An Analytical Model for the Transient Rolling Resistance Behavior of Tires

1999 ◽  
Vol 27 (3) ◽  
pp. 161-175 ◽  
Author(s):  
W. V. Mars ◽  
J. R. Luchini
Keyword(s):  
Steady State ◽  
Current Model ◽  
Rolling Resistance ◽  
Test Results ◽  
State Test ◽  
Steady State Rolling ◽  
Fuel Economy Standard ◽  
Transient Rolling ◽  
Arbitrary Velocity ◽  
Velocity History

Abstract The rolling resistance of tires has received increased attention as automakers and consumers seek to improve fuel economy. Standard rolling resistance tests are currently performed to characterize steady state rolling resistance. The transient rolling resistance behavior is also of interest, but requires more elaborate and more expensive testing. This paper presents a theory to predict the transient response of rolling resistance to changes in velocity, from empirical data generated at steady state. The current model neglects the effect of changes in inflation pressure. A general relationship is derived for an arbitrary velocity history. The special case for instantaneous velocity histories is investigated. The model is then compared with experimental results. Finally, we use the model to predict transient rolling resistance results for coast down testing, and a simulated urban driving cycle. The model provides a simple and effective way to determine transient tire rolling resistance from steady state test results. This may reduce the need for transient testing in the future.

Thermal Hydraulic Test of Advanced Fuel Bundle With Spectral Shift Rod (SSR) for BWR: Steady State and Transient Test Results and Analysis

2012 ◽  
Author(s):  
Takao Kondo ◽  
Kazuaki Kitou ◽  
Masao Chaki ◽  
Yukiharu Ohga ◽  
Takeshi Makigami
Keyword(s):  
Steady State ◽  
Water Level ◽  
Simulation Analysis ◽  
Spectral Shift ◽  
Test Results ◽  
Analysis Method ◽  
Fuel Bundle ◽  
State Test ◽  
Shift Effect ◽  
Steady State Test

Japanese national project of next generation light water reactor (LWR) development started in 2008. Under this project, spectral shift rod (SSR) is being developed. SSR, which replaces conventional water rod (WR) of boiling water reactor (BWR) fuel bundle, was invented to enhance the BWR’s merit, spectral shift effect for uranium saving. In SSR, water boils by neutron and gamma-ray direct heating and water level is formed as a boundary of the upper steam region and the lower water region. This SSR water level can be controlled by core flow rate, which amplifies the change of average core void fraction, resulting in the amplified spectral shift effect. This paper presents the steady state test with varied SSR geometry parameters, the transient test, and the simulation analysis of these steady state and transient tests. The steady state test results showed that the basic functioning principle such as the controllability of SSR water level by flow rate was maintained in the possible range of geometry parameters. The transient test results showed that the change rate of SSR water level was slower than the initiating parameters. The simulation analysis of steady state and transient test showed that the analysis method can simulate the height of SSR water level and its change with a good agreement. As a result, it is shown that the SSR design concept and its analysis method are feasible in both steady state and transient conditions.

scholarly journals Effect of Temperature on Material Properties of Carbon Fiber Reinforced Polymer (CFRP) Tendons: Experiments and Model Assessment

Materials ◽  
2019 ◽  
Vol 12 (7) ◽  
pp. 1025 ◽  
Author(s):  
Fei Zhou ◽  
Jiwen Zhang ◽  
Shoutan Song ◽  
Dong Yang ◽  
Chao Wang
Keyword(s):  
Steady State ◽  
Material Properties ◽  
Elevated Temperatures ◽  
Transient State ◽  
Fiber Reinforced Polymer ◽  
Test Results ◽  
Concrete Members ◽  
Frp Composites ◽  
Reinforced Polymer ◽  
State Test

Material properties at elevated temperatures are important factors in the fire safety design and numerical analysis of concrete members strengthened with fiber reinforced polymer (FRP) composites. Most of the previous research mainly focused on tensile strength and elastic modulus in conventional steady state temperature tests. However, the transient state test method is more realistic for strengthening concrete structures. At the same time, the coefficient of thermal expansion of FRP composites is also one of the important factors affecting concrete members at elevated temperatures. This paper presents a detailed experimental investigation on the longitudinal thermal expansion deformation, and the mechanical properties of carbon FRP (CFRP) tendons with 8 mm diameter in the steady state and transient state. The results indicate that longitudinal deformation of CFRP tendons is negative at high temperature; in addition, the transient state test results of CFRP tendons are slightly higher than the steady state test results. The final part of this paper assesses the accuracy of different empirical models. Furthermore, a new equation calculating the properties of CFRP composites at elevated temperatures is presented with the numerical fitting technique, which is in good agreement with the experimental results.

