不同尺寸橡胶/帘线H型拉拔试验界面参数的归一化处理评价方法

A normalized evaluation method on the interface parameters of rubber/cord pull-out tests for different sized samples

H型拉拔试验被广泛应用于橡胶/帘线复合材料界面粘结强度的估算.然而,目前的国际标准只要求在橡胶/帘线H型拉拔试验中记录拔出力的大小,并强调从不同尺寸的样品中获得的结果不具有可比性.在本文中,我们研究了不同尺寸橡胶/帘线试验样品的H拔出结果的可比性,并提出了一种归一化的评价方法来处理这些结果.分别对尺寸为5 mm、6.4 mm、10 mm的试验样品进行橡胶/帘线H拉拔试验(尺寸为7.5 mm、8.5 mm的试件结果作为支撑性试验).在试验结果的基础上,采用有限元法内聚单元模型对界面粘结强度进行了分析,所得出的内聚力参数比国际标准中所规定的拔出力更能准确地反映界面粘结性能.因此,采用内聚单元法能够更合理地比较不同橡胶/帘线试样的界面粘结强度.我们首先基于6.4 mm尺寸样品的试验结果建立有限元模型,并确定满足条件的内聚单元参数,然后将其应用于其他尺寸的样品模型.尽管试验样品的尺寸大小在变化,但在保持内聚单元参数不变的前提下,模拟结果与试验结果仍然保持良好的一致性,这表明内聚参数不受样本尺寸的影响.在此基础上,我们提出了一种归一化方法,使不同尺寸样品的橡胶/帘线H拉拔试验的结果具有了可比性.本文提出的归一化方法是对现有国际、国内标准实验方法的扩展.

H pull-out test is widely employed as a primary method for estimating the adhesion value of the interface in the rubber/cord composites.However,the current international standards only require to record the pull-out force in rubber/cord H pull-out tests,and emphasize that results obtained from samples of different sizes are not comparable.In this paper,we investigate the comparability of H pull-out results from rubber/cord samples of varying samples and propose an evaluation method to normalize these results.Rubber/cord H pull-out tests of samples with the sizes of 5 mm,6.4 mm,and 10 mm are undertaken respectively(the results of the specimens with dimensions of 7.5 mm and 8.5 mm are provided as supplementary information).Based on the test results,the adhesion values are analyzed by the model of cohesive elements in finite element method,and the cohesive parameters derived from these models are considered more accurate indicators of adhesion value than the pull-out force.Therefore,a more reasonable comparison of adhesion values becomes feasible.The cohesive parameters are initially determined using the 6.4 mm model and then applied to the other sample models.Good consistency can be seen between the simulations and the test results even though the sample sizes are changing,demonstrating that cohesive parameters remain unaffected by sample dimensions.Based on this,we develop a normalization method that enables the comparability of rubber/cord H pull-out results from samples of different sizes.The cohesive parameters provide a more accurate representation of the adhesion value,and the normalization method we propose serves as an extension of current experimental methods outlined in international standard.