Study On Wireless Condition Monitoring System Based On Acoustic Emission Technology

As an effective non-destructive testing method,acoustic emission detection technology has been widely used in fault diagnosis and condition monitoring of mechanical equipment.The development of acoustic emission technology in monitoring the structure and mechanical components is significant to ensure the safe operation and production of mechanical equipment.The wired communication methods are not able to meet the actual needs since the objects to be tested usually have complicated structure.This study proposed a wireless monitoring system based on acoustic emission technology,and analyzed the tensile damage process of metal materials with different initial condition.The main contents are as follows:(1)The applications of acoustic emission technology and wireless sensing technology in the field of mechanical equipment fault diagnosis and condition monitoring,especially gears and bearings,are introduced.The development and current situation of acoustic emission detection technology and wireless communication technology in domestic and foreign are explained at the same time.(2)A set of wireless communication system based on amplitude modulation for acoustic emission signals is designed by the means of circuit design and simulation,mainly focusing on the amplitude modulation circuit,peak envelope detection circuit and band-pass filter circuit.The feasibility of the system was tested in the experiment.(3)An self-built online monitoring system for acoustic emission signals based on the LabVIEW platform was designed.A signal truncation method named amplitudeenergy double threshold was proposed,which effectively reduced the number of data.At the same time,the parameter analysis,waveform analysis and data storage of acoustic emission signals are completed in the software system,and the application of wavelet analysis in noise reduction of acoustic emission signals is introduced.(4)Tensile experiments were carried out on three prototypes with different initial condition.The proposed software system was utilized to monitor the tensile process of the prototypes.By comparing the feature values of the acoustic emission signals of the three test pieces at different material stretching stages,the damage state of the prototype and the tensile state can be qualitatively determined.