scholarly journals Influence of Road Camber on Motorcycle Stability

2008 ◽  
Vol 75 (6) ◽  
Author(s):  
Simos Evangelou ◽  
David J. N. Limebeer ◽  
Maria Tomas Rodriguez
Keyword(s):  
High Speed ◽  
Road Vehicles ◽  
Adaptive Controllers ◽  
The Road ◽  
Tire Force ◽  
Wheeled Vehicle ◽  
Road Surfaces ◽  
The Stability ◽  
Induced Changes ◽  
Local Road

This paper studies the influence of road camber on the stability of single-track road vehicles. Road camber changes the magnitude and direction of the tire force and moment vectors relative to the wheels, as well as the combined-force limit one might obtain from the road tires. Camber-induced changes in the tire force and moment systems have knock-on consequences for the vehicle’s stability. The study makes use of computer simulations that exploit a high-fidelity motorcycle model whose parameter set is based on a Suzuki GSX-R1000 sports machine. In order to study camber-induced stability trends for a range of machine speeds and roll angles, we study the machine dynamics as the vehicle travels over the surface of a right circular cone. Conical road surfaces allow the machine to operate at a constant steady-state speed, a constant roll angle, and a constant road camber angle. The local road-tire contact behavior is analyzed by approximating the cone surface by moving tangent planes located under the road wheels. There is novelty in the way in which adaptive controllers are used to center the vehicle’s trajectory on a cone, which has its apex at the origin of the inertial reference frame. The results show that at low speed both the weave- and wobble-mode stabilities are at a maximum when the machine is perpendicular to the road surface. This trend is reversed at high speed, since the weave- and wobble-mode dampings are minimized by running conditions in which the wheels are orthogonal to the road. As a result, positive camber, which is often introduced by road builders to aid drainage and enhance the friction limit of four-wheeled vehicle tires, might be detrimental to the stability of two-wheeled machines.

Uncertainty in the standardized method "Characterization of the acoustic properties of road surfaces" by CEN TC227 WG5

2021 ◽  
Vol 263 (6) ◽  
pp. 314-322
Author(s):  
Gijsjan van Blokland ◽  
Luc Goubert
Keyword(s):  
Calculation Model ◽  
Acoustic Properties ◽  
Noise Emission ◽  
Road Vehicles ◽  
The Road ◽  
Road Pavement ◽  
Road Surfaces ◽  
Standardized Method ◽  
Limited Accuracy

TC227 of CEN has developed a method to determine the effect of the road pavement on the sound emission of road vehicles. The proposed methods can be applied to define the acoustic label value of a generic or proprietary pavement type, to check compliance of a pavement with the specifications for that pavement type and to monitor the development of the acoustic properties over the lifetime of the product. With the procedure one can additionally derive the coefficients for the pavement correc tion in the noise emission formulae for road vehicles in the CNOSSOS-EU calculation model. The application of the method exhibits a limited accuracy. The paper investigates the sources of uncertainty of the standardized method and combine the contributions into a single overall uncertainty according to the procedures laid down in Guide 98-3 of ISO. The uncertainty is determined for each of the listed application areas. From the uncertainty analysis the major contributions are identified. Improvement of the method shall focus on only these contributions.

scholarly journals RELIABILITY CRITERION AND A MODEL FOR DETERMINING THE OPTIMAL SPEED OF MOVEMENT ON AUTOMOBILE ROADS IN WINTER SLIDING CONDITIONS

2020 ◽  
Vol 6 (444) ◽  
pp. 119-125
Author(s):  
D. E. Yessentay ◽  
◽  
A. K. Kiyalbaev ◽  
S. N. Kiyalbay ◽  
N. V. Borisуuk ◽  
...  
Keyword(s):  
Traffic Accidents ◽  
Road Traffic ◽  
Rolling Resistance ◽  
Main Criterion ◽  
The Road ◽  
Optimal Speed ◽  
Road Surfaces ◽  
Braking Distance ◽  
Effective Decision ◽  
The Stability

