scholarly journals Modeling and Analysis of Vehicle Shimmy with Consideration of the Coupling Effects of Vehicle Body

2019 ◽  
Vol 2019 ◽  
pp. 1-14
Author(s):  
Xiaogao Li ◽  
Ning Zhang ◽  
Xianjian Jin ◽  
Nan Chen
Keyword(s):  
Degrees Of Freedom ◽  
Lagrange Equation ◽  
Dynamic Responses ◽  
Vehicle Body ◽  
Coupling Effects ◽  
Modeling And Analysis ◽  
Front Suspension ◽  
Vehicle Velocity ◽  
Longitudinal Position ◽  
The Relationship

Based on the Lagrange equation, a 9-degrees-of-freedom shimmy model with consideration of the coupling effects between the motions of vehicle body and the shimmy of front wheels and a 5-degrees-of-freedom shimmy model ignoring these coupling effects for a vehicle with double-wishbone independent front suspensions are presented here to study the problem of vehicle shimmy. According to the eigenvalue loci of system’s Jacobian matrix plotted on the complex plane, the Hopf bifurcation characteristics of nonlinear shimmy are studied and the conditions for the generation of limit cycle are analyzed. Numerical calculation and simulation are used to study the dynamic behavior of vehicle shimmy. By comparing the dynamic responses of two different shimmy models, the coupling effects of vehicle body on vehicle shimmy are studied. Finally, the relationship between the amplitude of each DoF and vehicle velocity and the influences of vehicle parameters such as the mass of vehicle body, the longitudinal position of the center of gravity of vehicle body, and the inclination angle of front suspension on shimmy are studied.

Pseudo-rigid-body dynamic modeling and analysis of compliant mechanisms

2017 ◽  
Vol 232 (9) ◽  
pp. 1665-1678 ◽  
Author(s):  
Yue-Qing Yu ◽  
Qian Li ◽  
Qi-Ping Xu
Keyword(s):  
Rigid Body ◽  
Dynamic Model ◽  
Dynamic Modeling ◽  
Dynamic Models ◽  
Compliant Mechanisms ◽  
Lagrange Equation ◽  
Dynamic Responses ◽  
Modeling And Analysis ◽  
Rigid Body Dynamic ◽  
Body Dynamic

An intensive study on the dynamic modeling and analysis of compliant mechanisms is presented in this paper based on the pseudo-rigid-body model. The pseudo-rigid-body dynamic model with single degree-of-freedom is proposed at first and the dynamic equation of the 1R pseudo-rigid-body dynamic model for a flexural beam is presented briefly. The pseudo-rigid-body dynamic models with multi-degrees-of-freedom are then derived in detail. The dynamic equations of the 2R pseudo-rigid-body dynamic model and 3R pseudo-rigid-body dynamic model for the flexural beams are obtained using Lagrange equation. Numerical investigations on the natural frequencies and dynamic responses of the three pseudo-rigid-body dynamic models are made. The effectiveness and superiority of the pseudo-rigid-body dynamic model has been shown by comparing with the finite element analysis method. An example of a compliant parallel-guiding mechanism is presented to investigate the dynamic behavior of the mechanism using the 2R pseudo-rigid-body dynamic model.

Dynamics modeling and analysis of a four-wheel independent motor-drive virtual-track train

2020 ◽  
pp. 146441932096401
Author(s):  
Zhonghui Yin ◽  
Jiye Zhang ◽  
Haiying Lu ◽  
Weihua Zhang
Keyword(s):  
High Speed ◽  
Load Capacity ◽  
Dynamic Performance ◽  
Spatial Dynamics ◽  
Dynamic Responses ◽  
Dynamics Modeling ◽  
Dynamics Model ◽  
Coupling Effects ◽  
Dynamic Interactions ◽  
Modeling And Analysis

