钢纤维混凝土动态拉伸与数值模拟

发布时间：2018-01-13 22:07

本文关键词：钢纤维混凝土动态拉伸与数值模拟　出处：《广州大学》2013年硕士论文　论文类型：学位论文

【摘要】：面对当前越来越多无法预测的自然灾害的变化,对高性能建筑材料的要求越来越高,为了加强建筑工程的安全性,提高建筑结构混凝土动态冲击、抗震抗风性能是极为重要的关键。基于此目的,本文对钢纤维混凝土动态拉伸力学性能进行了一系列实验与相关理论研究,主要内容如下：一、采用分离式霍普金森压杆分别对含钢纤维体积率为0、2%、3%的混凝土试块进行动态劈拉试验,测出其动态劈拉强度是静态劈拉强度的1.22-1.51倍,比不含钢纤维的混凝土试块提高了41.60%和68.22%。试验结果还表明：当钢纤维含量越高,其裂缝的数量和尺度越小,断裂面的钢纤维被拔出,而不是钢纤维本身的强度不够被拔断。本章建立了钢纤维混凝土动态劈拉强度与基体的关系以及钢纤维混凝土劈拉强度与子弹冲击速度之间的关系式。二、采用有限元方法,对SFRC进行了动态冲击劈裂数值模拟,将其在高速冲击条件下的内力瞬态变化、破坏形式和特征直观的用计算机展现出来,分别从改变应变率的大小和混凝土强度着手对比,并分析其区别,验证了试验得到的结论：第一,应变率的提高可以增大混凝土动态抗拉强度；第二,随着混凝土强度的提高,对动态冲击作用抵抗能力越强,为进一步了解研究其抗冲击破坏特性提供了参考。三、综合实验结果和模拟现象,对SFRC开裂过程中能量的耗散进行了研究探索,汇总分析了各参数对断裂模型的影响,并将混凝土能量耗散原理运用到钢纤维混凝土结构设计中,推导了能量在结构设计中的弯矩表示,将SFRC的动态性能与实际工程应用紧密结合起来。
[Abstract]:In the face of changes in the current increasingly unpredictable natural disasters, the high performance building materials have become increasingly demanding, in order to strengthen the safety of construction, improve the concrete building structure dynamic impact, seismic and wind performance is the key. Based on this purpose, this paper on the tensile mechanical properties of steel fiber reinforced concrete is a dynamic a series of experiments and theoretical research, the main contents are as follows:
First, using the split Hopkinson pressure bar of steel fiber volume ratio is 0,2%, the 3% concrete block dynamic splitting test, test the dynamic splitting tensile strength is 1.22-1.51 times than the static tensile strength, without steel fiber concrete specimens increased 41.60% and 68.22%. test results also show that when the the steel fiber content is high, the number and scale of the crack is small, the fracture surface of the steel fiber is pulled out, rather than the strength of steel fiber is not enough to be pulled off.
In this chapter, the relationship between the dynamic splitting strength of steel fiber reinforced concrete and the matrix, and the relationship between the splitting tensile strength of steel fiber concrete and the impact velocity of the bullet are established in this chapter.
Two, using the finite element method, the dynamic impact of SFRC splitting in the numerical simulation, under the high-speed impact force transient changes, failure form and intuitive features by computer show, respectively, to contrast from the size change of the strain rate and the strength of concrete, and analyze the difference between test results verified conclusion: first, the increasing of the strain rate can increase the dynamic tensile strength of concrete; second, with the increase of concrete strength, the dynamic impact resistance ability is stronger, in order to further understand the impact of failure to provide a reference.
Three, the comprehensive experimental results and the simulation of SFRC cracking phenomenon, the dissipation of energy in the process of study, we analyzed the effects of various parameters on the fracture model, and the concrete energy dissipation principle is applied to the design of steel fiber concrete structure, derived energy said in the structure design of the moment, the dynamic performance and practical application of SFRC closely together.

【学位授予单位】：广州大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TU528

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