环氧树脂玻璃钢的动静态拉伸力学特性

Dynamic and Static Tensile Mechanical Properties of Glass Fiber Reinforced Plastics

为系统地研究环氧树脂玻璃钢在静、动态拉伸载荷作用下的力学性能,采用材料测试系统和分离式霍普金森拉杆对材料进行拉伸试验,获得0.001~0.1 s^(-1)及1 128~1 840 s^(-1)应变率下的应力-应变曲线和相应的力学参数。结果表明,动态加载下环氧树脂玻璃钢的应变率增强效应较为明显。为此,引入动态增强因子描述环氧树脂玻璃钢在高应变率下力学性能的增强。采用扫描电镜对损伤断面进行观测,发现动态加载下纤维束平整断裂,而非静态加载下纤维拔出失效。相较于静态加载,动态拉伸载荷作用下玻璃钢的基体-纤维界面断裂韧度更高。基于环氧树脂玻璃钢在动态拉伸下的力学响应,引入宏观损伤累积量,建立一种考虑损伤的非线性拉伸本构模型。拟合结果表明,该模型整体上可以反映环氧树脂玻璃钢在动态拉伸载荷作用下的力学响应。

To systematically study the mechanical properties of glass fiber reinforced plastics,the stressstrain curves and corresponding mechanical parameters of glass fiber reinforced plastic with strain rates of 0.001–0.1 s^(-1) and 1 128–1 840 s^(-1) were obtained by material testing system(MTS) and split Hopkinson tensile bar(SHTB).The results show that the glass fiber reinforced plastic exhibits significant strain rate strengthening effect under dynamic loading.Therefore,the dynamic increasing factor was introduced to describe the strengthening effect of strain rate on mechanical properties of glass fiber reinforced plastics.Scanning electron microscopy(SEM) was used to observe and analyze the damaged section,and it was found that the fiber bundle was flatly fracture under dynamic loading,rather than failed by pulling out under static loading.In addition,the results show that the fracture toughness of the fiber-matrix interface under dynamic tensile loading is higher than that under static loading.Finally,based on the dynamic tensile mechanical response of glass fiber reinforced plastic,a nonlinear tensile constitutive model considering damage was established by introducing the macroscopic damage accumulation.Compared with the experimental results,the model as a whole can be used to characterize the dynamic tensile mechanical response of glass fiber reinforced plastic.