希尔伯特-黄变换方法的构件残余应力检测方法的试验研究

发布时间：2018-01-16 21:21

本文关键词：希尔伯特-黄变换方法的构件残余应力检测方法的试验研究　出处：《长春工业大学》2017年硕士论文　论文类型：学位论文

【摘要】：随着现代科学水平的日益更新与迅速发展,人们对于构件的结构稳定性、疲劳强度以及使用寿命等有了更加严格的要求。铸造、锻压、焊接、切削等机械加工工艺都会使构件产生不同程度的残余应力,残余应力的存在严重影响到构件的使用性能。因此,无损、快捷、准确、可行的构件残余应力检测方法已经成为国内外学者研究的热点。根据当前已经公开的资料得知,还没有将希尔伯特-黄变换方法运用到构件残余应力检测的领域。本文采用希尔伯特-黄变换方法对构件的残余应力的检测进行了研究,得到构件残余应力存在与否的判断准则。首先,对该课题的背景、研究现状以及希尔伯特-黄变换的基本理论做了详细介绍,针对经验模态分解方法出现的模态混叠现象,采用总体平均经验模态分解方法,结果表明,此方法更加准确有效。然后分别对单自由度系统振动特性和多自由系统振动特性及其各自总体平均经验模态分解方法进行了分析研究,得到机械系统固有振动模式函数与固有模态函数的高度对应关系。其次,利用丹麦BK信号采集系统分别采集未经处理的焊接钢板、第一次热时效处理后的焊接钢板以及第二次热时效处理后的焊接钢板的振动信号,并采用经典的钻孔法对未经处理的焊接钢板、第一次热时效处理后的焊接钢板以及第二次热时效处理后的焊接钢板进行焊接残余应力检测,得出不同状态下焊接钢板的残余应力分布特点。最后,采用希尔伯特-黄变换对采集到的焊接钢板振动信号进行分析处理,得到其各自的希尔伯特谱,为了比较不同振动信号希尔伯特谱的差异,本文提出了判断指标:时间幅频积。针对不同状态下的振动信号希尔伯特谱,求出各自时间幅频积,然后分析时间幅频积的变化。结果表明:采用希尔伯特-黄变换方法,通过对希尔伯特谱时间幅频积的研究能够准确判断焊接钢板是否存在残余应力,并利用钻孔法的检测结果来验证此方法,两者保持一致性,显示出该方法在构件残余应力检测方面的可行性。
[Abstract]:With the rapid development of modern science, there are more stringent requirements for structural stability, fatigue strength and service life of members. Casting, forging, welding. Cutting and other machining processes can make members produce different degrees of residual stress, the existence of residual stress seriously affects the performance of the components. Therefore, non-destructive, fast and accurate. The feasible method of residual stress detection has become a hot topic for domestic and foreign scholars. The Hilbert-Huang transform method has not been applied to the field of component residual stress detection. In this paper, the Hilbert-Huang transform method is used to study the residual stress detection. First of all, the background, research status and the basic theory of Hilbert-Huang transform are introduced in detail. Aiming at the phenomenon of modal aliasing in the empirical mode decomposition method, the method of total average empirical mode decomposition is used, and the results show that. This method is more accurate and effective. Then, the vibration characteristics of single degree of freedom system and the vibration characteristics of multi-free system and their respective average empirical mode decomposition methods are analyzed and studied respectively. The relationship between the inherent vibration mode function and the inherent mode function of mechanical system is obtained. Secondly, the unprocessed welded steel plate is collected by the Danish BK signal acquisition system. The vibration signals of the welded steel plate after the first heat aging and the welding steel plate after the second heat aging treatment were analyzed. The classical drilling method was used to weld the untreated steel plate. The welding residual stress of the welded steel plate after the first heat aging treatment and the welding steel plate after the second heat aging treatment were detected, and the distribution characteristics of the residual stress of the welded steel plate under different states were obtained. The Hilbert-Huang transform is used to analyze and process the vibration signals of welded steel plates, and their Hilbert spectra are obtained. In order to compare the difference of Hilbert spectra with different vibration signals. In this paper, the judging index, time amplitude-frequency product, is proposed. According to the Hilbert spectrum of vibration signal in different states, the time amplitude-frequency product is calculated. The results show that the Hilbert-Huang transform method can accurately judge whether the residual stress exists in welded steel plate through the study of Hilbert spectrum time amplitude frequency product. The results of borehole method are used to verify this method, which shows the feasibility of the method in detecting residual stress of components.
【学位授予单位】：长春工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TG404

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