Viscoelastic Material Calibration Procedure for Rolling Resistance Calculation

2019 ◽  
Vol 47 (3) ◽  
pp. 232-256
Author(s):  
Gabriel N. Curtosi ◽  
Pablo N. Zitelli ◽  
Jorge Kuster

ABSTRACT As tire engineers, the authors are interested in predicting rolling resistance using tools such as numerical simulation and tests. When a car is driven along, its tires are subjected to repeated deformation, leading to energy dissipation as heat. Each point of a loaded tire is deformed as it completes a revolution. Most energy dissipation comes from the cyclic loading of the tire, which causes the rolling resistance in addition to the friction force in the contact patch between the tire and road. Rolling resistance mainly depends on the viscoelastic energy dissipation of the rubber materials used to manufacture the tires. To obtain an accurate amount of dissipated energy, a good understanding of the material mathematical model and its behavior is mandatory. For this reason, a calibration procedure was developed. To obtain a good method for calculating rolling resistance, it is necessary to calibrate all rubber compounds of the tire at different temperatures and strain frequencies. Thus, to validate the calibration procedure, simulations were performed to evaluate the error between the tests and models at material sample and tire levels. For implementation of the calibration procedure in the finite element models of rolling tires, a procedure is briefly described that takes into account the change in properties caused by the temperature during the simulations. Linear viscoelasticity is used to model the properties of the materials and is found to be a suitable approach to tackle energy dissipation due to hysteresis for rolling resistance calculation.

2019 ◽  
Vol 48 (3) ◽  
pp. 224-248
Author(s):  
Pablo N. Zitelli ◽  
Gabriel N. Curtosi ◽  
Jorge Kuster

ABSTRACT Tire engineers are interested in predicting rolling resistance using tools such as numerical simulation and tests. When a car is driven along, its tires are subjected to repeated deformation, leading to energy dissipation as heat. Each point of a loaded tire is deformed as the tire completes a revolution. Most energy dissipation comes from the cyclic loading of the tire, which causes the rolling resistance in addition to the friction force in the contact patch between the tire and road. Rolling resistance mainly depends on the dissipation of viscoelastic energy of the rubber materials used to manufacture the tires. To obtain a good rolling resistance, the calculation method of the tire finite element model must take into account temperature changes. It is mandatory to calibrate all of the rubber compounds of the tire at different temperatures and strain frequencies. Linear viscoelasticity is used to model the materials properties and is found to be a suitable approach to tackle energy dissipation due to hysteresis for rolling resistance calculation.


Author(s):  
Mehmet Emin Arslan ◽  
Elif Ağcakoca ◽  
Merve Şentürk

Reinforced concrete structure systems are usually designed as frame or shear wall-frame systems. It is possible to reduce the deformation and displacement in the system by increasing the structural stiffness. Besides, large displacements on the floors caused by horizontal load are damped by the cracks in these walls. The present paper aims to examine the effects of materials used in the wall construction as well as thickness of the plaster on the behavior of infill walls under cyclic loads. In order to investigate the above mentioned effects, three Infill walls that were produced from three different materials namely, horizontal hollow bricks, pumice blocks and aerated concrete blocks were tested in three setups (without plaster, with 1 cm plaster and 2.5 cm plaster on it). In order to determine pure wall contribution, the infill walls were placed in a steel frame test set-up which was hinged from all four corners and were then exposed to cyclic loads taking into account the displacement controlled loading protocol proposed in FEMA 461. Right after applying the plaster to the infill walls, load carrying and energy dissipation capacities of the walls were examined comparatively. Load-displacement, backbone curve and cumulative dissipated energy curves of each infill walls are generated using the data collected from the experiments and the infill walls behaviors are graphically explained. Test results showed that existence and thickness of plaster significantly affected cyclic behavior of the test walls by increasing energy dissipation capacities and load carrying capacities.


1992 ◽  
Vol 65 (1) ◽  
pp. 78-106 ◽  
Author(s):  
K. A. Grosch

Abstract Sliding abrasion experiments reveal that the abrasion loss has to be expressed as a power function of the dissipated energy. Both the abrasion loss per unit energy dissipation and the power index depend on the compound and on the type of surface on which the experiment is being carried out. Hence the relative rating of a compound depends on pressure and on surface roughness. This nonlinear dependence on energy dissipation leads also to a rating dependence of slip of the wear of slipping wheels or the wear of tires. If the abrasion energy function for different compounds can be determined, then the wear ranking for different tires should be predictable using the slipping wheel theory. Experiments with tires running under controlled slip conditions show that this is not the case. Predictions differ even in ranking of compounds. Dissipation processes generate heat, so that temperature conditions in the contact area and their influence on the abrasion loss have to be considered in addition to mechanical rupture and fatigue. Laboratory experiments using slipping model wheels are being discussed which use testing conditions designed to generate different temperatures in the contact area. Compound rankings and ranking reversals are obtained which are in agreement with tire wear experiments under controlled slip conditions.


