分级持荷对混凝土动态抗弯拉特性的研究

发布时间：2018-06-05 01:52

本文选题：混凝土 + 分级持荷　；参考：《河北工业大学》2015年硕士论文

【摘要】：混凝土是用途最广的建筑材料之一,在当代的构筑物和建筑物中,所发挥的作用越来越关键。混凝土在工程结构中受力状态不仅包含静荷载,还包含动荷载。近些年,混凝土静态力学的相关性能有了很大程度的完善,而动态力学性能的研究成果仍然存在很大的提升空间,尤其是混凝土经历历史荷载后动态抗弯拉力学性能的研究。对于经历了不同历史强度荷载的混凝土而言,混凝土动态力学性能的研究就尤为重要。本文利用MTS加载装置模拟混凝土结构可能受到的动态荷载,配合使用动静态数据采集仪,并对前人的成果进行借鉴与总结,采用适当的试件制作方法和加载工艺,对强度为C40、C45、C50的混凝土试件,在应变速率分别为10-6/s、10-5/s、10-4/s时,进行动态直接破坏和分级加载持荷两种不同受力情况的动态弯拉破坏,来研究应变速率和分级持荷对混凝土动态抗弯拉力学性能和变形性能(抗弯拉强度、弹性模量、泊松比、峰值应变)的影响,根据试验过程和相应的试验结果,进而探究混凝土的抗弯拉破坏机理。通过分析试验所得数据,可知:当应变速率为定值时,分级持荷后,混凝土的动态抗弯拉强度和弹性模量都有一定幅度的降低,峰值应变则有一定幅度的增高;在分级持荷一定的条件下,随着应变速率的提高,混凝土的抗弯拉强度也均有提高,其中弹性阶段的泊松比基本处在0.2左右。
[Abstract]:As one of the most widely used building materials, concrete plays a more and more important role in modern structures and buildings. The stress state of concrete in engineering structure includes not only static load, but also dynamic load. In recent years, the correlation of static mechanics of concrete has been improved to a great extent, but the research results of dynamic mechanical properties still have great improvement space, especially the study of dynamic flexural and tensile mechanical properties of concrete after the historical load. The study of dynamic mechanical properties of concrete is particularly important for concrete with different historical strength. In this paper, the MTS loading device is used to simulate the dynamic load of concrete structure, the dynamic and static data acquisition instrument is used, and the previous achievements are used for reference and summary. For concrete specimens with a strength of C40 / C45 / C50, when the strain rate is 10 ~ (-6) / s ~ (-5) / s ~ (-10 ~ (-4) respectively, dynamic direct failure and dynamic flexural failure under different loading conditions are carried out. To study the effect of strain rate and graded load on the dynamic flexural tensile properties and deformation properties of concrete (flexural tensile strength, elastic modulus, Poisson's ratio, peak strain). Then the bending and tensile failure mechanism of concrete is explored. Through the analysis of the test data, it can be seen that when the strain rate is constant, the dynamic flexural tensile strength and elastic modulus of concrete will decrease to a certain extent, and the peak strain will increase by a certain extent. With the increase of strain rate, the flexural tensile strength of concrete also increases under the condition of graded load, and the Poisson's ratio of elastic stage is about 0.2.
【学位授予单位】：河北工业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU528

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