scholarly journals Characterization and Modelling of Various Sized Mountain Bike Tires and the Effects of Tire Tread Knobs and Inflation Pressure

2020 ◽  
Vol 10 (9) ◽  
pp. 3156 ◽  
Author(s):  
Andrew Dressel ◽  
James Sadauckas
Keyword(s):  
Simple Model ◽  
Lateral Stiffness ◽  
Tire Model ◽  
Laboratory Measurements ◽  
Inflation Pressure ◽  
Mountain Bike ◽  
Basic Model ◽  
Radial Stiffness ◽  
In Series ◽  
Distinguishing Features

Mountain bikes continue to be the largest segment of U.S. bicycle sales, totaling some USD 577.5 million in 2017 alone. One of the distinguishing features of the mountain bike is relatively wide tires with thick, knobby treads. Although some work has been done on characterizing street and commuter bicycle tires, little or no data have been published on off-road bicycle tires. This work presents laboratory measurements of inflated tire profiles, tire contact patch footprints, and force and moment data, as well as static lateral and radial stiffness for various modern mountain bike tire sizes including plus size and fat bike tires. Pacejka’s Motorcycle Magic Formula tire model was applied and used to compare results. A basic model of tire lateral stiffness incorporating individual tread knobs as springs in parallel with the overall tread and the inflated carcass as springs in series was derived. Finally, the influence of inflation pressure was also examined. Results demonstrated appreciable differences in tire performance between 29 × 2.3”, 27.5 × 2.8”, 29 × 3”, and 26 × 4” knobby tires. The proposed simple model to combine tread knob and carcass stiffness offered a good approximation, whereas inflation pressure had a strong effect on mountain bike tire behavior.

Testing of modified primary stiffness for heavy-haul locomotives operating on sharper-radius curves

2019 ◽  
Vol 233 (3) ◽  
pp. 531-548
Author(s):  
Pengfei Liu ◽  
Kai Wei ◽  
Kaiyun Wang ◽  
Quanbao Feng
Keyword(s):  
Load Transfer ◽  
Ride Comfort ◽  
Lateral Force ◽  
Mean Value ◽  
Lateral Stiffness ◽  
Coupled Vibration ◽  
Radial Stiffness ◽  
Longitudinal Stiffness ◽  
Negotiation Performance ◽  
Heavy Haul

For the typical wheelset drive subsystem with axle-suspended motor, the coupled vibration differential equations of wheelset and axle hung motor are derived. The mechanical model of traction rod is established. The subsystems are integrated into a whole locomotive-track coupled dynamic model which is verified from the aspects of load transfer and curving negotiation performance. To reduce the wheel–rail dynamic interaction of six-axle heavy-haul locomotive passing through curves in old existing lines, the parametric optimization flow of primary rubber joint is presented. The stiffness of 12 new rubber joints equipped in drawbars is tested and the stiffness dispersions are investigated. The research results show that, for a single rubber joint, the maximum and minimum values of radial stiffness can, respectively, increase and reduce by 16.2% and 33% with respect to the test mean value. For the assembled axle-box with upper and lower drawbars, the test longitudinal and lateral stiffness increase by 18% and 46%, respectively, relative to the designed values. A distinct dispersion phenomenon in the stiffness distributions of rubber samples is found. By combining with the numerical simulation results, the primary longitudinal stiffness is optimized from 199 MN/m to 52 MN/m, as the lateral stiffness changes from 6.89 MN/m to 2.6 MN/m. The final running test indicates that the optimized parameters can reduce the wheel–rail lateral force by 12% in the 300 m radius curve. The ride comfort could still keep in the same level, and the running stability has not been deteriorated.

scholarly journals On the total loss probability of service stages in series

1990 ◽  
Vol 22 (1) ◽  
pp. 260-262
Author(s):  
P.-J. Courtois
Keyword(s):  
Simple Model ◽  
Loss Rate ◽  
Loss Probability ◽  
Total Loss ◽  
Finite Queues ◽  
In Series

The problem addressed here is related to the minimization of the total loss probability in series of finite queues at which customers are rejected if the waiting capacity is exceeded. More precisely, one is concerned with the question of determining whether or not there may exist conditions under which an increase of the loss rate at one queue, e.g. at the most upstream one, could result in a decrease of the total loss rate throughout the whole network. The answer obtained in the context of a simple model is negative.