Due to urbanisation and the economic challenges of traffic, it is urgently necessary to develop an environmentally friendly virtual-track train with suitable speed, high load capacity and low construction cost in China. To guide the design and evaluate this train’s dynamic behaviour, a spatial-dynamics model has been developed based on the dynamics theory and tyre-road interaction. The proposed dynamics model comprises mechanical vehicle systems, traction and braking characteristics and tyre-road dynamic interactions. The coupling effects amongst those systems of virtual track train are derived theoretically for the first time. The nonlinear characteristics of the tyre are modelled by the transit tyre-magic formula with consideration of road irregularities. Based on a designed PID controller and the comprehensive dynamics model, the dynamic performance of the system can be revealed considering motion coupling effects and complicated excitations, especially under traction and braking conditions. The dynamic responses of whole virtual track train can be obtained by numerical integration under different conditions. The vibration characteristics of such train are assessed under running at a constant speed and during the traction/braking process. The results show that the vibrations of the vehicle system are significantly influenced by road irregularities, especially at high speed ranges. The motions and vibrations of different components are intensive coupled, which should not to be neglected in the dynamics assessment of the virtual track train. Besides, the dynamics model can also be applied to dynamics-related assessment (fatigue, strength and some damage conditions, et al.) and parameter optimisation of the virtual-track train.

Design and Assessment of a Flexure-Based 2-DOF Micromanipulator for Automatic Cell Micro-Injection

2012 ◽  
Vol 457-458 ◽  
pp. 445-448 ◽  
Author(s):  
Hui Tang ◽  
Yang Min Li ◽  
Ji Ming Huang ◽  
Qin Min Yang
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Theoretical Analysis ◽  
Degrees Of Freedom ◽  
Lagrange Equation ◽  
Element Analysis ◽  
Compliance Matrix ◽  
Cell Injection ◽  
Modeling And Analysis ◽  
Compliance Matrix Method

The design and assessment of a flexure-based parallel micromanipulator with two-degrees-of-freedom (2-DOF) for automatic cell injection is presented in this paper. The design and modeling of the micromanipulator are conducted by employing compliance matrix method. The dynamic modeling and analysis via Lagrange equation are conducted to improve the bandwidth of the mechanism. Both theoretical analysis and finite element analysis (FEA) results well validate the good performance of the micromanipulator which will be applied to practical cell manipulations.

Enhancement of vehicle handling characteristics by suspension kinematic control

2001 ◽  
Vol 215 (2) ◽  
pp. 197-216 ◽  
Author(s):  
S H Lee ◽  
U K Lee ◽  
C S Han
Keyword(s):  
Degrees Of Freedom ◽  
Ride Comfort ◽  
Lateral Acceleration ◽  
Vehicle Body ◽  
Control Input ◽  
Vehicle Handling ◽  
Kinematic Control ◽  
Front Suspension ◽  
Handling Characteristics ◽  
Suspension Geometry

In this paper, the enhancement of vehicle handling characteristics through the active kinematic control system (AKCS) is investigated. AKCS can improve the stability and ride comfort of a vehicle by automatically controlling suspension geometry in accordance with the running conditions of a vehicle. The variable roll centre suspension concept in a McPherson strut suspension is proposed, and lateral acceleration feedback control is derived to calculate the control input. The independent rear wheel steering system, which controls both rear wheels independently and actively, is also proposed. To achieve this, three suggested positions for controlling the suspension geometry are considered. The first position is between the mounting point of the lower arm of a McPherson front suspension and the vehicle body. The second position is between the mounting point of the strut and the vehicle body. The third position is between the mounting point of the lateral link of the multilink rear suspension and the vehicle body. In order to evaluate the handling performance, a 15 degrees of freedom full vehicle model is constructed using the commercial multibody analysis program ADAMS. The control inputs for integrated control of the front and rear suspensions are defined, and roll centre migration and vehicle behaviour are investigated. In step steering and double lane change manoeuvres, the simulation results demonstrate that integrated kinematic control can adjust the roll centre migration, by which the handling characteristics of the AKCS vehicle such as roll angle, lateral acceleration and yaw rate are much improved.

