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基于小波分析的声发射信号降噪处理方法 总被引:1,自引:0,他引:1
声发射检测过程中的噪声干扰问题,一直是困扰声发射技术工程应用的主要障碍之一,介绍了一种新兴的基于小波分析的声发射信号降噪处理方法,能有效降低噪声。 相似文献
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基于小波的声发射信号参数提取方法 总被引:4,自引:0,他引:4
介绍小波分析方法在声发射信号处理中的应用,提出一套基于声发射信号小波分析的小波基选取的规则方法,并通过实验和仿真证明此方法的有效性. 相似文献
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铁路货车轴承故障声发射信号的小波分析处理 总被引:2,自引:1,他引:2
将声发射技术用于铁路货车轴承故障信号的采集,用小波分析进行带通滤波,从而减少了背景噪声和其他工况的干扰,成功地将正常轴承与故障轴承区分出来。 相似文献
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基于小波分析的声发射源定位技术 总被引:11,自引:0,他引:11
声发射全波形采集技术为基于波形分析的声源定位方法提供了可能。在板状构件中声波的传播模式较为复杂,且不同模式的波到达时间和波速均不相同,从而带来了声源定位误差。将时频幅度分析方法引入声发射源定位技术:从接收到的信号中提取出某一频率的柔性波随时间变化的规律,在理论分析的基础上证明,这个分离信号的最大幅值点所对应的时间就是该频率柔性波群速度的到达时间。根据这个到达时间,以及实际测量出的群速度就可以实现声发射源更精确的定位,试验结果也证明了这种方法的可靠性。 相似文献
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适于声发射信号故障特征提取的小波函数 总被引:2,自引:0,他引:2
小波分析具有很强的弱信号检测能力,适于提取声发射信号的故障特征,但是在目前声发射信号的小波分析中,所普遍采用的小波函数诊断效果欠佳,亟需改进和优化.在分析典型机械故障声发射信号特征的基础上,根据损伤型声发射信号故障特征的提取原理,通过连续小波基函数的构造方法,设计了一种适于声发射信号故障特征提取的小波基函数.将该函数与普遍使用的Daubechies小波同时用于声发射检测的滚动轴承损伤类型及部件的识别,结果表明前者的诊断效果更加清晰、准确、可靠.理论分析和试验研究均证明了所构造小波函数的科学性和有效性. 相似文献
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声发射检测起重机的现状与可行性试验 总被引:1,自引:0,他引:1
起重机是建筑与工业生产中的重要设备,统计表明起重机事故约占我国全部工业企业伤害事故的20%左右。基于此,文中对目前声发射检测在起重机的应用现状进行了综述,将声发射在线监测方法引入到大型门箱式起重机检测的可行性进行了分析,并在线检测。结果表明,声发射应用于大型门箱式起重机的检测是可行的,能有效识别存在的危险的信号;门箱式起重机两端部的圆弧过渡处角焊缝属于应力集中区,是声发射检测时的重点监测部位。 相似文献
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声发射(Acoustic Emission)可以定义为物体或材料内部迅速释放能量而产生瞬态弹性波的一种物理现象,是材料或结构受内力或外力作用产生变形或断裂,以弹性波的形式释放出应变能的结果。在基于虚拟仪器的轮轴故障检测分析平台中,可实现对声发射信号的时域分析、频谱分析、参数分析、小波去噪等主要功能。通过该平台,对具有典型状态的滚动轴承的声发射信号进行了试验研究。试验研究结果表明,对于不同状态的轴承,所测取的声发射信号包络频率特征有着明显的不同,并且和理论特征频率有着一定的关系。 相似文献
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Jiao Jing-pin He Cun-fu Wu Bin Fei Ren-yuan Wang Xiu-yan 《Frontiers of Mechanical Engineering in China》2006,1(3):341-345
For wave propagation in dispersive media, the arrival time of the acoustic emission signal to the sensor is dependent on the
setting of the threshold voltage, which results in the inaccuracy of the acoustic emission location. Based on the wavelet
transform and the theory of modal acoustic emission, a new method is proposed to improve the accuracy of acoustic emission
source location. It is believed that the acoustic emission signal propagation in the structure has the characteristics of
multi-mode and dispersion, and the acoustic emission source location should use the arrival time to sensors obtained from
the output signals not only at the same mode but also at the same frequency. The wavelet transform is used to resolve the
problem. By utilizing the time-frequency data of the wavelet, the frequency-dependent arrival time traveling is easily obtained;
by numerical computation of the wave’s propagation in structure, the group velocity of the guided mode is also obtained, therefore
the accuracy source location is realized. The acoustic emission source location experiments were conducted in a thin steel
plate and results show that the technique is an effective tool for acoustic emission source location.
