轮胎超弹性本构材料参数确定的影响因素分析

轮胎橡胶超弹性本构模型材料参数的准确确定对车辆轮胎设计理论具有重要意义。首先研究国内外超弹性本构模型参数确定中常用的理论计算流程和试验方法，并回顾常用的几种确定本构关系材料参数的应力应变曲线。通过对橡胶材料硫化程度、疲劳试验次数、加卸载顺序等因素对橡胶材料性能的影响研究，对车辆轮胎超弹性本构模型参数确定方法进行探讨，发现橡胶材料的力学性能不仅取决于其承受的峰值载荷，而且很大程度上取决于载荷的施加顺序。基于橡胶弹性物理学理论，通过分析比较，确定轮胎力学分析中用于本构模型参数拟合的试验曲线选取原则：首先应确定所研究的轮胎橡胶材料的实际硫化程度；再结合考察轮胎实际运行工况，通过试验或者数值仿真技术确定材料加载历程中经历的最大峰值载荷；采用该载荷峰值下的橡胶材料循环特性曲线作为材料本构关系曲线来拟合相应材料参数。循环次数采用3万次可满足精度要求；从提高试验效率出发，也可采用定载荷下7次循环后稳定的力学曲线。

Influence Factors for Material Parameters Determination of Hyperelastic Constitutive Model of Vehicle Tire Rubber

The definition accuracy of hyperelastic constitutive model material parameters of tyre rubber is significant for vehicle tire design. Current theory and test methods for the material definition are studied, and several popular stress-strain curves for determining the material parameters are reviewed. Through the research of the influence of some factors, such as rubber cure state, fatigue cycle numbers, and load & unloading sequence, on the rubber properties, the material definition method is discussed. It is found that the mechanical properties of rubber are not only related to the withstand peak load, but also to a large extend related to the load applied sequence. Based on the rubber elasticity theory and through comparison and investigation, the principle of selecting the experimental curves used for the fitting of constitutive model parameters in the mechanical analysis of tire is determined. Firstly, the actual cure state of test tire rubber should be evaluated. Secondly, based on the actual running condition of tire, through test or numerical simulation technique, the max peak load experienced by the material in the loading sequence is determined. At last, rubber cycle curves at the peak load are .adopted as the constitutive relation curves of material to fit the corresponding material parameters. 30 000 cycle numbers in the test can meet the accuracy requirement. is proved valid, although 7 cycle numbers can be optional if test effeciency is highlighted.