ANSYS-Based Spatial Coupled Vibration Analysis Method of Vehicle-Bridge Interaction System

2013 ◽  
Vol 574 ◽  
pp. 117-126 ◽  
Author(s):  
Xin Yi Huang ◽  
Wei Dong Zhuo ◽  
Guan Ping Shang
Keyword(s):  
Vibration Analysis ◽  
Degrees Of Freedom ◽  
Dynamic Properties ◽  
Lagrange Equation ◽  
Dynamic Responses ◽  
Test Analysis ◽  
Box Girder ◽  
Contact Points ◽  
Concrete Box Girder ◽  
Concrete Box Girder Bridges

An ANSYS-based spatial approach of analysis is proposed for the bridge-vehicle interaction to investigate the dynamic responses of a curved concrete box girder bridge and vehicles. The governing equations of a vehicle model with twelve-degrees-of-freedom (12DOF) are derived from the energy method using the Lagrange equation of motion. Both the bridge and the vehicle system are discretized adopting element type BEAM44, MASS21 and COMBIN14 in the ANSYS program. The interaction forces between the vehicle and bridge are deduced considering the road surface roughness and its velocity term based on the compatibility conditions of the contact points, and detailed formula are presented. The separate iterative algorithm is developed to solve the vehicle-bridge interaction problem. A three-axle cargo truck and a dual-cell box girder curved overpass bridge are chosen for both numerical and field test analysis. The dynamic properties and the dynamic responses of the bridge are both obtained from the numerical and experiment way, and the results agree well with each other by comparison. Its indicated that the procedures presented in this paper can be taken for the further vibration analysis study of curved concrete box girder bridges.

DYNAMIC MODELING AND ANALYSIS OF MULTI-STAGE PLANETARY GEARS COUPLED WITH CENTRAL BEARINGS AND HOUSING

2016 ◽  
Vol 40 (5) ◽  
pp. 1007-1018 ◽  
Author(s):  
Zheng-Ming Xiao ◽  
Xing Wu ◽  
Qing Chen
Keyword(s):  
Degrees Of Freedom ◽  
Lagrange Equation ◽  
Central Component ◽  
Parameter Method ◽  
Planetary Gears ◽  
Modeling And Analysis ◽  
Multi Stage ◽  
Lumped Parameter ◽  
Set Up ◽  
Mesh Phasing

This paper proposes a coupling dynamic model for multi-stage planetary gears train (PGT) based on the gearing theory and Lagrange equation, which is developed by analyzing the displacement relationships of gearing system and the influence of floating components. The time-varying mesh stiffness, bearings in housing, and the torsional support stiffness of ring gears are also considered. This model has 26 degrees-of-freedom (DOF) and adopts three planar DOFs for each central component, mesh phasing relations among planetary gears, and the rotational DOF for the planets of each stage. The modified transverse-torsional model is established in the rotating Cartesian coordinates by using the lumped-parameter method; thus this model is more accurate than the purely torsional model for describing the physical dynamics. The acceleration data is tested by using the scheme of a back-to-back power circulation set-up, and the vibration properties are also studied.

A New Computational Procedure to Predict Transient Hydroplaning Performance of a Tire

2001 ◽  
Vol 29 (1) ◽  
pp. 2-22 ◽  
Author(s):  
T. Okano ◽  
M. Koishi
Keyword(s):  
Complex Geometry ◽  
Fluid Flows ◽  
Computational Procedure ◽  
Vehicle Body ◽  
Fluid Viscosity ◽  
Safe Driving ◽  
Transient Phenomena ◽  
Vehicle Velocity ◽  
Fixed Reference ◽  
Volume Method

Abstract “Hydroplaning characteristics” is one of the key functions for safe driving on wet roads. Since hydroplaning depends on vehicle velocity as well as the tire construction and tread pattern, a predictive simulation tool, which reflects all these effects, is required for effective and precise tire development. A numerical analysis procedure predicting the onset of hydroplaning of a tire, including the effect of vehicle velocity, is proposed in this paper. A commercial explicit-type FEM (finite element method)/FVM (finite volume method) package is used to solve the coupled problems of tire deformation and flow of the surrounding fluid. Tire deformations and fluid flows are solved, using FEM and FVM, respectively. To simulate transient phenomena effectively, vehicle-body-fixed reference-frame is used in the analysis. The proposed analysis can accommodate 1) complex geometry of the tread pattern and 2) rotational effect of tires, which are both important functions of hydroplaning simulation, and also 3) velocity dependency. In the present study, water is assumed to be compressible and also a laminar flow, indeed the fluid viscosity, is not included. To verify the effectiveness of the method, predicted hydroplaning velocities for four different simplified tread patterns are compared with experimental results measured at the proving ground. It is concluded that the proposed numerical method is effective for hydroplaning simulation. Numerical examples are also presented in which the present simulation methods are applied to newly developed prototype tires.

