A Transient Tire Model for Uneven Road Surface

Author(s):  
Seongho Kim ◽  
Parviz E. Nikravesh ◽  
Gwanghun Gim

This study presents a transient tire model for tire vibration characteristics due to uneven road surfaces. The model is composed of two parts—a static circular beam and a dynamic rigid ring. A new contact algorithm is developed based on the circular beam model, which can estimate contact pressure distribution by solving a set of linear equations. Tire vibration characteristics are then represented by combining the rigid ring model to the circular beam. Examples of contact pressure distribution and tire transient behaviors due to cleat tests are demonstrated and compared with measured data.

1983 ◽  
Vol 11 (1) ◽  
pp. 50-63 ◽  
Author(s):  
J. T. Tielking

Abstract A finite element tire model, based on nonlinear shell of revolution elements, has been developed to investigate tire-pavement interaction. The basic characteristics of this relatively comprehensive model are reviewed here, with attention focused on its ability to calculate the effect of tire design variables on tire performance data. A four-ply bias tire is used to show the ability of the model to predict the different effects that nylon and polyester cords have on tire deformation, contact pressure distribution, and traction.


Author(s):  
Yatheendhar D. Manicka ◽  
Ashok D. Belegundu

Abstract The contact pressure between a poppet valve and its seat is an important consideration for valve performance. The geometry of the contacting surfaces is optimized to acheive maximum uniformity in the contact pressure distribution. A general contact algorithm for point-to-cubic sliding contact is presented and verified. It is then used to optimize the valve geometry. The poppet valve and seat are modeled as axisymmetric components.


2006 ◽  
Vol 34 (2) ◽  
pp. 100-118 ◽  
Author(s):  
N. Miyashita ◽  
K. Kabe

Abstract An analytical tire model for cornering force (CF) and self-aligning torque (SAT) is described on the basis of the Fiala model. CF and SAT come mainly from the shear stress and sliding friction at the tread/road interface. The CF and SAT variations also change the kinetic conditions for their own generations, that is, the contact-pressure distribution, the tire-part deformation, and the relative position of the steering axis within the contact patch. The present model, the CF/SAT system model, which includes these conditional changes through the CF and SAT feedback loops, approximates the slip-angle dependence of CF and SAT with high accuracy. The inverse data analysis, that is, least-squares fittings of the measured data to the model, give some experimental information about the tread friction coefficient (the adhesive and sliding friction coefficient) and the variation in contact-pressure distribution during cornering. The CF/SAT system model, as well as the CP/SATP model in Part I, may be useful for both the tire production at tire makers and the vehicle dynamics simulation at car makers.


2020 ◽  
Author(s):  
Zhiming Zhang ◽  
Jun Zhang ◽  
Yapeng Shang ◽  
Tong Zhang

Abstract The endplates are essential to assembly a large proton exchange membrane (PEM) fuel cell stack, whose deflection is negative to its uniform contact pressure distribution and large electrical contact resistance. The endplates with assembly clamping belts are proposed as an equivalent mechanical beam model consisting of elastic beam element with clamping forces. The deflection curve equations of endplates with 1 to 5 clamping belts are studied which allows investigating endplates deflection for uniform contact pressure distribution. Based on this equivalent mechanical model for fuel cell stack, the effects of the thicknesses of endplates, numbers and positions of clamping belts are discussed, and show the optimal thickness of endplate with different clamping belts, and moreover the optimal position of intermediate and outer clamping belts on the endplates. Finally, a three-dimensional finite element analysis (FEA) of a fuel cell stack clamping with steel belts and nonlinear contact elements is compared to what the equivalent mechanical beam model predicts. It is found that the presented model gives good prediction accuracy for the deflection behavior of endplates and the clamping force. Results showed that the equivalent mechanical modeling is effective and helpful for the design of a large fuel cell stack assembly.


