普通混凝土多轴动态性能试验研究

发布时间：2018-06-08 15:55

本文选题：混凝土 + 多轴　；参考：《大连理工大学》2013年博士论文

【摘要】：混凝土是现代建筑中被广泛应用的建筑材料。动态荷载(如地震、冲击、爆炸、车辆荷载、海浪荷载、风荷载等)能够造成建筑物和构筑物的破坏甚至倒塌,造成财产和生命的损失。混凝土结构的动力复杂受力分析是结构设计中的难点,例如框架结构的节点、核安全壳、混凝土拱坝等处于复杂应力状态的结构。我国处于环太平洋与欧亚地震带之间,是地震多发国家。现有的混凝土多轴动态性能研究成果中,单轴动态性能研究比较多,多轴动态性能研究比较少；爆炸、冲击荷载作用下混凝土性能研究比较多,地震荷载作用下(应变率范围10-5s-1-10-2s-1)混凝土性能研究比较少。因此,地震荷载作用下,多轴应力状态下混凝土的动态性能研究具有非常重要的意义。本文采用大连理工大学研制的三轴静、动液压伺服试验机,开展了一系列的混凝土单轴和多轴动态试验。应力组合方式包括：单轴压、单轴拉、定侧压双轴抗压、双轴比例抗压、双轴拉压和三轴抗压；应变率分别为：10-5s-1、10-4s-1、10-3s-1和10-2s-1。利用ABAQUS提供的用户自定义材料模块,编写了混凝土内时损伤动态破坏模型程序,建立了与本文部分试验相应的数值模型,进行了数值计算。主要研究内容如下： 1开展了混凝土单轴抗压、单轴抗拉动态性能试验,获得了试件的破坏形态,单轴压、拉动态强度,峰值荷载处的应变,单轴抗压峰值荷载处的割线模量,得到了单轴抗压、单轴抗拉强度与应变率的关系,获得了不同应变率下的单轴抗压、单轴抗拉应力-应变曲线。 2开展了定侧压双轴抗压和双轴比例抗压动态性能试验,获得了试件的破坏形态、双轴抗压动态强度和竖向峰值应变；获得了竖向荷载引起的侧向峰值应变、由竖向荷载引起的泊松比；讨论了比例加载与非比例加载两种加载方式对混凝土双轴抗压强度的影响；探讨了混凝土双轴受压强度提高的机理；从侧向变形的角度解释了双轴抗压强度随中间主应力变化的原因；建立了考虑应变率影响的混凝土双轴抗压动态破坏准则。 3开展了定围压三轴抗压动态性能试验,获得了试件的破坏形态、三轴抗压动态强度和竖向峰值应变;得到了三轴抗压动态强度的计算公式；比较了竖向单调加载和竖向循环加载时混凝土的三轴抗压强度；研究了定围压三轴抗压动态荷载下混凝土的能量耗散和混凝土的损伤。 4开展了定侧拉双轴拉压动态性能试验,获得了试件的破坏形态、双轴拉压动态强度和拉、压方向上的峰值应变。得到了双轴拉压强度及峰值应变随侧拉应力和应变率的变化规律。建立了考虑应变率影响的双轴拉压动态破坏准则。 5建立了在单轴、二轴及三轴应力状态下,应变率范围为10-5s-1-10-2s-1的八面体应力空间的混凝土动态破坏准则。为了工程上的实用性,给出了拉、压子午线的上限值、下限值和平均值。 6在本文建立的多轴动态强度破坏准则和内时损伤动态本构模型的基础上,利用ABAQUS中的用户自定义材料模块(UMAT),建立了与本文试验相应的数值模型并进行了数值计算,验证了自定义混凝土材料模型与本文试验结果是吻合的。
[Abstract]:Concrete is a widely used building material in modern architecture. Dynamic loads (such as earthquake, impact, explosion, vehicle load, sea wave load, wind load, etc.) can cause damage or even collapse of buildings and structures, and cause loss of property and life. The dynamic analysis of dynamic force of concrete structures is a difficult point in structural design, such as frame. The joints of the frame structure, the nuclear containment, the concrete arch dam and so on are in the complex stress state. China is located between the Pacific and Eurasian seismic zones, and it is an earthquake prone country. In the existing research results of the dynamic performance of concrete multi axis, there are many studies on the dynamic performance of the single axis, the dynamic performance of multi axis is relatively few, the explosion and the impact load are made. There is a lot of research on the performance of concrete under the action of seismic load (strain rate range 10-5s-1-10-2s-1) of concrete. Therefore, it is very important to study the dynamic performance of concrete under multi axis stress condition under seismic load.
In this paper, a series of uniaxial and multi axis dynamic tests of concrete are carried out by the three axis static and dynamic hydraulic servo testing machine developed by Dalian University of Technology. The stress combination methods include uniaxial compression, uniaxial tension, fixed side pressure biaxial compression, biaxial compression, biaxial tension and three axis compression, and the strain rate is 10-5s-1,10-4s-1,10-3s-1 and 10, respectively. -2s-1. uses the user custom material module provided by ABAQUS to write the dynamic damage model program of the concrete internal time damage, and establishes the numerical model corresponding to the part of this paper, and the numerical calculation is carried out.
The main contents are as follows:
