scholarly journals Self-Excited Lateral Vibrations of Rolling Tires

2015 ◽  
Author(s):  
Dénes Takács ◽  
Gábor Stépan
Keyword(s):  
Numerical Simulations ◽  
Mechanical Model ◽  
Critical Parameter ◽  
Lateral Deformation ◽  
Contact Patch ◽  
Lateral Vibrations ◽  
Low Degree ◽  
Minimum Number ◽  
Lateral Mode ◽  
Parameter Ranges

In this study, a low degree-of-freedom mechanical model of a rolling tire is constructed, in which the lateral deformation of the contact patch and tire carcass is considered. The so-called delayed contact patch model is implemented and combined with a simple tire carcass model. The interaction between the contact patch and the carcass together with the lateral mode of the attached suspension system is modeled by means of minimum number of relevant parameters in a simplified way in order to construct analytical results. Critical parameter ranges of self-excited vibrations are determined against the longitudinal speed of the tire. The intricate shapes of the corresponding tire deformations are presented by means of numerical simulations.

scholarly journals Pinning synchronization of the drive and response dynamical networks with lag

2014 ◽  
Vol 24 (3) ◽  
pp. 257-270 ◽  
Author(s):  
Bohui Wen ◽  
Mo Zhao ◽  
Fanyu Meng
Keyword(s):  
Numerical Simulations ◽  
Lyapunov Stability ◽  
Stability Theory ◽  
Lyapunov Stability Theory ◽  
Schur Complement ◽  
Pinning Control ◽  
Lag Synchronization ◽  
Dynamical Networks ◽  
General Complex ◽  
Minimum Number

Abstract This paper investigates the pinning synchronization of two general complex dynamical networks with lag. The coupling configuration matrices in the two networks are not need to be symmetric or irreducible. Several convenient and useful criteria for lag synchronization are obtained based on the lemma of Schur complement and the Lyapunov stability theory. Especially, the minimum number of controllers in pinning control can be easily obtained. At last, numerical simulations are provided to verify the effectiveness of the criteria

Calculation of the Periodic Solution in Nakamura’s Model

2012 ◽  
Vol 256-259 ◽  
pp. 1648-1651
Author(s):  
Bin Zhen ◽  
Zhang Jun Liu
Keyword(s):  
Periodic Solution ◽  
Hopf Bifurcation ◽  
Numerical Simulations ◽  
Bifurcation Analysis ◽  
Energy Method ◽  
Analytic Solution ◽  
Measure Data ◽  
Lateral Vibration ◽  
Lateral Vibrations

Nakamura’s model is one of the most practical models describing the lateral vibrations of footbridges induced by pedestrians. This paper presents a calculation of the periodic solution in Nakamura’s model. After a Hopf bifurcation analysis of Nakamura’s model, the amplitude of the lateral vibration is computed by using the energy method. The correctness and accuracy of the calculation is demonstrated by numerical simulations. Then, how the factors and variables in Nakamura’s model effect the amplitude is investigated based on the analytic solution. Our analysis results may be used to explain why the most of the predict results of Nakamura’s model are larger than the measure data.

scholarly journals Investigation of the components of the cornering resistance of a tracked vehicle on a solid support base

2021 ◽  
Vol 1 (2) ◽  
pp. 51-62
Author(s):  
B.V. Padalkin ◽  
Keyword(s):  
Mathematical Model ◽  
Reaction Force ◽  
Vertical Axis ◽  
Support Surface ◽  
Tracked Vehicle ◽  
Tracked Vehicles ◽  
Contact Patch ◽  
Minimum Number ◽  
The Moment ◽  
Propulsion Unit