The article presents a model for establishing the optimal speed of movement on highways, taking into account the determination of the braking distance in winter slippery conditions. According to the research results, it was established that the main criterion for the formation of road accidents on highways in winter slippery conditions is the drivers' underestimation of the adhesion qualities of road surfaces. The main criterion of the model under consideration is the interaction of the car wheel (braking distance) with the road (adhesion coefficient) and is a complex that characterizes the stability of the car rolling over on slippery surfaces and the driver's actions in making an effective decision and the duration of the reaction time. In the proposed mathematical model, the accident rate on a slippery road is estimated by the coefficient of adhesion of icy road surfaces, the value of the load or the average wheel pressure. Also, the frequency of load application, the amount of deflection of the coating (at an air temperature above +20 ° C), rolling resistance, the coefficient of adhesion of the car wheel to the coating. One of the main characteristics of the model is a subsystem - the average pressure p = Q / S (S is the area of the imprint of the wheel, cm²), etc. Thus, in the process of analyzing the results of the causes of road traffic accidents, the factors of the driver's reliability and the decisions made will be taken into account, which depend on the speed of vehicles in any condition of the road surface.

Theoretical Road Damage Due to Dynamic Tyre Forces of Heavy Vehicles Part 1: Dynamic Analysis of Vehicles and Road Surfaces

1988 ◽  
Vol 202 (2) ◽  
pp. 103-108 ◽  
Author(s):  
D Cebon
Keyword(s):  
Dynamic Response ◽  
Dynamic Analysis ◽  
Full Scale ◽  
Heavy Vehicles ◽  
Road Vehicles ◽  
Vehicle Simulation ◽  
The Road ◽  
Road Surfaces ◽  
Full Scale Tests

Theory is presented for simulating the dynamic wheel forces generated by heavy road vehicles and the resulting dynamic response of road surfaces to these loads. Sample calculations are provided and the vehicle simulation is validated with data from full-scale tests. The methods are used in the accompanying paper to simulate the road damage done by a tandem-axle vehicle.

scholarly journals Assessment of Passenger’s Ride Comfort of a Tricycle

2018 ◽  
Vol 9 (2) ◽  
pp. 10-17 ◽  
Author(s):  
Ján Dižo ◽  
Miroslav Blatnický ◽  
Rafał Melnik
Keyword(s):  
Surface Quality ◽  
Software Package ◽  
Ride Comfort ◽  
Vehicle Model ◽  
Road Vehicles ◽  
The Road ◽  
Multibody Model ◽  
Wheeled Vehicle ◽  
Dynamic Analyses ◽  
On The Road

Abstract Passenger ride comfort of road vehicles is one of the most important performances of vehicle. The research of automotive passenger ride comfort is getting more and more important. In this contribution, the multibody model of a three-wheeled vehicle and analyses of passenger ride comfort is presented. The vehicle model and dynamic analyses were performed using the Simpack software package. The dynamic analyses of the vehicle driving were carried out on the road model with different surface quality. Analyses were focused on assessment of the passenger ride comfort on a driver seat.

Optimizing Dynamic Performance of High-Speed Road Vehicles Using Aerodynamic Aids

2016 ◽  
Author(s):  
Tushita Sikder ◽  
Saurabh Kapoor ◽  
Yuping He
Keyword(s):  
High Speed ◽  
Dynamic Performance ◽  
Lateral Stability ◽  
Road Vehicles ◽  
Ansys Fluent ◽  
The Road ◽  
High Speeds ◽  
Air Stream ◽  
High Dependency ◽  
Drag And Lift

This paper focuses on the effects of aerodynamic aids on the lateral and longitudinal dynamics of high-speed road vehicles. Aerodynamic aids, such as spoilers, can reduce drag to improve vehicle’s fuel economy and acceleration performance. On the other hand, aerodynamic aids can be utilized to enhance the lateral stability of the vehicle at high speeds by generating downforce or negative lift. However, the co-existence of drag and lift creates a paradox, that is, the downforce generated to improve car’s high-speed stability acts as a parasitic force on the car-body and slows down the vehicle forward speed. This paper will illustrate the juxtaposed effects of the aerodynamic forces on the lateral stability of the vehicle. Airfoils in the role of external aerodynamic aids will be examined based on their shapes, geometrical configurations, and at varying relative positions using the CFD technique. Moreover, the effects of attack angles, change in Reynold’s numbers (air stream velocities), and varying ground clearance on the lateral dynamics of the vehicle will be analyzed using numerical simulations with ANSYS FLUENT software package. The results and reliability of CFD simulations has a high dependency on the size of the grid, thus the aim of this paper will be to ensure that the results are independent of the grid size. Selection of the optimum design will be based on performance parameters like drag and lift coefficients. The challenge posed here is to ensure the lateral stability of the vehicle while achieving high average speed. Therefore, the main goal of the study is to enhance handling capabilities of the road vehicles at high speeds while minimizing the drag.