scholarly journals Modeling and Analysis on Teacher-Student Relationship

2019 ◽  
Vol 2019 ◽  
pp. 1-7
Author(s):  
Li Xu ◽  
Qi Yang
Keyword(s):  
Discrete Model ◽  
Equation Model ◽  
Reciprocal Relations ◽  
Modeling And Analysis ◽  
Teacher Student ◽  
Teacher Student Relationship ◽  
Sample Data ◽  
Teachers And Students ◽  
Student Relationship ◽  
The Relationship

Although the teacher-student relationship has been addressed in some studies, the cooperation or reciprocal relations between teachers and students have not been explored sufficiently. In this paper, a difference equation model is applied to express the relationship, stability analysis at the positive steady state of the discrete model is done to verify that the performance output is not empty, and hypothesis testing is conducted to show the validity of the model by means of sample data from a college. Then some reasonable suggestions are proposed to improve the performance output of teachers and students.

Simulation Optimization of Backrest Mechanism of Separable Bed Chair System

2021 ◽  
Vol 15 ◽  
pp. 1114-1123
Author(s):  
Meng Ning ◽  
Zhi Wu ◽  
Lianjie Chen ◽  
Fan Zhang ◽  
Huitao Chen
Keyword(s):  
Sudden Change ◽  
Optimal Solution ◽  
Simulation Software ◽  
Final Solution ◽  
Integration System ◽  
Modeling And Analysis ◽  
Movement Characteristics ◽  
Fixed Structure ◽  
The Relationship ◽  
Research And Design

Research and design an intelligent bed and chair integration system for assisting inconvenient mobility and aging population. The system consists of a removable detached wheelchair and a c-shaped bed with a fixed structure. The user can switch freely between the mobile wheelchair and the bed to meet the user's requirements of free movement and repositioning.Through the simulation software to analyze the movement characteristics of the bed backboard, the angle of the take-off and landing of the backboard and the sudden change of the take-off and abrupt angular velocity will cause the user to have dizziness and discomfort. In the case of determining the speed of the driving push rod, the relationship between mechanism parameters and installation parameters is the key to affect the lifting rate of the rear plate. Modeling and analysis of each mechanism is performed to determine the relationship between the mechanism parameters and the take-off and landing speed of the backplane. After optimizing the mechanism, the simulation is compared again to obtain the optimal solution. Finally, the optimal solution parameter is the final solution to improve the overall comfort of the nursing bed.

Footbridges as an important part of a system: the context as an experience

2021 ◽  
Author(s):  
Toon Maas ◽  
Mohamad Tuffaha ◽  
Laurent Ney
Keyword(s):  
Design Process ◽  
Degrees Of Freedom ◽  
The Other ◽  
Infrastructure Projects ◽  
Good Design ◽  
Cultural Processes ◽  
The Relationship

<p>“A bridge has to be designed”. Every bridge is the exploration of all degrees of a freedom of a project: the context, cultural processes, technology, engineering and industrial skills. A successful bridge aims to dialogue with these degrees of freedom to achieve a delicate equilibrium, one that invites the participation of its users and emotes new perceptions for its viewers. In short, a good design “makes the bridge talk.”</p><p>Too often, the bridge, as an object, is reduced to its functionality. Matters of perceptions and experiences of the users are often not considered in the design process; they are relegated to levels of chance or treated as simple decorative matter. The longevity of infrastructure projects, in general, and bridges, in particular, highlights the deficiencies of such an approach. The framework to design bridges must include historical, cultural, and experiential dimensions. Technology and engineering are of paramount importance but cannot be considered as “an end in themselves but a means to an end”. This paper proposes to discuss three projects by Ney &amp; Partners that illustrate such a comprehensive exploration approach to footbridge design: the Poissy and Albi crossings and the Tintagel footbridge.</p><p>The footbridges of Poissy and Albi dialogue most clearly with their historical contexts, reconfiguring the relationship between old and new in the materiality and typology use. In Tintagel, legend replaces history. Becoming a metaphor for the void it crosses, the Tintagel footbridge illustrates the delicate dialogue of technology and engineering on one side and imagination and experience on the other.</p>

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