Modeling Transient Rolling Resistance of Tires3

2007 ◽  
Vol 35 (2) ◽  
pp. 118-140 ◽  
Author(s):  
John R. Luchini ◽  
James A. Popio
Keyword(s):  
Experimental Error ◽  
Rolling Resistance ◽  
Model Parameters ◽  
Test Results ◽  
Test Conditions ◽  
Model Predictions ◽  
The Matrix ◽  
Transfer Parameters ◽  
Equilibrium Test ◽  
Transient Rolling

Abstract The transient rolling resistance of several tires is predicted from the behavior of each tire on an equilibrium test. The objective of the study was to determine if model predictions would fall within the lab-to-lab experimental error described in the J-2452 test standard. The model used for this study, to predict the results of J-2452 from J-1269 data, was presented in Ref. [1]. The study used data from one tire to establish the model parameters. Then those parameters were used with tire and rolling resistance measurements from 12 other tires of another size. These tires were from four samples of each of three different tire constructions (tread patterns) and manufacturer. The reasons for the differences between the predictions and the test results were investigated and two significant sources of error were identified. First, the simplistic assumption that one set of heat-transfer parameters would apply to all tires was found to be inadequate. Second, the matrix of test conditions and regression model in J-1269, which must be used to extrapolate to the test conditions of J-2452, is inadequate. The modeling work in this article also found some of the details of the test protocols that may have significant effects on reported rolling resistance.

A Method for Comparing Transient NOx Emissions With Weighted Steady State Test Results

1998 ◽  
Author(s):  
David M. Swain ◽  
Cleophas C. Jackson ◽  
Christian E. Lindhjem ◽  
George J. Hoffman
Keyword(s):  
Steady State ◽  
Nox Emissions ◽  
Test Results ◽  
State Test ◽  
Steady State Test

Analysis of Temperature Distribution in a Rolling Tire Due to Strain Energy Dissipation

1997 ◽  
Vol 25 (3) ◽  
pp. 214-228 ◽  
Author(s):  
H. C. Park ◽  
S-K. Youn ◽  
T. S. Song ◽  
N-J. Kim
Keyword(s):  
Steady State ◽  
Temperature Distribution ◽  
Rolling Resistance ◽  
Thermomechanical Behavior ◽  
Finite Element Models ◽  
Heat Sources ◽  
Sequential Approach ◽  
Internal Dissipation ◽  
Steady State Rolling ◽  
Viscoelastic Theory

Abstract This paper addresses a systematic procedure using a sequential approach for the analysis of the coupled thermomechanical behavior of a steady state rolling tire. Not only knowledge of mechanical stresses but also knowledge of the temperature loading in a rolling tire are very important because material damage and material properties are affected significantly by the temperature. In general, the thermomechanical behavior of a pneumatic tire is a highly complex transient phenomenon that requires the solution of a dynamic nonlinear coupled thermoviscoelasticity problem with heat sources resulting from internal dissipation and friction. In this paper, a sequential approach, with effective calculation schemes, to modeling this system is presented to predict the temperature distribution with reasonable accuracy in a steady state rolling tire. This approach has three major analysis modules: deformation, dissipation, and thermal modules. In the dissipation module, an analytic method for the calculation of the heat source in a rolling tire is established using viscoelastic theory. For the verification of the calculated temperature profiles and rolling resistance at different velocities, they are compared with measured ones. Also, discussed are the accuracies of the linear and quadratic finite element models used in the analysis.