A Statistical Study of Process Variables to Optimize a High Speed Curtain Coater: Part I

TAPPI Journal ◽  
2009 ◽  
Vol 8 (1) ◽  
pp. 20-26 ◽  
Author(s):  
PEEYUSH TRIPATHI ◽  
MARGARET JOYCE ◽  
PAUL D. FLEMING ◽  
MASAHIRO SUGIHARA
Keyword(s):  
Boundary Layer ◽  
Experimental Design ◽  
High Speed ◽  
Statistical Study ◽  
Process Variables ◽  
High Speeds ◽  
The Stability ◽  
Air Removal ◽  
Removal System

Using an experimental design approach, researchers altered process parameters and material prop-erties to stabilize the curtain of a pilot curtain coater at high speeds. Part I of this paper identifies the four significant variables that influence curtain stability. The boundary layer air removal system was critical to the stability of the curtain and base sheet roughness was found to be very important. A shear thinning coating rheology and higher curtain heights improved the curtain stability at high speeds. The sizing of the base sheet affected coverage and cur-tain stability because of its effect on base sheet wettability. The role of surfactant was inconclusive. Part II of this paper will report on further optimization of curtain stability with these four variables using a D-optimal partial-facto-rial design.

Tire-Road Interactions — Harmony or Conflict?

1989 ◽  
Vol 17 (1) ◽  
pp. 66-84
Author(s):  
A. R. Williams
Keyword(s):  
Rolling Resistance ◽  
Major Effect ◽  
Road Surface ◽  
Interactive Effects ◽  
Central Theme ◽  
Water Drainage ◽  
The Road ◽  
Truck Tires ◽  
Road Surfaces ◽  
Tire Wear

Abstract This is a summary of work by the author and his colleagues, as well as by others reported in the literature, that demonstrate a need for considering a vehicle, its tires, and the road surface as a system. The central theme is interaction at the footprint, especially that of truck tires. Individual and interactive effects of road and tires are considered under the major topics of road aggregate (macroscopic and microscopic properties), development of a novel road surface, safety, noise, rolling resistance, riding comfort, water drainage by both road and tire, development of tire tread compounds and a proving ground, and influence of tire wear on wet traction. A general conclusion is that road surfaces have both the major effect and the greater potential for improvement.

LANDSLIDE RISK MANAGEMENT IN THE COASTAL ZONE OF THE KUIBYSHEV RESERVOIR DUE THE DESIGN OF HIGH-SPEED LINE "MOSCOW-KAZAN"

2017 ◽  
Author(s):  
Nikolai Petrov ◽  
Nikolai Petrov ◽  
Inna Nikonorova ◽  
Inna Nikonorova ◽  
Vladimir Mashin ◽  
...  
Keyword(s):  
High Speed ◽  
Computational Models ◽  
Stable State ◽  
Landslide Risk ◽  
Kuibyshev Reservoir ◽  
Stepped Surface ◽  
The Stability ◽  
Landslide Slope ◽  
The Village

High-speed railway "Moscow-Kazan" by the draft crosses the Volga (Kuibyshev reservoir) in Chuvashia region 500 m below the village of New Kushnikovo. The crossing plot is a right-bank landslide slope with a stepped surface. Its height is 80 m; the slope steepness -15-16o. The authors should assess the risk of landslides and recommend anti-landslide measures to ensure the safety of the future bridge. For this landslide factors have been analyzed, slope stability assessment has been performed and recommendations have been suggested. The role of the following factors have been analyzed: 1) hydrologic - erosion and abrasion reservoir and runoff role; 2) lithologyc (the presence of Urzhum and Northern Dvina horizons of plastically deformable rocks, displacement areas); 3) hydrogeological (the role of perched, ground and interstratal water); 4) geomorphological (presence of the elemental composition of sliding systems and their structure in the relief); 5) exogeodynamic (cycles and stages of landslide systems development, mechanisms and relationship between landslide tiers of different generations and blocks contained in tiers). As a result 6-7 computational models at each of the three engineering-geological sections were made. The stability was evaluated by the method “of the leaning slope”. It is proved that the slope is in a very stable state and requires the following measures: 1) unloading (truncation) of active heads blocks of landslide tiers) and the edge of the plateau, 2) regulation of the surface and groundwater flow, 3) concrete dam, if necessary.

