混凝土损伤演化的声发射区域定位

发布时间：2018-07-05 06:31

本文选题：混凝土 + 声发射　；参考：《燕山大学》2014年硕士论文

【摘要】：混凝土是最重要也是应用最广泛的建筑材料之一，它的损伤破裂过程一直是力学、土木工程、材料等各学科研究的热点和难点。混凝土的损伤演化是一个复杂的非线性演化过程，其破坏过程表现为微裂纹的萌生、发展、贯通直至最终失稳破坏。声发射技术是近年发展起来的一项动态无损检测技术，因其操作简单、灵敏度高、效果直观并可实时监测等优点，被广泛应用于材料的性能评价和损伤检测等领域。本文就是应用声发射技术对混凝土的裂纹扩展情况和破坏形态进行监测，对混凝土材料的损伤演化过程进行分析和研究。本文进行了混凝土材料的声发射性能研究，建立了混凝土材料内部损伤变化和声发射信号参数变化之间的联系。而后进行了单轴压缩试验，加载同时用声发射系统进行检测，比较不同骨料粒径和表面状态的混凝土试件在单轴压缩条件下的破坏过程和形态，分析声发射信号参数与宏观破坏过程的对应关系，，研究不同试件的声发射特征，从细观角度揭示混凝土损伤演化过程。本文进行了疲劳加载试验，根据对试验现象和声发射检测结果的观察，将混凝土疲劳破坏阶段进行分类。把试验所得的全部声发射信号参数进行分析和处理，总结不同骨料粒径和表面状态的混凝土试件在各个阶段的声发射特征和损伤演化规律。根据混凝土材料的损伤程度，对混凝土进行了分区描述，定义了混凝土材料的安全区、损伤区和破损区，对分区的声发射参数阀值标准进行了探讨。在此标准下，对混凝土材料破损区的产生条件进行研究。
[Abstract]:Concrete is one of the most important and widely used building materials. Its damage and rupture process has been a hot and difficult point in mechanics, civil engineering, materials and other disciplines. The damage evolution of concrete is a complex nonlinear evolution process, and the failure process is characterized by the initiation and development of microcracks, and the failure of concrete through and through to the ultimate instability. Acoustic emission (AE) is a dynamic nondestructive testing technology developed in recent years. Because of its advantages of simple operation, high sensitivity, intuitive effect and real-time monitoring, it is widely used in the field of material performance evaluation and damage detection. In this paper, the acoustic emission technique is used to monitor the crack growth and failure pattern of concrete, and the damage evolution process of concrete material is analyzed and studied. In this paper, the acoustic emission properties of concrete materials are studied, and the relationship between the changes of damage and acoustic emission signal parameters is established. Then uniaxial compression test was carried out, and the loading and acoustic emission system were used to detect the failure process and morphology of concrete specimens with different aggregate size and surface state under uniaxial compression. The relationship between the acoustic emission signal parameters and the macroscopic failure process is analyzed. The acoustic emission characteristics of different specimens are studied and the damage evolution process of concrete is revealed from the viewpoint of meso. In this paper, fatigue loading tests are carried out. According to the observation of the experimental phenomena and the results of acoustic emission testing, the fatigue failure stages of concrete are classified. All the acoustic emission signal parameters obtained from the test are analyzed and processed, and the acoustic emission characteristics and damage evolution laws of concrete specimens with different aggregate size and surface state are summarized. According to the damage degree of concrete material, the zone description of concrete is carried out, the safety zone, damage zone and damage zone of concrete material are defined, and the threshold standard of acoustic emission parameter is discussed. Under this standard, the producing conditions of the damaged zone of concrete material are studied.
【学位授予单位】：燕山大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TU528

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