A hybrid experimental-computational approach is proposed for frictional characterization of elastomers and elastomeric composites. An axisymmetric indentor is pressed into a thick slab of elastomer and resistance to the indentor's axial torsion is experimentally measured. Similar numerical analysis is performed based on FEA to predict the same torsional resistance due to friction at contact surface. Finally, unknown frictional properties are statistically evaluated by matching the corresponding experimental and numerical predictions of the torque under different levels of compression, angular speed, etc. Implementation of the approach is shown for representative elastomeric materials, where coefficient of friction (COF) is analyzed as a nonlinear function of contact pressure and approximated by a polynomial series. The effect of angular speed on frictional properties is experimentally observed and quantified in a simple form. The generalization of the approach, accounting for the effect of friction on contact pressure, is proposed in the form of an iterative procedure. The sensitivity of COF on contact pressure is experimentally observed.

A new experimental method and corresponding analytical model were proposed to characterize cut, chip and chunk wear for elastomeric materials. According to the model, the wear is considered as a time-dependent nonlinear process. Experimental verification of the proposed model was conducted for four typical elastomers. It was shown that the amount of wear loss may be accurately described by the model, based on two independent material parameters. The effect of each parameter on cut, chip and chunk wear resistance was analyzed in detail. High statistical reliability was shown for the proposed material parameters and corresponding analytical predictions. The proposed method may be recommended as a robust predictor of cut, chip and chunk wear processes for rubber and, potentially, other polymer materials.

Existing methods to analyze the hysteretic behavior of elastomers are primarily based on a deterministic point of view, ignoring scatter of material properties. To overcome this limitation, a probabilistic model is proposed to describe random hysteretic energy loss of viscoelastic materials under two-or three-dimensional (2-or 3-D) cyclic loading. The model takes into consideration the random nature of material properties along with a significant nonlinearity of deformation. Simple analytical solutions to predict major statistical characteristics of random energy loss (mean values, standard deviations) are offered. A generalization of the 3-D model is proposed, where cyclic functions of loading may be different in different directions. A problem of experimental characterization of random material properties is systematically considered on examples of two representative elastomers.

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В статье рассмотрена оптимизированная кластерная версия пакета конечноэлементного моделирования, использованная в проекте «Разработка вычислительноинформационных технологий компьютерного моделирования на параллельных вычислительных комплексах травматологических и операционных процессов для оперативной выработки диагностических и лечебных рекомендаций», выполняемом в рамках федеральной целевой программы «Исследования и разработки по приоритетным направлениям развития научно-технологического комплекса России на 2007-2012 годы» по Государственному контракту от 30 сентября 2009 года 02.514.11.4121.Ключевые слова: математическое моделирование, метод конечных элементов, кластерные системы, параллельное программирование.