Dynamic Performance of High-Speed Electric Multiple Unit within Multi-Body System Simulation

2019 ◽  
Vol 12 (4) ◽  
pp. 339-349
Author(s):  
Junguo Wang ◽  
Daoping Gong ◽  
Rui Sun ◽  
Yongxiang Zhao
Keyword(s):  
High Speed ◽  
Rapid Development ◽  
Dynamic Performance ◽  
Body System ◽  
High Speed Railway ◽  
Evaluation Indexes ◽  
Actual Operation ◽  
Multiple Unit ◽  
The Stability ◽  
Multi Body

Background: With the rapid development of the high-speed railway, the dynamic performance such as running stability and safety of the high-speed train is increasingly important. This paper focuses on the dynamic performance of high-speed Electric Multiple Unit (EMU), especially the dynamic characteristics of the bogie frame and car body. Various patents have been discussed in this article. Objective: To develop the Multi-Body System (MBS) model of EMU, verify whether the dynamic performance meets the actual operation requirements, and provide some useful information for dynamics and structural design of the proposed EMU. Methods: According to the technical characteristics of a typical EMU, a MBS model is established via SIMPACK, and the measured data of China high-speed railway is taken as the excitation of track random irregularity. To test the dynamic performance of the EMU, including the stability and safety, some evaluation indexes such as wheel-axle lateral forces, wheel-axle lateral vertical forces, derailment coefficients and wheel unloading rates are also calculated and analyzed in detail. Results: The MBS model of EMU has better dynamic performance especially curving performance, and some evaluation indexes of the stability and safety have also reached China’s high-speed railway standards. Conclusion: The effectiveness of the proposed MBS model is verified, and the dynamic performance of the MBS model can meet the design requirements of high-speed EMU.

Secretagogue-induced changes in subcellular Ca2+ distribution in isolated pancreatic acini

1981 ◽  
Vol 240 (2) ◽  
pp. G130-G140
Author(s):  
R. L. Dormer ◽  
J. A. Williams
Keyword(s):  
Atomic Absorption Spectrometry ◽  
High Speed ◽  
Microsomal Fraction ◽  
Absorption Spectrometry ◽  
Subcellular Fractionation ◽  
Differential Centrifugation ◽  
Zymogen Granules ◽  
Pancreatic Acini ◽  
Induced Changes ◽  
Stimulation Of

In a prior study, we demonstrated that pancreatic secretagogues increased both the uptake into and washout of 45Ca2+ from isolated mouse pancreatic acini. The net result of these processes was an initial fall in total acinar cell Ca2+ content. In the present study, we have employed subcellular fractionation of acini under conditions that minimized posthomogenization redistribution of Ca2+ in order to localize those organelles involved in intracellular Ca2+ fluxes. Homogenization and differential centrifugation of acini, preloaded with 45Ca2+ and subjected to a period of washout, showed that carbachol induced an increased loss of 45Ca2+ from all fractions isolated. The high-speed microsomal fraction lost 45Ca2+ to a greater extent than did whole acini; measurement of total Ca2+ by atomic absorption spectrometry showed a net loss of Ca2+ from this fraction. Purification of the lower-speed fractions indicated that carbachol increased 45Ca2+ exchange with both zymogen granules and mitochondria, but net Ca2+ levels in these organelles were unchanged. It was concluded that stimulation of pancreatic acini by carbachol results in the release of calcium from a microsomal compartment leading to a rise in cytoplasmic Ca2+, increased exchange with granule and mitochondrial Ca2+, and increased efflux of Ca2+ from the cell.

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