Improvement of predictive testing with respect to crack propagation and wear of tyre treads

基于循环载荷下的理论和实验结果，在DFG研究单元597中设计了增强弹性体共混物的断裂力学和统计力学的新测试概念。拟议项目的目标是开发关于裂纹扩展的改进的预测测试概念，使其更接近轮胎部件的实际运行条件。这些新概念将与工业合作伙伴一起，针对具体应用进行有条不紊的验证和优化，特别是在越野卡车轮胎的磨损操作条件下的切屑和切割问题。通过载重子午线轮胎胎面样品的介电谱分析，应弄清硫化过程中的流动和松弛过程是否导致炭黑网络的显著各向异性，以及在持续载荷下炭黑网络的扩展修改是否有利于碎屑和切割现象。在597中开发的一种同时使用预缺口拉伸和纯剪切试件的改进的动态测试方法将转化为工业应用。将用一种新的光学在线分析方法来研究断裂过程和裂纹前沿的具体发展以及裂纹前沿附近的物理性质。撕裂疲劳分析仪的实验研究将得到应力软化的有限元分析和不同加载条件下撕裂能的计算的支持。

Based on theoretical and experimental results under cyclic loading, new testing concepts were designed within the DFG Research Unit 597 Fracture Mechanics and Statistical Mechanics of Reinforced Elastomer Blends. The objective of the proposed project is to develop improved concepts of predictive testing with respect to crack propagation that are closer to the real operating conditions of tyre parts. Together with industrial partners these new concepts will be validated and optimised methodically with regard to specific applications, i.e. especially the chip and cut problem at abrasive operating conditions in case of off-road truck tyres. By means of dielectric spectroscopy on truck tyre tread samples it should be clarified if flow and relaxation processes during vulcanisation lead to a pronounced anisotropy of the carbon black network and to which extend modifications of carbon black network under persistent loading favour the chip and cut phenomenon.An improved dynamic testing method developed within FOR 597 using simultaneously pre-notched tensile and pure shear specimens will be transferred to industrial application. The fracture processes and the specific development of the crack front as well as the physical properties in the vicinity of the crack front will be investigated by a new optical online-analysis.Experimental investigations with the Tear Fatigue Analyser will be supported by the finite element analysis of stress softening and calculations of the tearing energy at various loading conditions.