Abstract: In order to study the impact of initial damage of the material on the mechanical properties，quasi-static mechanical tests of EPDM were conducted and the distribution regularity of effective test results was obtained by analyzing the test results statistically. A constitutive model which is capable of expressing the initial defects of EPDM was built by introducing the random damage variable to Ogden model. The test results fall in a confidence interval with a confidence level of 90% estimated by the extended model，with a probability of 94%. The proposed model has excellent estimation results for mechanical properties of EPDM inhibitor with initial defects.

Key words: Initial defect；Random variable；Statistical regularity；Constitutive model；Uniaxial tension；EPDM

摘要： 为了研究材料初始缺陷对其力学行为的影响，针对三元乙丙(EPDM)包覆层材料进行准静态力学实验，并且采用统计学方法对实验结果进行分析，获取以随机损伤参数函数表示的有效实验结果的分布规律，通过引入随机损伤参数函数扩展Ogden模型，建立能够描述EPDM初始缺陷的本构方程。结果表明:实验结果以94%的概率落入该扩展模型所估计的置信程度为90%的置信区间，该模型对于考虑初始缺陷的EPDM包覆层材料的力学行为预测结果较好。

关键词: 初始缺陷；随机变量；统计规律；本构模型；单轴拉伸；三元乙丙