短纤维增强三元乙丙薄膜拉伸破坏率相关Tsai-Hill强度准则

Rate dependent Tsai-Hill strength criterion for short fiber reinforced EPDM film in tensile failure process

短纤维增强三元乙丙(EPDM)薄膜材料是一种应用于固体火箭发动机装药的新型绝热结构材料,其密度小、耐烧蚀且力学性能良好。基于正交各向异性单向板的Tsai-Hill强度准则,引入率相关函数法和率强度因子法改进,预测材料在不同偏轴方向下的抗拉强度,从而建立一种适用于准静态条件下的率相关各向异性通用准则。研究表明:轴向强度和抗剪强度随应变率的增加而增加;相比于率强度因子法,基于率相关函数法的TsaiHill强度准则对材料抗拉强度的预测精度较高;率强度因子法预测抗拉强度的误差与参考速率的选取和率强度因子的函数表达式有关。

Short fiber reinforced ethylene propylene diene monomer（EPDM）film material is a new type of thermal insulation and structural materials,which is applied in the cladding of solid rocket motor with low density,ablative resistance and good mechanical properties.In order to establish a general criterion for rate dependent anisotropy in quasi-static conditions,rate dependent function and rate intensity factor methods were introduced to extend Tsai-Hill strength criterion,which was used to predict the tensile strength in different off-axis directions.Studies show that axial strength and shear strength increase with the strain rate.Compared with rate intensity factor method,TsaiHill strength criterion based on rate dependent function method has higher prediction accuracy.Meanwhile,the prediction error of rate intensity factor method has strong relations with selection of reference rate and function expression of rate intensity factor.