高应变率下新型纤维砂浆动态劈拉特性

Dynamic Splitting Tensile Properties of Mortar Mixed with New Fibers Subjected to High Strain Rate

采用分离式霍普金森压杆(SHPB)冲击试验,研究了超高分子聚乙烯(UHMWPE)纤维砂浆、聚乙烯醇(PVA)纤维砂浆试件的动态劈拉特性,阐述了纤维砂浆动态劈拉强度和动态增长因子的应变率效应;提出了静动态统一的纤维砂浆劈拉强度拟合公式;结合试件破坏形态和能量耗散,分析了纤维砂浆劈拉性能的优劣.结果表明:相对于PVA纤维砂浆,UHMWPE纤维砂浆抗拉增强效应更加突出;不同类型的PVA纤维砂浆动态力学性能存在明显差异;纤维砂浆动态劈拉强度、动态增长因子和能量耗散均随加载应变率增大而增长;相比素砂浆,掺1.8kg/m^3的UHMWPE纤维砂浆最大动力耗散能Ws,max大约提高15%.

Split Hopkinson pressure bar(SHPB)device was used to conduct the experimental study on the dynamic tensile properties of mortars mixed with ultra-high molecular weight polyethylene(UHMWPE)and polyvinyl alcohol(PVA)fibers.The effects of strain rate on dynamic splitting tensile strength and dynamic increase factors of specimens were analyzed and the fitting formula of uniform splitting tensile strength based on strain rate of fibrous mortar s static and dynamic load-bearing was proposed;combined with the failure mode and energy dissipation,the splitting tensile strength of fibrous mortar was analyzed.Test results show that,compared with the PVA fibrous mortar,impact tensile strengthening effect of UHMWPE fibrous mortar is prominent,also different types of PVA fibrous mortar has obvious difference on dynamic mechanical properties.Furthermore,the dynamic tensile strength,dynamic increase factor and energy dissipation of fibrous mortar increasing with the accelerating of strain rate,e.g.,the maximum dissipation energy W s,max is increased about 15%with 1.8 kg/m 3 UHMWPE fibrous mortar compared with the plain specimen.