论文部分内容阅读
本文通过改进的分离式Hopkinson压杆试验装置对聚丙烯纤维混凝土进行冲击压缩试验。对5种不同纤维掺量的混凝土进行了4个应变率的单轴冲击压缩试验。从已有的本构模型中选择最合适的来模拟聚丙烯纤维混凝土,并对本构方程进行了改进。自定义了一种损伤确定方式,并通过对比损伤因子来确定了应变、应变率及纤维掺量对损伤演化的影响,得出损伤演化最慢时的纤维掺量;应变率效应在峰值应力中体现得比较明显,但在初始弹性模量上却相差甚微;一定的纤维掺量可以增加材料的韧性,但是过多或者过少的掺量都会导致峰值应力减小。
In this paper, the impact compression test of polypropylene fiber reinforced concrete is carried out with the improved split Hopkinson pressure bar test equipment. Five kinds of concrete with different fiber content were subjected to four uniaxial impact compression tests. From the existing constitutive models, the most appropriate one is chosen to simulate the polypropylene fiber concrete, and the constitutive equation is improved. A method of determining the damage was defined. By comparing the damage factors, the influence of strain, strain rate and fiber content on the damage evolution was obtained. The fiber content at the slowest damage evolution was obtained. The strain rate effect was in the peak stress But the initial elastic modulus is quite different; a certain amount of fiber can increase the toughness of the material, but too much or too little amount will lead to the decrease of peak stress.