2006 ◽  
Vol 34 (1) ◽  
pp. 38-63 ◽  
Author(s):  
C. Lee

Abstract A tire slips circumferentially on the rim when subjected to a driving or braking torque greater than the maximum tire-rim frictional torque. The balance of the tire-rim assembly achieved with weight attachment at certain circumferential locations in tire mounting is then lost, and vibration or adverse effects on handling may result when the tire is rolled. Bead fitment refers to the fit between a tire and its rim, and in particular, to whether a gap exists between the two. Rim slip resistance, or the maximum tire-rim frictional torque, is the integral of the product of contact pressure, friction coefficient, and the distance to the wheel center over the entire tire-rim interface. Analytical solutions and finite element analyses were used to study the dependence of the contact pressure distribution on tire design and operating attributes such as mold ring profile, bead bundle construction and diameter, and inflation pressure, etc. The tire-rim contact pressure distribution consists of two parts. The pressure on the ledge and the flange, respectively, comes primarily from tire-rim interference and inflation. Relative contributions of the two to the total rim slip resistance vary with tire types, depending on the magnitudes of ledge interference and inflation pressure. Based on the analyses, general guidelines are established for bead design modification to improve rim slip resistance and mountability, and to reduce the sensitivity to manufacturing variability. An iterative design and analysis procedure is also developed to improve bead fitment.


1995 ◽  
Vol 23 (2) ◽  
pp. 116-135 ◽  
Author(s):  
H. Shiobara ◽  
T. Akasaka ◽  
S. Kagami ◽  
S. Tsutsumi

Abstract The contact pressure distribution and the rolling resistance of a running radial tire under load are fundamental properties of the tire construction, important to the steering performance of automobiles, as is well known. Many theoretical and experimental studies have been previously published on these tire properties. However, the relationships between tire performances in service and tire structural properties have not been clarified sufficiently due to analytical and experimental difficulties. In this paper, establishing a spring support ring model made of a composite belt ring and a Voigt type viscoelastic spring system of the sidewall and the tread rubber, we analyze the one-dimensional contact pressure distribution of a running tire at speeds of up to 60 km/h. The predicted distribution of the contact pressure under appropriate values of damping coefficients of rubber is shown to be in good agreement with experimental results. It is confirmed by this study that increasing velocity causes the pressure to rise at the leading edge of the contact patch, accompanied by the lowered pressure at the trailing edge, and further a slight movement of the contact area in the forward direction.


1995 ◽  
Vol 23 (1) ◽  
pp. 26-51 ◽  
Author(s):  
S. Kagami ◽  
T. Akasaka ◽  
H. Shiobara ◽  
A. Hasegawa

Abstract The contact deformation of a radial tire with a camber angle, has been an important problem closely related to the cornering characteristics of radial tires. The analysis of this problem has been considered to be so difficult mathematically in describing the asymmetric deformation of a radial tire contacting with the roadway, that few papers have been published. In this paper, we present an analytical approach to this problem by using a spring bedded ring model consisting of sidewall spring systems in the radial, the lateral, and the circumferential directions and a spring bed of the tread rubber, together with a ring strip of the composite belt. Analytical solutions for each belt deformation in the contact and the contact-free regions are connected by appropriate boundary conditions at both ends. Galerkin's method is used for solving the additional deflection function defined in the contact region. This function plays an important role in determining the contact pressure distribution. Numerical calculations and experiments are conducted for a radial tire of 175SR14. Good agreement between the predicted and the measured results was obtained for two dimensional contact pressure distribution and the camber thrust characterized by the camber angle.


1995 ◽  
Vol 23 (4) ◽  
pp. 238-255 ◽  
Author(s):  
E. H. Sakai

Abstract The contact conditions of a tire with the road surface have a close relationship to various properties of the tire and are among the most important characteristics in evaluating the performance of the tire. In this research, a new measurement device was developed that allows the contact stress distribution to be quantified and visualized. The measuring principle of this device is that the light absorption at the interface between an optical prism and an evenly ground or worn rubber surface is a function of contact pressure. The light absorption can be measured at a number of points on the surface to obtain the pressure distribution. Using this device, the contact pressure distribution of a rubber disk loaded against a plate was measured. It was found that the pressure distribution was not flat but varied greatly depending upon the height and diameter of the rubber disk. The variation can be explained by a “spring” effect, a “liquid” effect, and an “edge” effect of the rubber disk. Next, the measurement and image processing techniques were applied to a loaded tire. A very high definition image was obtained that displayed the true contact area, the shape of the area, and the pressure distribution from which irregular wear was easily detected. Finally, the deformation of the contact area and changes in the pressure distribution in the tread rubber block were measured when a lateral force was applied to the loaded tire.


1992 ◽  
Vol 65 (4) ◽  
pp. 241-249
Author(s):  
Shigeru KAGAMI ◽  
Takashi AKASAKA ◽  
Atsushi HASEGAWA

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