires only two parameters and can automatically trace equilibrium paths which display multiple snap-through and/or snap-back phenomena. Originality/value – A fully energy-based control procedure is developed, which facilitates switching between dissipative and non-dissipative arc-length control equations in a natural way. The method is applied to a plate with an eccentric hole using the phase field model for brittle fracture and to a perforated beam using interface elements with decohesion.

Train Energy and Dynamics Simulator (TEDS): A State-of-the-Art Longitudinal Train Dynamics Simulator

2012 ◽  
Author(s):  
David R. Andersen ◽  
Graydon F. Booth ◽  
Anand R. Vithani ◽  
Som P. Singh ◽  
Anand Prabhakaran ◽  
...  
Keyword(s):  
Fluid Dynamic ◽  
Simulation Software ◽  
System Level ◽  
Test Results ◽  
Dynamic Representation ◽  
Draft Gear ◽  
Train Dynamics ◽  
Air Brake System ◽  
And Performance ◽  
Dynamic Braking

Train safety and operational efficiency are enhanced by the ability to understand the behavior of trains under varying conditions. Under the direction of the Federal Railroad Administration (FRA), a longitudinal train dynamics and operation simulation software — Train Energy and Dynamics Simulator (TEDS) — has been developed. TEDS is capable of modeling modern train operations and equipment, and is an effective tool for studying train operations safety and performance as affected by equipment, train makeup, train handling, track conditions, operating practices and environmental conditions. TEDS simulates the dynamics of longitudinal train action and incorporates the dynamic effects of various different types of draft gears and end-of-car cushioning units including mismatched devices coupled together, the transient response of locomotive tractive and dynamic braking effort, as well as a fluid dynamic representation of the air brake system with the capability to model conventional pneumatic and ECP brake systems. The capabilities of TEDS are described and demonstrated with several examples. The validation effort undertaken is described at both the component and system level. Comparisons of TEDS simulations of impact tests with the test results are shown to verify the draft gear and end-of-car cushioning unit models. The air brake model predictions are verified by comparing brake rack test results to TEDS simulations of braking behavior.

scholarly journals Force Model for Complex Profile Tool in Broaching Inconel 718

2021 ◽  
Author(s):  
Jing Ni ◽  
Kangcheng Tong ◽  
Zhen Meng ◽  
Kai Feng
Keyword(s):  
Shear Zone ◽  
Fem Simulation ◽  
Projection Area ◽  
Force Model ◽  
Arc Length ◽  
Complex Profile ◽  
Modified Model ◽  
Aero Engines ◽  
Complex Parts ◽  
Direction Model

Abstract Complex profile broaches are widely used in the manufacture of complex parts of aero-engines, but their cutting forces in the broaching process are difficult to predict and control. A new numerical model for broaching force with complex profile tools is presented, which considers the area and arc length of curved shear zone projection. The area and arc length were calculated by the curve function of the projection plane, which is firstly predicted by FEM simulation. Compared with the conventional force model, the accuracy of the modified model has been moderately improved. Ultimately, the modified main broaching force (Y-direction) model and the modified normal force (Z-direction) model show a significant improvement in accuracy by 4.8% and 9.7%, respectively. It suggests that the projection area of curved shear zone A1 and the projection arc length of curved shear zone l1 have a big impact on the broaching process. Moreover, the modified model proposed in this paper can provide guidance for the design of complex profile tools and facilitate the efficient and high-precision machining of complex parts.

Development of a Human Symbiotic Assist Arm “PAS-Arm” (Design of Mechanism · CVT and Experimental System)

2013 ◽  
Vol 25 (1) ◽  
pp. 211-219 ◽  
Author(s):  
Mineo Higuchi ◽  
Keyword(s):  
Degrees Of Freedom ◽  
Time Derivative ◽  
Three Dimensional ◽  
Experimental System ◽  
Normal Vector ◽  
Physical Interaction ◽  
Differential Relation ◽  
Continuously Variable Transmissions ◽  
Angular Velocities ◽  
The Relationship

We describe a new robotic assist device: a passive assist arm (PAS-Arm). PAS-Arms are intended for direct physical interaction with a human operator, handling a shared payload. PAS-Arms are physically passive. Their purpose is not to enhance human strength, but to provide virtual guiding surfaces, which constrain and guide the motion of the payload within a shared workspace. PAS-Arms have three joints and a three-dimensional workspace, but possess only a two degrees of freedom, due to the reduction of degrees of freedom created by a combination of Continuously Variable Transmissions (CVTs) and differential gears. We have developed an experimental system of the PAS-Arm. In this paper, we describe kinematic specification of the experimental system. We discuss the differential relation of transmission ratios created by the CVTs. We conducted the relationship between transmission ratio resolutions of the CVTs and resolutions of normal vector of the virtual guiding surface, and the relationship between angular velocities of PAS-Arm’s joints and time derivative of the transmission ratios. Assuming that the Euclidean norm of the angular velocities is constant, maximum time derivative of transmission ratios is in proportion to link lengths of the PAS-Arm. We also describe the design of the CVT for use in the experimental system.1 1. This paper is the full translation from the transactions of JSME, Series C, Vol.75, No.749, pp. 104-112, 2009.