The purpose of the study is to increase the completeness and reliability of approaches to deter-mining the components of the cornering resistance a tracked vehicle, as well as to create a method for their assessment, which will be suitable for practical calculations. The article analyzes two components of the moment of cornering resistance of the tracked vehi-cle, which can be distinguished if we consider the interaction of the caterpillar with the support base through separate contact spots (active sections of the tracks located under the road wheels). The first component arises from the linear movement of the active sections of the tracks. The second is caused by the rotational movement of the contact patch about the vertical axis. The paper presents a mathematical model of the interaction of the propeller and a dense support base, which makes it possible to study the dependence of the components of the moment of corner-ing resistance on the geometric parameters of the undercarriage of a tracked vehicle. The horizontal reaction force in this case is presented as a function of the slip coefficient. The possibility of realiz-ing various adhesion qualities of the propulsion unit in the longitudinal and transverse directions of sliding is provided. The model assumes a preliminary division of the contact patch into a finite number of elementary areas. Since the number of elementary sites affects the result, the article con-ducted a study to determine the minimum number of sites to ensure acceptable accuracy. An analysis of the expressions available in the literature was carried out to determine the speci-fied component of the cornering resistance. The new empirical relationships that better agree with the mathematical model were proposed. The study of several existing tracked vehicles, differing in the mass and size of the track support surface, made it possible to conclude that it is advisable to take into account the moment of cornering resistance of the contact patch for various types of tracked vehicles.

scholarly journals Biogeochemical impacts of flooding discharge with high suspended sediment on coastal seas: a modeling study for a microtidal open bay

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yasuhiro Hoshiba ◽  
Hiroyasu Hasumi ◽  
Sachihiko Itoh ◽  
Yoshimasa Matsumura ◽  
Satoshi Nakada
Keyword(s):  
Numerical Simulations ◽  
Suspended Sediment ◽  
Nutrient Content ◽  
Sea Surface ◽  
Surface Salinity ◽  
Reference Case ◽  
Riverine Water ◽  
Flooding Event ◽  
Parameter Ranges ◽  
Flooding Events

AbstractFreshwater, suspended sediment matter (SSM), and nutrients discharged from rivers into the ocean have large impacts on biological production. In particular, during floods, coastal areas are greatly stirred up and large amounts of nutrients are supplied to the sea surface. We investigate the biogeochemical impact of flooding river discharges containing a large amount of SSM by conducting numerical simulations for a specific flooding event of the Yura River, Japan. Parameters are varied over wide ranges of SSM properties and nutrient content in riverine water. Two qualitatively different regimes of the riverine plume, hypopycnal and hyperpycnal, appear within realistic parameter ranges. Compared with the reference case without SSM, the surface salinity (nutrients) within the riverine plume becomes lower (higher) in hypopycnal cases and higher (lower) in hyperpycnal cases within a few days after the flooding discharge. These results suggest the necessity of properly taking into account the effect of SSM in assessing the influence of high river discharges on coastal biogeochemistry. It is the case not only for the specific river and event we are dealing with but also for other flooding events and other rivers and connecting coastal seas.

Chaos in Robert Hooke's inverted cone

2007 ◽  
Vol 463 (2081) ◽  
pp. 1259-1269 ◽  
Author(s):  
Médéric Argentina ◽  
Pierre Coullet ◽  
Jean-Marc Gilli ◽  
Marc Monticelli ◽  
Germain Rousseaux
Keyword(s):  
Dynamical Systems ◽  
Numerical Simulations ◽  
Gravity Field ◽  
Chaos Theory ◽  
Mechanical Model ◽  
Period Doubling ◽  
The Sun ◽  
Chaotic Motions ◽  
Robert Hooke ◽  
Classical Experiment

Robert Hooke is perhaps one of the first scientists to have met chaotic motions. Indeed, to invert a cone and let a ball move in it was a mechanical model used by him to mimic the motion of a planet around a centre of force like the Sun. However, as the cone is inclined with respect to the gravity field, the perfect rosace followed by the particle becomes chaotic meanderings. We revisit this classical experiment designed by Hooke with the modern tools of dynamical systems and chaos theory. By a combination of both numerical simulations and experiments, we prove that the scenario of transition to the chaotic behaviour is through a period-doubling instability.

scholarly journals Influence of the Longitudinal and Lateral Suspension Damping on the Vibration Behaviour in the Railway Vehicles

2015 ◽  
Vol 62 (1) ◽  
pp. 115-140 ◽  
Author(s):  
Mădălina Dumitriu
Keyword(s):  
Numerical Simulations ◽  
Linear Model ◽  
Critical Velocity ◽  
Dynamic Behaviour ◽  
Response Frequency ◽  
Railway Vehicles ◽  
Basic Properties ◽  
Lateral Vibrations ◽  
Random Behaviour ◽  
Frequency Functions