Cord Force Measurements in Radial Tires

1972 ◽  
Vol 94 (2) ◽  
pp. 678-682 ◽  
Author(s):  
J. D. Walter
Keyword(s):  
Strain Gage ◽  
Simple Formula ◽  
Rubber Matrix ◽  
Force Measurements ◽  
Inflation Pressure ◽  
Force Transducers ◽  
In Series ◽  
Straight Ahead ◽  
Automobile Tires

Miniature force transducers in the form of strain gage instrumented tension links are used to measure the loads developed in the rayon cords in both the stabilizer and body plies of automobile tires of radial construction. These transducers are placed in series with the cord and are embedded in the rubber matrix of the tire during building. Cord forces are obtained at various wheel loads and inflation pressures for straight ahead rolling and cornering of the tires in operation. It is shown that a relatively simple formula can be used to theoretically predict the cord tension developed in the sidewall region due to inflation pressure.

Efficient Pricing in Data Transmission Networks: The Argentine experience

First Monday ◽  
1997 ◽  
Author(s):  
Mauricio Drelichman
Keyword(s):  
Simple Model ◽  
Data Transmission ◽  
Descriptive Analysis ◽  
Internet Access ◽  
End User ◽  
Transmission Networks ◽  
Fourth Section ◽  
The Third ◽  
Basic Model ◽  
Linear Demand

This paper develops a model to reflect the Argentine market for end-user Internet access and draws conclusions on certain aspects of economic efficiency. After the Introduction, the second section, entitled A Simple Model, provides a descriptive analysis of the market and its related industry, deriving a stylized technology and setting up a basic model. The third part of the paper, An Application to the Argentine Market, applies the model to Argentina, while the fourth section, Lessons from a Linear Demand Case, examines the results of the model under certain conditions. The model and the linear demand case are fully developed in the Appendix.

Tire Longitudinal Mechanics Properties under Various Braking Conditions

2014 ◽  
Vol 654 ◽  
pp. 82-86
Author(s):  
Hai Dong Wu ◽  
Kong Hui Guo
Keyword(s):  
Dynamic Properties ◽  
Tire Model ◽  
In Series ◽  
Mass Spring

A dynamical tire model under uneven road is reviewed and the model is adapted to carry out simulation of various braking conditions. The damped characters of the tire at low rotated speed are improved through the study on the system of mass-spring-damper in series. A simple and effective brake model is designed and several extreme braking conditions are simulated. The results of simulation show obvious dynamic properties of the tire at various braking excitation.

scholarly journals Femtoscopic and Nonfemtoscopic Two-Particle Correlations inA+Aandp+pCollisions at RHIC and LHC Energies

2013 ◽  
Vol 2013 ◽  
pp. 1-23 ◽  
Author(s):  
Yu. M. Sinyukov ◽  
S. V. Akkelin ◽  
Iu. A. Karpenko ◽  
V. M. Shapoval
Keyword(s):  
Correlation Function ◽  
Simple Model ◽  
Proton Proton ◽  
Proton Collisions ◽  
Basic Model ◽  
Kaon Interferometry ◽  
Bose Einstein ◽  
Proton Proton Collisions ◽  
Theoretical Results ◽  
Einstein Correlation

The theoretical review of the last femtoscopy results for the systems created in ultrarelativisticA+A,p+p, andp+Pbcollisions is presented. The basic model, allowing to describe the interferometry data at SPS, RHIC, and LHC, is the hydrokinetic model. The model allows one to avoid the principal problem of the particlization of the medium at nonspace-like sites of transition hypersurfaces and switch to hadronic cascade at a space-like hypersurface with nonequilibrated particle input. The results for pion and kaon interferometry scales inPb+PbandAu+Aucollisions at LHC and RHIC are presented for different centralities. The new theoretical results as for the femtoscopy of small sources with sizes of 1-2 fm or less are discussed. The uncertainty principle destroys the standard approach of completely chaotic sources: the emitters in such sources cannot radiate independently and incoherently. As a result, the observed femtoscopy scales are reduced, and the Bose-Einstein correlation function is suppressed. The results are applied for the femtoscopy analysis ofp+pcollisions ats=7 TeV LHC energy andp+Pbones ats=5.02 TeV. The behavior of the corresponding interferometry volumes on multiplicity is compared with what is happening for centralA+Acollisions. In addition the nonfemtoscopic two-pion correlations in proton-proton collisions at the LHC energies are considered, and a simple model that takes into account correlations induced by the conservation laws and minijets is analyzed.

