共查询到16条相似文献,搜索用时 156 毫秒
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
摘 要:针对移动滚动轴承非接触声发射检测中,一个故障源信号可能被多个传感器采集,致使这些声信号包含故障信息不完整且存在重叠的问题,综合考虑声波传播理论、多传感器声信号时差关系、滚动轴承典型故障撞击频率等,建立滚动轴承故障非接触多传感器声信号融合方法。建立滚动轴承故障非接触多传感器声发射检测试验台,分别采集移动滚动轴承滚动体、外圈和内圈故障声信号。采用融合方法对同声源信号进行处理,利用信号相似理论证明了融合信号与故障源信号的相似程度高于各传感器声信号。采用声发射累计撞击计数法对融合处理后的滚动轴承不同故障声信号进行分析。结果表明,该融合算法能有效地处理多传感器接收的同声源信号,可利用融合后信号进行准确的故障识别。 相似文献
11.
12.
T. Morita K. Aoki K. Satoh T. Fujimori M. Tanabe 《Microgravity science and technology》2003,14(2):29-32
Combustion of an isolated fuel droplet in acoustic fields is investigated by microgravity experiments. The influence of standing
sound wave is examined by varying amplitude of velocity fluctuation, frequency of sound and location of droplet. Variation
of flame shape and burning rate is determined. As a result, spreading flame to one direction as well as normal gravity is
observed as amplitude of velocity fluctuation increases. On the other hand, hemispheric and conical flames are observed when
the amplitude of velocity fluctuation is small. Direction of flame spread is changed depending on relative location between
velocity anti-node and the droplet. The cause is considered as acoustic radiation force in standing sound wave. Burning rate
is significantly enhanced by velocity fluctuation and the amount of the enhancement is changed by sound frequency or relative
location. 相似文献
13.
长基线水声导航定位方法利用各信标到水下航行器的信号传播时间和等效声速来估计水下航行器的位置,但各信标到水下航行器的等效声速估计存在误差,导致定位误差较大,且随着导航距离的增加,定位误差呈增长趋势。针对这一问题,提出了一种基于粒子滤波的水声导航定位方法,将等效声速和水下航行器的位置作为估计状态参量,通过测量信标信号到水下航行器的传播时间,建立粒子滤波模型对其位置进行估计,准确地估计并跟踪等效声速变化,从而提高定位精度,减小估计误差。仿真结果表明,在水下航行器初始位置未知的情况下,与常规方法相比,文中所提方法的定位精度提高了4倍左右。 相似文献
14.
无砟轨道是典型的层状混凝土结构,脱层缺陷是其最常见的损伤形式,影响着高速列车的安全运行。传统的合成孔径聚焦成像方法是基于恒定声速的超声检测方法,忽略层间的声阻抗差异以及声波在层间界面处的折射,导致声束难以在缺陷处聚焦,声波在层状结构中传播的时间误差较大。鉴于此,提出了一种多层结构合成孔径聚焦成像方法,充分考虑多层结构中的层间声速差异,采用射线追踪方法准确获取声波在多层结构中的传播时间。在此基础上,分析了不同入射波模式以及不同激发频率对多层结构合成孔径聚焦成像结果的影响。结果表明:采用多层结构合成孔径聚焦成像方法,使用频率为50 kHz的横波入射成像分辨率更高,对无砟轨道脱层缺陷检测效果更好。该研究为该类缺陷检测提供了理论支撑。 相似文献
15.
The acoustic emission (AE)-based technique is considered to be a promising way to real-time monitoring of microstructural changes and damage evolution in Ceramic Matrix Composites (CMCs). The present paper proposes a testing protocol that combines acousto-ultrasonics (AU) and acoustic emission (AE) monitoring, with a view to obtain both global and local definite characteristics on damage modes and kinetics. It is developed and assessed on SiC/SiC minicomposites, which are appropriate test specimens to establish sound relations between mechanical behavior and damage modes. AU wave velocity measurements provide a global measure of matrix cracking damage and the relations between crack growth and damage characteristics. AE monitoring allows accurate localization of AE sources taking into account wave velocity dependence to damage as well as differentiation of the damage modes, which control the mechanical behavior. Finally, multivariate analysis of AE data allowed classification of signals into clusters, which were successfully associated to the various damage modes. 相似文献
16.
Shizeng Lu Qingmei Sui Huijun Dong Yaozhang Sai Lei Jia 《Journal of Modern Optics》2013,60(8):742-749
Acoustic emission location is important for finding the structural crack and ensuring the structural safety. In this paper, an acoustic emission location method by using fiber Bragg grating (FBG) sensors and particle swarm optimization (PSO) algorithm were investigated. Four FBG sensors were used to form a sensing network to detect the acoustic emission signals. According to the signals, the quadrilateral array location equations were established. By analyzing the acoustic emission signal propagation characteristics, the solution of location equations was converted to an optimization problem. Thus, acoustic emission location can be achieved by using an improved PSO algorithm, which was realized by using the information fusion of multiple standards PSO, to solve the optimization problem. Finally, acoustic emission location system was established and verified on an aluminum alloy plate. The experimental results showed that the average location error was 0.010 m. This paper provided a reliable method for aluminum alloy structural acoustic emission location. 相似文献