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Translated from Chinese Journal of Scientific Instrument, 2005, 26(3) (in Chinese) 相似文献
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由于受到油套环空中各种噪声的影响,用声波法测油井动液面过程中,得到的反射声波信号异常复杂,常常出现液面反射位置不容易辨识的情况.该文分析了噪声产生的原因,将小波阈值去噪的方法用于声波法测油井动液面信号的噪声去除.结果显示,利用小波去噪方法处理油井动液面信号能够有效地去除噪声,随着小波分解层数的增加,利用小波方法去噪的效... 相似文献
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Yue SHI Lihong DONG Haidou WANG Guolu LI Shenshui LIU 《Frontiers of Mechanical Engineering》2016,11(3):233-241
Crankshaft is regarded as an important component of engines, and it is an important application of remanufacturing because of its high added value. However, the fatigue failure research of remanufactured crankshaft is still in its primary stage. Thus, monitoring and investigating the fatigue failure of the remanufacturing crankshaft is crucial. In this paper, acoustic emission (AE) technology and machine vision are used to monitor the four-point bending fatigue of 42CrMo, which is the material of crankshaft. The specimens are divided into two categories, namely, pre-existing crack and non-preexisting crack, which simulate the crankshaft and crankshaft blank, respectively. The analysis methods of parameter-based AE techniques, wavelet transform (WT) and SEM analysis are combined to identify the stage of fatigue failure. The stage of fatigue failure is the basis of using AE technology in the field of remanufacturing crankshafts. The experiment results show that the fatigue crack propagation style is a transgranular fracture and the fracture is a brittle fracture. The difference mainly depends on the form of crack initiation. Various AE signals are detected by parameter analysis method. Wavelet threshold denoising and WT are combined to extract the spectral features of AE signals at different fatigue failure stages. 相似文献
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声发射检漏仪在阀门密封性检验中的应用 总被引:3,自引:0,他引:3
提出了利用声发射技术检验电厂阀门密封性的方法,该方法具有准确快速的特点,而且可以确定阀门的内漏程度,为检修工作提供了依据。利用该方法可以减少浪费,缩短检修工期,提高电厂的经济性与安全性。 相似文献
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Jiao Jing-pin Fei Ren-yuan He Cun-fu Wu Bin 《Frontiers of Mechanical Engineering in China》2006,1(2):146-150
It is important to analyze the propagation characteristics of guided waves in acoustic leak location in pipelines. In this
paper, the acoustic leak signal is analyzed in the time-frequency domain. Based on the relation of time-frequency distribution
of the acoustic leak signal and the dispersion curves of guided waves, the mode components of acoustic leak signals were obtained.
The research can provide a guideline for the mode selection in pipeline leak location, and help improve the accuracy of leak
location. 相似文献
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This paper describes measurements of acoustic emission RMS signals obtained from sliding metallic contacts. The results show that RMS measurements are able to differentiate between different wear mechanisms occurring in both dry and lubricated contacts. Further, for the test conditions studied there is a direct empirical relationship between the integrated RMS signal and the wear volume removed from the test ball. 相似文献
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为了快速准确地分析工程表面,提出了一种基于巴特沃思小波的滤波方法。首先,讨论了小波滤波器的低通幅度传输特性,并以此作为选择适合表面形貌分析小波滤波器的依据。然后,介绍了巴特沃思小波滤波器的构造原理,并给出了它的快速实现算法;综合其优良的传输特性和高效的实现算法,以巴特沃思小波作为表面分析的滤波器,对实际表面轮廓进行了多层分解。最后,利用巴特沃思小波建立了表面轮廓评定的基准线,并给出了确定小波分解层数的方法。实验结果表明,巴特沃思小波能够快速准确地实现表面轮廓的多尺度分析,稳定可靠地提取表面中线;在普通计算机上提取11200点数据表面中线仅耗时60ms,利用该中线计算所得R值相对误差仅比利用高斯中线所得R值相对误差大0.12%。 相似文献