thermo-mechanical analysis of stationary rolling tires

在第一个资助期内开发的热机械轮胎模型将被一个详细的滞回损失模型所扩展，滞回损失是由胎面橡胶与粗糙表面的局部粗糙接触造成的。这些研究活动的动机是假设软非弹性胎面橡胶与粗糙路面的粗糙接触所产生的耗散效应对轮胎的总滚动损失有一定的贡献。在第一个工作包中，将开发用于详细研究软橡胶与粗糙路面接触的有限元模型。为简便起见，将道路描述为刚体；粗糙度将通过光谱描述建模。对于胎面橡胶，将假设在第一个资助期内得到的复杂的热-力学非弹性本构模型。研究了轮胎在典型工况下的热力学响应。基于这些细观长度尺度的详细研究，将推导出宏观模拟的本构接触律。建立一个表面自由能密度函数，由此可以导出表面牵引力和相关的切线算子。由于粗糙接触的物理性质，我们将不遵循将法向接触和切向接触分离为优先级的经典概念。此外，还建立了一个耗散函数，由此可以推导出粗糙接触中由于非弹性效应而产生的整体热量。这些函数的参数，如路面纹理特征和道路温度，将从第一步进行的详细接触调查中确定。在第三个工作包中，开发的本构接触定律将用于静止滚动轮胎的宏观模拟。本研究的目的是提供一种强大的仿真技术，用于研究不同装配部件对静止滚动轮胎总滚动损失的贡献。

The thermo-mechanical tire model developed during the first funding period shall be extended by a detailed model for the hysteretic loss which results from the local asperity contact of the tread rubber with the rough surface. These research activities are motivated by the hypothesis that the dissipative effects caused by the asperity contact of the soft inelastic tread rubber with the rough road surface causes a mentionable contribution to the total rolling loss of tires. In a first working package finite element models for detailed studies of the contact of soft rubber with rough road surfaces will be developed. The road is described as rigid body for simplicity; the rough-ness will be modeled via a spectral description. For the tread rubber the sophisticated thermo-mechanical inelastic constitutive models derived in the first funding period will be assumed. The ther-mo-mechanical response will be studied under tire typical operational conditions. Based on these detailed studies at the mesoscopic length-scale a constitutive contact law for macro-scopic simulations shall be derived. A surface free energy density function will be developed from which the surface traction and the related tangent operators can be derived. Motivated by the physics of the asperity contact we will not follow the classical concept that splits normal and tangential contact traction a priory. In addition a dissipation function will be developed, from which the global heat production due to the inelastic effects in the asperity contact can be derived. The parameters for these functions, e.g. road surface texture characteristics and road temperature, will be identified from the detailed contact investigations performed in step one. In a third working package the developed constitutive contact laws will be implemented for a macro-scopic simulation of stationary rolling tires. Goal of this research is to provide a powerful simulation technique which enables studies on the contribution of different assembly parts to the total rolling loss of stationary rolling tires.