基于声发射的机械断裂定位研究

发布时间：2018-01-04 21:32

本文关键词：基于声发射的机械断裂定位研究　出处：《中国矿业大学》2015年硕士论文　论文类型：学位论文

【摘要】：随着声发射技术的发展和相关学者对金属材料声发射现象的研究,以及信号处理技术的提高,使得声发射在机械故障检测领域有了更广阔的应用。目前的声发射检测设备多以PC机为平台,通过软件提取声发射信号的特征参数,对于密集型声源经常漏失信号,且针对机械断裂故障的声发射源定位研究不足。基于此,本文设计了基于嵌入式平台的声发射检测仪,研究分析了特征参数提取和源定位。本文首先讲述了机械铸件释放声发射波的机理,介绍了声发射信号的时域特征、频域特征和常用特征参数的含义及计算公式;介绍了最常用的基于时差的线性定位、平面定位和三维定位原理;根据声发射检测系统各环节容易引入噪声的特点,设计了针对于机械铸件的模拟带通滤波器;设计了声发射信号识别状态机,利用FPGA的硬件平台优势,高效完成特征参数的提取;针对声发射源时差定位提出基于离群点分析的Chan定位算法,该算法原理简单、计算量小且定位精度高;最后通过方案论证完成对元器件的选型和选定基于FPGA和STM32的硬件平台,并着重讲解了特征参数提取的Verilog HDL代码和定位算法的C代码实现思路。为验证模拟滤波器的去噪效果、特征参数提取效率和声发射源定位精度,通过Modelsim时序仿真和与实际仪器数据比较,证明系统可以完成4通道数据采集、实时特征参数提取并完成声发射源定位。本文研究成果对后续针对机械故障的声发射检测和专用仪器设备研制具有实践意义。
[Abstract]:With the development of acoustic emission technology and related research on the emission of metal material sound, and signal processing technology, the acoustic emission in the field of mechanical fault detection has a wider application. At present, the acoustic emission testing equipment based on PC platform, through the software to extract characteristic parameters of acoustic emission signals, for intensive sound source often missed signal, and according to the mechanical fault acoustic emission source location research. Based on this, this paper designs an embedded platform of acoustic emission tester based on research and analysis of the extraction and localization parameters. This paper describes the mechanism of mechanical casting release of acoustic emission wave, the time domain features the acoustic emission signal, the meaning and calculation formula of the frequency characteristics and the common characteristic parameters; introduces the linear positioning time based on the most commonly used, plane positioning and three-dimensional positioning according to the principle; The characteristics of acoustic emission of each link detection system to introduce noise, designed for simulation of mechanical casting band-pass filter design; acoustic emission signal recognition of state machine, using the advantages of FPGA hardware platform, extraction and efficient completion of characteristic parameters; the acoustic emission source location is proposed Chan localization algorithm based on the outlier analysis. The algorithm is simple in principle, less computation and high accuracy; finally through the demonstration program completed selection of components and selected based on FPGA and STM32 hardware platform, and explains the Verilog HDL code and localization algorithm feature extraction C code method. Filter denoising effect for simulation, feature extraction efficiency acoustic emission source location accuracy by comparing Modelsim simulation and actual data and instrument, it is proved that the system can complete 4 channel data acquisition, real-time characteristic parameters The localization of acoustic emission sources is extracted and completed. The results of this paper have practical significance for the follow-up of acoustic emission detection for mechanical faults and the development of special instrument and equipment.

【学位授予单位】：中国矿业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TG115

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