塔机材料常规缺陷的声发射信号特性的实验分析

发布时间：2018-01-02 22:15

本文关键词：塔机材料常规缺陷的声发射信号特性的实验分析　出处：《东北大学》2012年硕士论文　论文类型：学位论文

【摘要】：随着建筑塔式起重机(塔机)的广泛应用,国内外每年都因起重作业造成大量的财产损失和人身伤亡事故。危险源的在线定位与检测是塔机安全评估与事故预防的关键。由于金属构件长时间承受交变载荷的作用,会在主要承受应力集中区,构件变截面区,焊缝与母材熔合线之间等部位产生疲劳裂纹,成为诱发重大安全事故的隐患。因此,针对上述缺陷的无损检测研究具有重要的理论意义和工程价值。声发射技术具有效率高、检验周期短、对活性缺陷敏感等优点,目前在压力容器、航空航天等行业的检测已取得了成功应用。由于塔机工作现场声发射信号获取的复杂性和材料的声发射源参数特性缺乏典型样本,基于声发射技术的塔机无损检测研究目前还处于探索阶段。本文利用SDAES数字声发射检测仪,针对塔机钢材常规缺陷所制备的实验试件,进行声发射源的模式识别与信号参数特征提取,论文具体研究内容如下： (1)通过资料分析,确定塔式起重机钢结构的常见缺陷形式,并根据这些缺陷形式人工制备了Q235母材、表面裂纹及焊接缺陷试件； (2)掌握声发射仪器的使用方法及声发射原理,以声发射仪使用方式和声发射原理为依据,制定合理的实验方案及分析方法,同时用实验方法测量了声发射信号在Q235材料的传播速度； (3)进行加载试验,采集母材试件、表面裂纹和焊接缺陷试件在不同载荷下的声发射信号,并实时监测声发射源的产生和变化； (4)再通过声发射信号参数分析软件对所采集的AE信号进行定位特性分析,声发射信号参数特性分析,声发射信号频谱特性分析,最后总结出Q235母材及带有缺陷试件的典型声发射信号主要特征参数的分布范围样本。
[Abstract]:With the construction of the tower crane (crane) is widely used at home and abroad every year because of the lifting operation caused a lot of damage to property and casualty accidents. The online detection and orientation of dangerous source is the key to prevention of tower crane safety assessment and accident. Because the metal components long time under alternating loads, the stress concentration area will in the main bearing, member of variable cross section area, the locations of fatigue crack between weld metal and base metal fusion line, has become a major safety accident induced risks. Therefore, the nondestructive detection of the defects has important theoretical significance and engineering value.
Acoustic emission testing technology has the advantages of high efficiency, short cycle, sensitive to the advantages of active defects present in pressure vessel detection, aerospace and other industries have been successfully applied. Due to the crane work site of acoustic emission signal complexity and material sources of acoustic emission parameters characteristics of lack of typical samples, nondestructive acoustic emission technology of tower crane study on detection is still in the exploratory stage. This paper uses the SDAES based on digital acoustic emission detector for tower crane steel prepared by conventional defect test sample, pattern recognition and signal feature parameters of acoustic emission source extraction, the specific contents are as follows:
(1) through data analysis, the common defect forms of steel structure of tower crane are determined. Based on these defects, Q235 base metal, surface crack and welding defect specimen are manufactured.
(2) grasp the use and acoustic emission principle of acoustic emission instrument. Based on the principle of acoustic emission and the principle of acoustic emission, a reasonable experiment plan and analysis method are worked out. Meanwhile, the propagation speed of acoustic emission signal in Q235 material is measured by experimental method.
(3) load test was carried out to collect acoustic emission signals of parent material, surface crack and welding defect specimen under different loads, and real-time monitor the production and change of acoustic emission source.
(4) by acoustic emission signal analysis software on the AE signal acquisition of the positioning characteristics analysis, analysis of the characteristics of AE signal parameters, analysis of frequency spectrum characteristics of acoustic emission signals, and finally summed up the Q235 base metal and with defect distribution range of typical acoustic emission signal of the main characteristic parameters of samples.

【学位授予单位】：东北大学
【学位级别】：硕士
【学位授予年份】：2012
【分类号】：TH213.3;TG115.28

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