A. Rezvani, G. Karami and M. Yaghoubi,
Volume 20, Issue 1 (7-2001)
Abstract
One of the great enemies of rubber compounds is heat. Heat will cause chemical and physical degradation of vulcanized rubber as well as a considerable loss in its strength. A major source of heat generation in a tire is due to internal friction resulting from the viscoelastic deformation of the tire as it rolls along the road. Another source of heat generation in a tire is due to its contact friction with the road. Prediction of the temperature rise at different parts of the tire will help to detect the behavior of the tire as regards its strength and its failure.
In the present work, initially the data required for the thermal analysis of the tire are determined which include: the thermal conductivity of rubber compounds, the tire rolling resistance and its heat build-up rate. The thermomechanical analysis of a typical tire then follows based on the thermodynamics of an irriversible process. The mechanical dissipatives, i.e. the hystersis losses are assummed to be the major source of heat in the mathematical formulation.
A finite element code is developed for two-dimensional heat transfer analysis of the tire. The results obtained show that the highest temperature rise will occur on the carcass-tread interface in a tire specially at heavy loading and under high speed conditions.
Keywords: Heat Generation, Rubber, Contact Friction, Design, Finite Element, Viscoelastic Deformation
A. Zolriasatein, S. Navazani, M. Rezaei Abdadchi, N. Riahi Noori ,
Volume 39, Issue 3 (12-2020)
Abstract
In this paper, the effect of adding aluminum trihydrate (ATH) on electrical (including dielectric constant, dielectric loss and strength, volume and surface resistivity) and hydrophobic properties of two-part room temperature volcanized (RTV) silicone rubber resin coatings were investigated. For this purpose, the RTV-ATH nanocomposite was made by physical mixing and its electrical and hydrophobic properties were compared with those of pure RTV. The results showed an increase in the dielectric constant (from 3.11 to 4.13), the dielectric loss (by ~ 0.06) and the dielectric strength (by ~ 4 KV/mm) of the RTV-ATH composite compared to the pure RTV. Moreover, ATH increased volume resistivity and reduced the surface resistivity of composite coatings. On the other hand, by spraying of coatings, no improvement in the hydrophobicity class of composite coating compared to pure RTV was observed and both samples were standardized in the HC2 standard class. Structural analysis of samples was performed by X-ray diffraction, optical microscopy and scanning electron microscopy and the presence of the main phases in them was confirmed.