scholarly journals Establishment and Verification of the Cutting Grinding Force Model for the Disc Wheel Based on Piezoelectric Sensors

Sensors ◽  
2019 ◽  
Vol 19 (3) ◽  
pp. 725 ◽  
Author(s):  
Jing Ni ◽  
Kai Feng ◽  
M.S.H. Al-Furjan ◽  
Xiaojiao Xu ◽  
Jing Xu
Keyword(s):  
Cutting Force ◽  
Grinding Force ◽  
Piezoelectric Sensors ◽  
Force Model ◽  
Arc Length ◽  
Cutting Force Model ◽  
Grinding Force Model ◽  
Proposed Model ◽  
Experimental Findings ◽  
Contact Arc

In this paper, a new model of cutting grinding force for disc wheels is presented. Initially, it was proposed that the grinding cutting force was formed by the grinding force and cutting force in combination. Considering the single-grit morphology, the single-grit average grinding depth, the effective number of grits, and the contact arc length between the grit and the workpiece comprehensively, the grinding force model and the cutting force model were established, respectively. Then, a universal grinding cutting force model was optimized by introducing the effective grit coefficient model, dependent on the probability statistical method and the grit height coefficient model with Rayleigh’s distribution theory. Finally, according to the different proportions of the grinding force and cutting force, the grinding cutting force model, with multi-particles, was established. Simulation and experimental results based on piezoelectric sensors showed that the proposed model could predict the intermittent grinding cutting force well. Moreover, the inclusion of the grit height coefficient and the effective grits number coefficient improved the modeling accuracy. The error between the simulation and experimental findings in grinding cutting force was reduced to 7.8% in comparison with the traditional model. In addition, the grinding cutting force can be divided into three segments; increasing, steadiness, and decreasing, respectively found through modeling.

Surface Texturing in Micro Parametric Machining

2016 ◽  
Vol 10 (1) ◽  
pp. 30-40
Author(s):  
Takashi Matsumura ◽  
◽  
Yasuharu Hayase ◽  
Jerome Blanchet ◽  
Naoki Iioka ◽  
...  
Keyword(s):  
Surface Structure ◽  
Cutting Tool ◽  
Surface Texturing ◽  
Force Model ◽  
Micro Scale ◽  
Tool Holder ◽  
Rotation Center ◽  
Angular Velocities ◽  
Surface Profiles ◽  
Cutting Direction

Parametric machining is applied to fabricate micro-scale textures on surfaces by rotating the workpiece and tool. Periodic circular textures are controlled by only four parameters: the distance from the rotation center of the workpiece to that of the tool holder, the rotation radius of the tool in the tool holder, and the angular velocities of the workpiece and the tool holder. The textures to be machined are controlled by simulating the trajectory of the tool on the workpiece. A texturing machine was developed with two servomotors and three stepping motors, where the rotations of the servomotors were synchronized. Some examples are shown to verify the presented texturing in cutting tests. Because functional surfaces should be controlled by the surface structure, a model is presented to simulate the surface profiles of the textures. The orientation of the cutting tool with respect to the cutting direction is discussed in terms of the surface structure and the surface finish. The cutting load is estimated with the indentation and the shearing components in a simplified force model.

Kinematic Analysis of Epicyclic Bevel Gear Trains With Matroid Method

2012 ◽  
Vol 134 (11) ◽  
Author(s):  
Ilie Talpasanu ◽  
P. A. Simionescu
Keyword(s):  
Kinematic Analysis ◽  
Degrees Of Freedom ◽  
Time Derivative ◽  
Oriented Graph ◽  
Bevel Gear ◽  
Efficient Computation ◽  
Cycle Basis ◽  
Angular Velocities ◽  
Gear Trains ◽  
Cycle Matroid

The paper presents a novel technique for the kinematic analysis of bevel gear trains using the incidence matrices of an edge-oriented graph of the mechanism. The kinematic equations are then obtained in matrix form using a cycle basis from a cycle matroid. These equations can be systematically generated, and allow for an efficient computation of the angular velocities of the gears and planet carriers of the mechanism without employing time derivative operations. As illustrated in the paper, the method is applicable to bevel gear trains of any number of gears or degrees of freedom.

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