Temperature Gradients in Tire Rubber Can Reduce/Increase Tensile Stresses and Hence Wear and Fatigue

It has been known for some time that grading of the elastic modulus (namely, softer in the surface) leads to a significant reduction in tensile stresses due to contact loadings; this has been studied mostly to suppress the cracking of brittle materials. In particular, a recent study has demonstrated...

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Main Authors: Jean-Emmanuel Leroy, Michele Ciavarella
Format: Article
Language:English
Published: MDPI AG 2025-06-01
Series:Lubricants
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Online Access:https://www.mdpi.com/2075-4442/13/7/294
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author Jean-Emmanuel Leroy
Michele Ciavarella
author_facet Jean-Emmanuel Leroy
Michele Ciavarella
author_sort Jean-Emmanuel Leroy
collection DOAJ
description It has been known for some time that grading of the elastic modulus (namely, softer in the surface) leads to a significant reduction in tensile stresses due to contact loadings; this has been studied mostly to suppress the cracking of brittle materials. In particular, a recent study has demonstrated that the effect is most pronounced for a large Poisson’s ratio, as is the case for incompressible materials. Grading of the modulus occurs intrinsically in viscoelastic materials like rubber when there is a temperature gradient within the rubber, which leads to significant changes of tensile stresses, affecting fatigue and wear. Friction and wear have been analyzed experimentally in the past with respect to mean temperature, revealing an ideal range of temperature with the highest friction and lowest wear, but the effect of the temperature gradient is not as well understood. The present paper presents a simple model of a sinusoidal wave of pressure and shear traction moving on a viscoelastic half-plane (standard material) at constant velocity, finding an approximate solution for a linear variation of viscosity across the depth. We find that tensile stresses may be very significantly altered by temperature changes of a few degrees only across the depth equal to the wavelength of the loading wave. In particular, they are reduced if the temperature decreases with depth, with beneficial effects for fatigue and wear.
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spelling doaj-art-edcc9cbebf454e3388343903485ea58e2025-08-20T03:08:09ZengMDPI AGLubricants2075-44422025-06-0113729410.3390/lubricants13070294Temperature Gradients in Tire Rubber Can Reduce/Increase Tensile Stresses and Hence Wear and FatigueJean-Emmanuel Leroy0Michele Ciavarella1Institute of Mechanics, Technical University Berlin, Straße des 17. Juni 135, 10623 Berlin, GermanyDMMM Department, Politecnico di Bari, Viale Gentile 182, 70126 Bari, ItalyIt has been known for some time that grading of the elastic modulus (namely, softer in the surface) leads to a significant reduction in tensile stresses due to contact loadings; this has been studied mostly to suppress the cracking of brittle materials. In particular, a recent study has demonstrated that the effect is most pronounced for a large Poisson’s ratio, as is the case for incompressible materials. Grading of the modulus occurs intrinsically in viscoelastic materials like rubber when there is a temperature gradient within the rubber, which leads to significant changes of tensile stresses, affecting fatigue and wear. Friction and wear have been analyzed experimentally in the past with respect to mean temperature, revealing an ideal range of temperature with the highest friction and lowest wear, but the effect of the temperature gradient is not as well understood. The present paper presents a simple model of a sinusoidal wave of pressure and shear traction moving on a viscoelastic half-plane (standard material) at constant velocity, finding an approximate solution for a linear variation of viscosity across the depth. We find that tensile stresses may be very significantly altered by temperature changes of a few degrees only across the depth equal to the wavelength of the loading wave. In particular, they are reduced if the temperature decreases with depth, with beneficial effects for fatigue and wear.https://www.mdpi.com/2075-4442/13/7/294graded materialsviscoelasticitytemperature gradientstress statesliding line contactfriction
spellingShingle Jean-Emmanuel Leroy
Michele Ciavarella
Temperature Gradients in Tire Rubber Can Reduce/Increase Tensile Stresses and Hence Wear and Fatigue
Lubricants
graded materials
viscoelasticity
temperature gradient
stress state
sliding line contact
friction
title Temperature Gradients in Tire Rubber Can Reduce/Increase Tensile Stresses and Hence Wear and Fatigue
title_full Temperature Gradients in Tire Rubber Can Reduce/Increase Tensile Stresses and Hence Wear and Fatigue
title_fullStr Temperature Gradients in Tire Rubber Can Reduce/Increase Tensile Stresses and Hence Wear and Fatigue
title_full_unstemmed Temperature Gradients in Tire Rubber Can Reduce/Increase Tensile Stresses and Hence Wear and Fatigue
title_short Temperature Gradients in Tire Rubber Can Reduce/Increase Tensile Stresses and Hence Wear and Fatigue
title_sort temperature gradients in tire rubber can reduce increase tensile stresses and hence wear and fatigue
topic graded materials
viscoelasticity
temperature gradient
stress state
sliding line contact
friction
url https://www.mdpi.com/2075-4442/13/7/294
work_keys_str_mv AT jeanemmanuelleroy temperaturegradientsintirerubbercanreduceincreasetensilestressesandhencewearandfatigue
AT micheleciavarella temperaturegradientsintirerubbercanreduceincreasetensilestressesandhencewearandfatigue