Abstract The paper focuses on the influence of the longitudinal and lateral suspension damping in correlation with the velocity upon the vibration behaviour of the railway vehicles while moving on a tangent track. The numerical simulations are developed based on a linear model of a 17-degree of freedom vehicle that allows the evaluation of the dynamic behaviour of the vehicle in a sub-critical velocity. Based on the response frequency functions of the vehicle in a harmonic and in a random behaviour, a series of basic properties of the stable behaviour of the forced lateral vibrations has been made evident, as well as the opportunities to lower the level of the carbody vibrations by changing the suspension damping.

scholarly journals Oscillations Control of Rocking-Block-Type Buildings by the Addition of a Tuned Pendulum

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Luca Collini ◽  
Rinaldo Garziera ◽  
Kseniia Riabova ◽  
Mariya Munitsyna ◽  
Alessandro Tasora
Keyword(s):  
Numerical Simulations ◽  
Approximation Method ◽  
Dry Friction ◽  
Mechanical Model ◽  
Horizontal Plane ◽  
Galerkin Approximation ◽  
Block Type ◽  
Theoretical Part ◽  
Lagrange Formulation ◽  
Rocking Block

This study deals with the dynamical evolutions exhibited by a simple mechanical model of building, comprising a parallelepiped standing on a horizontal plane. The main goal is the introduction of a pendulum in order to reduce oscillations. The theoretical part of the work consists of a Lagrange formulation and Galerkin approximation method, and dry friction has also been considered. From the analytical/numerical simulations, we derive some important conclusions, providing us with the tools suitable for the design of absorbers in practical cases.

scholarly journals MULTI-FIELD STABILIZED FINITE ELEMENT APPROXIMATIONS FOR OLDROYD-B FLUID FLOWS

2013 ◽  
Vol 12 (1) ◽  
pp. 61
Author(s):  
D. D. Dos Santos ◽  
S. Frey ◽  
M. F. Naccache ◽  
P. R. de Souza Mendes
Keyword(s):  
Finite Element ◽  
Numerical Simulations ◽  
Mechanical Model ◽  
Stokes Problem ◽  
Fluid Flows ◽  
Momentum Balance ◽  
Balance Equations ◽  
Stabilized Finite Element ◽  
Finite Element Approximations ◽  
Extra Stress

This work concerns with numerical simulations of creeping and inertial flows of viscoelastic fluids. The mechanical model consists of mass and momentum balance equations, coupled with the Oldroyd-B fluid. The model is approximated by a multi-field Galerkin least-squares (GLS) methodology in terms of extra-stress, velocity and pressure. The GLS method, introduced by Hughes et al. (1986) in the context of the Stokes problem for Newtonian fluidflows, allows the use of combinations of equal-order finite element interpolations and remains stable even for elastic- and inertiadominated fluid flows. Some steady simulations of Oldroyd-B fluids, flowing over a slot, are herein carried out. The influence of inertia and fluid viscoelasticity is taken into account ranging the Reynolds and Weissenberg numbers for relevant values of this flow. The results are in accordance to the viscoelastic literature and reassure the fine stability features of the GLS formulation.

Distribution of Longitudinal Forces in the Body of Passenger Trains

2015 ◽  
Vol 809-810 ◽  
pp. 1175-1180 ◽  
Author(s):  
Camil Ion Crăciun ◽  
Mădălina Dumitriu
Keyword(s):  
Numerical Simulations ◽  
Mechanical Model ◽  
Rigid Bodies ◽  
The Body ◽  
Nonlinear Characteristic ◽  
Braking System ◽  
Longitudinal Dynamic ◽  
Dynamic Forces ◽  
Passenger Trains ◽  
Over Time

The distribution and the size of longitudinal dynamic forces that develop in the train body found in braking system are influenced by the length of the train. To determine these forces, it is used a mechanical model consisting of rigid bodies, representing the train vehicles, connected by elastic and damping elements with the nonlinear characteristic that shapes the buffer and draw-gear. The results based on numerical simulations highlight the emergence of dynamic longitudinal forces during braking, their evolution over time and the distribution of maximum compression and stretching forces that develop in buffer and draw-gear devices, for different lengths of the passenger train.

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