【作者】 王丽娜；

【导师】 苏幼坡；

【作者基本信息】 河北理工大学 ， 结构工程， 2010， 硕士

【摘要】 一般来说,由于混凝土是弹塑性材料,当应变率较低时,混凝土对应变率不敏感,当应变率增大时,混凝土对应变率的敏感程度随之增加。因此,探索应变率对混凝土对本构关系的影响对于工程实际具有十分重要应用价值。对混凝土进行了动态单轴抗压试验,并根据实验结果,建立了考虑应变率影响下的本构模型。研究的目标是通过系统全面的试验研究和理论分析,建立适合C20~C35等级混凝土的考虑应变速率影响的单轴压应力—应变本构关系,为混凝土结构分析提供理论依据。通过大量的试验,研究不同加载速率对不同强度混凝土的抗压强度、受压弹性模量、泊松比、峰值应变和应力—应变全曲线的影响规律,给了出考虑应变速率影响的混凝土单轴受压的应力—应变曲线方程。采集设备采用美国Iotech公司高速便携式测试系统,用于高速动态振动应变信号测量。论文主要研究以下内容:1)分析了测定混凝土轴压应力一变形全曲线的前提条件,研制出一套刚度和加载能力均较大的试验装置,测得应力—应变全曲线。2)分析了影响混凝土轴压应力一变形全曲线结果的主要因素。通过试验表明,应变率对混凝土应力—应变曲线、泊松比、峰值应变、极限应变和弹性没有影响,只对混凝土抗压强度有影响。更多还原

【Abstract】 Generally, concrete is a elastic-plastic material. When the strain rate is low, the concrete is not sensitive to the strain rate. With the strain rates increasing, the sensitivity of concrete is increasing. Therefore, the exploration of the behavior of uniaxial loaded concrete under high compression rates on the constitutive relation is very important for practical engineering.The dynamic axially compression experiments of concrete are carried. According to those results, the model of uniaxial loaded concrete under high compression rates have been built.Through systematic and comprehensive experimental study and theoretical analysis, the effects of strain rates are considered, and stress–strain constitutive relation of C20 ~ C35 concrete under uniaxial compression is established. The work have provides a theoretical basis for analysis of concrete structures. Rule of the different loading rates on the different strength of concrete compressive strength, modulus of elasticity in compression, Poisson ratio, critical strain and stress–strain curves under different strain rates are studed through a large number of tests, uniaxial compression stress-strain curve equations under different strain rates are given. The collecting device is the U.S. Iotech’s high-speed portable test system. It is used to measure high-speed of dynamic vibration response signals. The main work and some conclusions are as follows:1 ) The premise of measuring stress–strain curve for concrete is analyzed theoretically. The device has been revised to raise its rigidity. The device has higher rigidity and greater load range.2)In order to make stress–strain curve more precise, the factors which affect the result of mesuring are analyzed theoretically.Through a large number of tests, loading rates have no effect on stress–strain curves, Poisson ratio, critical strain and modulus of elasticity. Loading rates only have an effect on compressive strength.更多还原