1 a single axial compression and uniaxial tensile dynamic performance test was carried out. The failure form of the specimen, the single axial compression, the tensile dynamic strength, the strain at the peak load, the secant modulus at the peak load at the peak load were obtained, and the relationship between uniaxial compression, uniaxial tensile strength and strain rate was obtained, and the uniaxial compression and uniaxial compression at different strain rates were obtained. Tensile stress strain curve.
2 the dynamic performance test of double axial compression compression and double axial compression is carried out. The failure form, the dynamic strength and the vertical peak strain of the specimen are obtained. The lateral peak strain caused by the vertical load and the Poisson's ratio caused by the vertical load are obtained, and the mixing of two kinds of loading and non proportional loading methods are discussed. The effect of the double axial compressive strength of the soil is discussed, and the mechanism of the double axial compression strength of concrete is discussed. The cause of the change of the double axial compressive strength with the intermediate principal stress is explained from the angle of lateral deformation, and the dynamic failure criterion of the concrete biaxial compression is established considering the effect of the strain rate.
3 the dynamic performance test of the fixed confining pressure three axis compression is carried out. The failure form of the specimen, the compressive dynamic strength of the three axis and the vertical peak strain are obtained. The calculation formula of the dynamic strength of the three axis compression compression is obtained. The compressive strength of the concrete at the time of vertical monotonous loading and vertical cyclic loading is compared, and the constant confining pressure three axial compression dynamics is studied. Energy dissipation of concrete and damage of concrete under load.
4 the dynamic performance test of the double axial tension and pressure is carried out. The failure form of the specimen, the dynamic strength of the double axis tension and pressure and the peak strain in the direction of tension and pressure are obtained. The variation of the tensile strength and peak strain of the double axis with the lateral tensile stress and the strain rate are obtained. The dynamic failure criterion of the double axial tension and pressure considering the effect of the strain rate is established.
5 the dynamic failure criterion of concrete under the stress state of the single axis, two axis and three axis and the strain rate range of 10-5s-1-10-2s-1 is established in the eight face stress space. For practical engineering, the upper limit, lower limit and average value of the tension and pressure meridian are given.
6 on the basis of the multi axis dynamic strength failure criterion and the internal time damage dynamic constitutive model established in this paper, using the user defined material module (UMAT) in ABAQUS, a numerical model corresponding to this experiment is established and the numerical calculation is carried out. It is verified that the custom concrete material model is in agreement with the experimental results.
【学位授予单位】：大连理工大学
【学位级别】：博士
【学位授予年份】：2013
【分类号】：TU528

【参考文献】