A Consistent Implementation of Inelastic Material Models into Steady State Rolling

2016 ◽  
Vol 44 (3) ◽  
pp. 174-190 ◽  
Author(s):  
Mario A. Garcia ◽  
Michael Kaliske ◽  
Jin Wang ◽  
Grama Bhashyam
Keyword(s):  
Steady State ◽  
Numerical Simulations ◽  
Viscoelastic Material ◽  
Rolling Contact ◽  
Arbitrary Lagrangian Eulerian ◽  
Ale Formulation ◽  
Inelastic Material ◽  
Material Formulation ◽  
Steady State Rolling ◽  
Efficient Alternative

ABSTRACT Rolling contact is an important aspect in tire design, and reliable numerical simulations are required in order to improve the tire layout, performance, and safety. This includes the consideration of as many significant characteristics of the materials as possible. An example is found in the nonlinear and inelastic properties of the rubber compounds. For numerical simulations of tires, steady state rolling is an efficient alternative to standard transient analyses, and this work makes use of an Arbitrary Lagrangian Eulerian (ALE) formulation for the computation of the inertia contribution. Since the reference configuration is neither attached to the material nor fixed in space, handling history variables of inelastic materials becomes a complex task. A standard viscoelastic material approach is implemented. In the inelastic steady state rolling case, one location in the cross-section depends on all material locations on its circumferential ring. A consistent linearization is formulated taking into account the contribution of all finite elements connected in the hoop direction. As an outcome of this approach, the number of nonzero values in the general stiffness matrix increases, producing a more populated matrix that has to be solved. This implementation is done in the commercial finite element code ANSYS. Numerical results confirm the reliability and capabilities of the linearization for the steady state viscoelastic material formulation. A discussion on the results obtained, important remarks, and an outlook on further research conclude this work.

Fidelity of J1269 and J24523

2007 ◽  
Vol 35 (2) ◽  
pp. 94-117 ◽  
Author(s):  
James A. Popio ◽  
John R. Luchini
Keyword(s):  
Steady State ◽  
Rolling Resistance ◽  
Test Methods ◽  
The Other ◽  
Reference Condition ◽  
Test Standards

Abstract This study compares data from the two Society of Automotive Engineers test methods for rolling resistance: J-2452 (Stepwise Coast-Down) and J-1269 (Equilibrium) steady state. The ability of the two methods to evaluate tires was examined by collecting data for 12 tires. The data were analyzed and the data showed that the two methods ranked the tires the same after the data were regressed and the rolling resistance magnitude was calculated at the Standard Reference Condition. In addition, analysis of the two methods using this matched set of testing provided an opportunity to evaluate each of these test standards against the other. It was observed that each test has merits absent from the other.

Prediction of Tire Tread Wear with FEM Steady State Rolling Contact Simulation

2003 ◽  
Vol 31 (3) ◽  
pp. 189-202 ◽  
Author(s):  
D. Zheng
Keyword(s):  
Weight Loss ◽  
Steady State ◽  
Cross Section ◽  
Rolling Contact ◽  
Dynamic Simulations ◽  
Element Analysis ◽  
Vehicle Acceleration ◽  
Steady State Rolling ◽  
Driving Conditions ◽  
Rate Profile

Abstract A procedure based on steady state rolling contact Finite Element Analysis (FEM) has been developed to predict tire cross section tread wear profile under specified vehicle driving conditions. This procedure not only considers the tire construction effects, it also includes the effects of materials, vehicle setup, test course, and driver's driving style. In this algorithm, the vehicle driving conditions are represented by the vehicle acceleration histogram. Vehicle dynamic simulations are done to transform the acceleration histogram into tire loading condition distributions for each tire position. Tire weight loss rates for different vehicle accelerations are generated based on a steady state rolling contact simulation algorithm. Combining the weight loss rate and the vehicle acceleration histogram, nine typical tire loading conditions are chosen with different weight factors to represent tire usage conditions. It is discovered that the tire tread wear rate profile is changing continuously as the tire is worn. Simulation of a new tire alone cannot be used to predict the tire cross-section tread wear profile. For this reason, an incremental tread wear simulation procedure is performed to predict the tire cross section tread wear profile. Compared with actual tire cross-section tread wear profiles, good results are obtained from the simulations.

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