EPDM包覆层材料准静态压缩实验及力学模型研究

Quasi-Static Compression Experiment and Research on

关键词:  包覆材料  本构模型  应变率  超弹模型  压缩实验

Key words:  Insulation material  Constitutive model  Strain rate  Hyperelastic model  Compression experiments

摘要:

三元乙丙(Ethylene Propylene Diene Monomer，即EPDM)材料的力学性能对使用其作为包覆层的固体火箭发动机起到关键的作用。利用万能试验机进行EPDM包覆层材料常温下的准静态压缩实验，通过实验发现，EPDM包覆层材料具有明显的超弹特性和率敏感特性。提出采用超弹模型来描述材料压缩变形下的力学性能，通过比较Mooney-Rivlin模型、Ogden模型和Polynomial模型的拟合结果，发现二阶Polynomial超弹模型的精度最高，故选取Polynomial超弹模型作为EPDM包覆层材料的本构模型，并考虑其率相关特性，拟合超弹及率相关两部分的材料参数。对比实验结果，发现压缩模型能很好地预测40%应变内的EPDM材料的力学性能。

Abstract:

The mechanical property of the EPDM material used as insulation was significant for the solid rocket motor. The quasi-static uniaxial compression experiments of EPDM insulation material have been carried out by universal testing machine under the normal temperature. The experimental results show that EPDM insulation material was hyperelastic and sensitive to the strain rate. The most suitable model is chosen as the constitutive model of the EPDM insulation material by comparing Mooney-Rivlin model，Ogden model and Polynomial model. The accuracy of second Polynomial hyperelastic model was the highest. Considering that the material was obviously sensitive to the strain rate，the two parts material parameters of hyperelastic and rate related are fitted. Compared with the experimental results，the compression model can be effective to describe the mechanical behaviors of EPDM material within 40% strain.