2021 ◽  
Vol 62 (4) ◽  
Author(s):  
Ulrich Mießner ◽  
Thorben Helmers ◽  
Ralph Lindken ◽  
Jerry Westerweel

Abstract In this study, we reconstruct the 3D pressure field and derive the 3D contributions of the energy dissipation from a 3D3C velocity field measurement of Taylor droplets moving in a horizontal microchannel ($$\rm Ca_c=0.0050$$ Ca c = 0.0050 , $$\rm Re_c=0.0519$$ Re c = 0.0519 , $$\rm Bo=0.0043$$ Bo = 0.0043 , $$\lambda =\tfrac{\eta _{d}}{\eta _{c}}=2.625$$ λ = η d η c = 2.625 ). We divide the pressure field in a wall-proximate part and a core-flow to describe the phenomenology. At the wall, the pressure decreases expectedly in downstream direction. In contrast, we find a reversed pressure gradient in the core of the flow that drives the bypass flow of continuous phase through the corners (gutters) and causes the Taylor droplet’s relative velocity between the faster droplet flow and the slower mean flow. Based on the pressure field, we quantify the driving pressure gradient of the bypass flow and verify a simple estimation method: the geometry of the gutter entrances delivers a Laplace pressure difference. As a direct measure for the viscous dissipation, we calculate the 3D distribution of work done on the flow elements, that is necessary to maintain the stationarity of the Taylor flow. The spatial integration of this distribution provides the overall dissipated energy and allows to identify and quantify different contributions from the individual fluid phases, from the wall-proximate layer and from the flow redirection due to presence of the droplet interface. For the first time, we provide deep insight into the 3D pressure field and the distribution of the energy dissipation in the Taylor flow based on experimentally acquired 3D3C velocity data. We provide the 3D pressure field of and the 3D distribution of work as supplementary material to enable a benchmark for CFD and numerical simulations. Graphical abstract


1931 ◽  
Vol 4 (3) ◽  
pp. 426-436
Author(s):  
K. J. Soule

Abstract Further work is very desirable on the effect of different accelerators, antioxidants, and fluxes. It is possible that their study will throw more light on the mechanism of the swelling phenomena, and also help to explain the anomalous behavior of some of the fillers tested. It would also seem to be worth while to study the action of a few selected stocks in water, at several temperatures between room temperature and 100° C., to determine if the water absorption and swelling merely increase with rising temperatures, or whether there might be an actual change in behavior at different temperatures.


2018 ◽  
Vol 44 ◽  
pp. 00167
Author(s):  
Jarosław Sowiński ◽  
Adam Hofman ◽  
Marek Dziubiński

The practical application of the model of water supply network realized in the program Epanet 2 requires the calibration of the model. The proposed simple calibration procedure, allows for taking into account the changes in resistance caused by the aging process, to be substituted by resistance coefficient K. In order to determine the substitute resistance coefficient K, the fire hydrant flow tests could be used, which allows to determine the aging for a given material. Calibration of the water supply network model is shown on the example of a small urban network in central Poland..


2018 ◽  
Vol 86 (1) ◽  
Author(s):  
A. Louhghalam ◽  
M. Tootkaboni ◽  
T. Igusa ◽  
F. J. Ulm

A major contributor to rolling resistance is road roughness-induced energy dissipation in vehicle suspension systems. We identify the parameters driving this dissipation via a combination of dimensional analysis and asymptotic analysis. We begin with a mechanistic model and basic random vibration theory to relate the statistics of road roughness profile and the dynamic properties of the vehicle to dissipated energy. Asymptotic analysis is then used to unravel the dependence of the dissipation on key vehicle and road characteristics. Finally, closed form expressions and scaling relations are developed that permit a straightforward application of the proposed road-vehicle interaction model for evaluating network-level environmental footprint associated with roughness-induced energy dissipation.


1978 ◽  
Vol 1 (16) ◽  
pp. 129 ◽  
Author(s):  
Ole Secher Madsen ◽  
Paisal Shusang ◽  
Sue Ann Hanson

In a previous paper Madsen and White (1977) developed an approximate method for the determination of reflection and transmission characteristics of multi-layered, porous rubble-mound breakwaters of trapezoidal cross-section. This approximate method was based on the assumption that the energy dissipation associated with the wave-structure interaction could be considered as two separate mechanisms: (1) an external, frictional dissipation on the seaward slope; (2) an internal dissipation within the porous structure. The external dissipation on the seaward slope was evaluated from the semi-theoretical analysis of energy dissipation on rough, impermeable slopes developed by Madsen and White (1975). The remaining wave energy was represented by an equivalent wave incident on a hydraulically equivalent porous breakwater of rectangular cross-section. The partitioning of the remaining wave energy among reflected, transmitted and internally dissipated energy was evaluated as described by Madsen (1974), leading to a determination of the reflection and transmission coefficients of the structure. The advantage of this previous approximate method was its ease of use. Input data requirements were limited to quantities which would either be known (water depth, wave characteristics, breakwater geometry, and stone sizes) or could be estimated (porosity) by the design engineer. This feature was achieved by the employment of empirical relationships for the parameterization of the external and internal energy dissipation mechanisms. General solutions were presented in graphical form so that calculations could proceed using no more sophisticated equipment than a hand calculator (or a slide rule). This simple method gave estimates of transmission coefficients in excellent agreement with laboratory measurements whereas its ability to predict reflection coefficients left a lot to be desired.


2019 ◽  
Vol 86 (9) ◽  
Author(s):  
Mansour Alturki ◽  
Rigoberto Burgueño

This paper presents a new energy dissipation system composed of multistable cosine-curved domes (CCD) connected in series. The system exhibits multiple consecutive snap-through and snap-back buckling behavior with a hysteretic response. The response of the CCDs is within the elastic regime and hence the system's original configuration is fully recoverable. Numerical studies and experimental tests were conducted on the geometric properties of the individual CCD units and their number in the system to examine the force–displacement and energy dissipation characteristics. Finite element analysis (FEA) was performed to simulate the response of the system to develop a multilinear analytical model for the hysteretic response that considers the nonlinear behavior of the system. The model was used to study the energy dissipation characteristics of the system. Experimental tests on 3D printed specimens were conducted to analyze the system and validate numerical results. Results show that the energy dissipation mainly depends on the number and the apex height-to-thickness ratio of the CCD units. The developed multilinear analytical model yields conservative yet accurate values for the dissipated energy of the system. The proposed system offered reliable high energy dissipation with a maximum loss factor value of 0.14 for a monostable (self-recoverable) system and higher for a bistable system.


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