Experimental Testing and Analysis of Inerter Devices

2008 ◽  
Vol 131 (1) ◽  
Author(s):  
Christos Papageorgiou ◽  
Neil E. Houghton ◽  
Malcolm C. Smith
Keyword(s):  
Closed Loop ◽  
Experimental Testing ◽  
Hydraulic Damper ◽  
Basic Model ◽  
Wide Range ◽  
In Series ◽  
Mechanical Element ◽  
Mechanical Devices ◽  
The Ideal ◽  
Loop Stability

This paper presents a first in-depth experimental study of mechanical devices that are designed to approximate the dynamics of the ideal inerter, which is a two-terminal mechanical element analogous to the ungrounded capacitor. The focus of the paper is experimental testing and identification of stand-alone inerter devices as well as the study of practical issues involved in their feedback control using standard hydraulic damper test rigs. Two contrasting inerter embodiments are studied, one in which a flywheel is driven by a rack-and-pinion mechanism and the other employing a ballscrew. Due to the fact that the ideal inerter is a dynamic element whose admittance function is 90 deg out of phase with that of the ideal damper, particular attention is needed to ensure closed-loop stability in testing using standard hydraulic damper test rigs. As expected, instability is observed in default configurations, and it is seen to manifest itself in a nonlinear manner with backlash playing a significant role. By using a basic model of the hydraulic rig and a model of an ideal inerter with backlash, the nature of the instability is reproduced and explained in a qualitative way. To achieve closed-loop stability without the need to redesign the controller as a function of the load, a methodology is proposed involving the design of a mechanical buffer network to be connected in series with the inerter device. It is demonstrated that this approach removes the instability problem for a wide range of inertance loads. Finally, the dynamic characteristics of the inerter devices are identified. It is verified experimentally that the admittance of the devices approaches the ideal inerter admittance over a useful frequency range and that friction in the devices is a major source of deviation from the ideal inerter behavior.

scholarly journals A Simple Model of Interbank Trading with Tiered Remuneration

2020 ◽  
Vol 8 (1) ◽  
pp. 74
Author(s):  
Toshifumi Nakamura
Keyword(s):  
Simple Model ◽  
Interest Rates ◽  
European Central Bank ◽  
Interbank Market ◽  
Interest Rate Policy ◽  
European Central ◽  
Basic Model ◽  
National Bank ◽  
Rate Policy ◽  
Negative Interest Rate Policy

A negative interest rate policy is often accompanied by tiered remuneration, which allows exemption from negative rates. This study proposes a basic model of interest rates in an interbank market with a tiering system. The results largely mirror actual market developments in late 2019, when the European Central Bank introduced the tiering system and the Switzerland National Bank modified it.

Load, Speed and Inflation Pressure Effects on Rolling Loss Distribution in Automobile Tires

1988 ◽  
Vol 16 (2) ◽  
pp. 78-95 ◽  
Author(s):  
J. D. Clark ◽  
D. J. Schuring
Keyword(s):  
Thermal Model ◽  
Thermal Modeling ◽  
Infrared Camera ◽  
Pressure Effects ◽  
Direct Result ◽  
Laboratory Measurements ◽  
Inflation Pressure ◽  
Camera System ◽  
Temperature Distributions ◽  
Modeling Techniques

Abstract The effect of tire load, speed, and cold inflation pressure on the rolling loss contribution of any tire region is determined by numerical calculations involving both laboratory measurements and thermal modeling techniques. Laboratory measurements include tire surface temperature distributions obtained from an infrared camera system; thermal modeling is based on finite-difference procedures. Results are presented in two formats: (1) plots of rolling loss distributions from bead to bead and (2) contributions of tread, shoulder, sidewall, and bead regions. The first format is a direct result of the thermal model; the second is derived from multiple-regression operations. Both formats are given as functions of load, cold inflation pressure, and speed. Beahvior in the tread region is shown to be unique.

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