基于小波分析的混凝土超声波缺陷检测方法研究

发布时间：2018-03-20 15:08

本文选题：超声波　切入点：缺陷检测　出处：《武汉纺织大学》2013年硕士论文　论文类型：学位论文

【摘要】：随着社会发展，我们对混凝土这种被普遍利用的建筑材料的品质要求也渐渐提升，混凝土的配料、搅拌、以及成型和养护等工作的进行一般是在建筑工地和搅拌站等.然而，由于随着其强度的提升，构件面积逐渐变小，导致如果中间个别构件出现毛病，就会对整个混凝土的质量产生不利影响，以至于产生一系列不可预测的事故或者出现建筑方面的安全隐患。经调查发现，在中国大型水库中的40%的大坝都出现了不同程度的安全问题，中小型水库的36%的大坝也出现各种各样的病险问题。随着危险例如裂缝，甚至坍塌等情况的加重。80年代之后就开始引起了国家的重视，政府组织开始有目的的，有规律的对大坝出现的各种安全问题进行勘察。并且发现在这些危险的背后，混凝土的质量问题起着决定性作用。于是，长期以来，严格控制管理混凝土质量问题，成了国家、社会、以及教育，尤其是建筑学教育中不可忽视的并得到广泛研究的一个热门话题。本文首先对超声波检测的发展做了一个较全面的论述，并介绍了超声波检测基本原理以及超声波在介质中的传播特点。介绍了统计学方法、PSD判据法在作为缺陷判定方法时的使用方法，根据缺陷性质、体积大小与PSD判据的关系，建立了缺陷为夹层、空洞、以及蜂窝或其它介质填充等几种PSD临界判定表达式，并根据各测点实测PSD判据与PSD临界值进行比较来判定缺陷。再引入小波，，运用冲击回波法检测裂缝深度，通过对采集到的信号进行小波变换，提取反映裂缝缺陷的有效特征信息。最后总结分析了超声波缺陷检测方法中还需进一步研究讨论的问题。
[Abstract]:With the development of society, the quality requirements of concrete, a widely used building material, have been gradually raised. The ingredients, mixing, molding and maintenance of concrete are generally carried out at construction sites and mixing stations. As its strength increases, the area of the component becomes smaller, leading to a negative impact on the quality of the whole concrete if a fault occurs in the intermediate individual component. As a result of a series of unpredictable accidents or building safety risks, the investigation found that 40% of the dams in China's large reservoirs had different degrees of safety problems. The 36% dams of small and medium-sized reservoirs also have a variety of dangerous problems. As the risks such as cracks and even collapses became more serious. After the 1980s, the government began to pay attention to them, and government organizations began to have a purpose. Investigate regularly the various safety problems that arise in the dam. And find that behind these dangers, the quality of concrete plays a decisive role. So, for a long time, it has become a country to strictly control and manage the quality of concrete. Society, as well as education, especially architectural education, can not be ignored and widely studied as a hot topic. In this paper, the development of ultrasonic testing is discussed in a comprehensive way. The basic principle of ultrasonic testing and the propagation characteristics of ultrasonic wave in medium are introduced. The method of using statistical method as a defect determination method is introduced. According to the relationship between defect property, volume and PSD criterion, Several kinds of PSD critical determination expressions such as sandwich, cavity, honeycomb or other media filling are established, and the defects are determined by comparing the measured PSD criterion with the critical value of PSD. The crack depth is detected by the impact echo method, and the effective characteristic information reflecting the crack defect is extracted by wavelet transform of the collected signal. Finally, the problems that need to be further studied and discussed in ultrasonic defect detection methods are summarized and analyzed.
【学位授予单位】：武汉纺织大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TU528.07

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