Research On The Methods Of Monitoring And Detecting The Multi-physical Fields Of Tooth Surface Contact Fatigue Damage

Gear transmission is a widely used transmission method.Surface contact fatigue failure is one of the main failure modes of closed gears,so the status monitoring of gear transmission system is very important.Firstly,this paper introduces the significance of gear contact fatigue damage monitoring and the research status and development of various detection technologies.Then,based on DU gear contact fatigue test-rig,several sets of tests are designed.The digital signal processing technology is applied to the collected vibration signals and acoustic emission signals.and the information contained in oil debris and solid contaminants are studied.After the analysis of the experimental data,this paper reached the following conclusions:(1)Part of the gearbox vibration acceleration signal dimension time-domain parameters(root mean square value,the magnitude of the square root,absolute mean,kurtosis,variance)can be exponential or quadratic polynomial mathematical model constructed with load.The change of these parameters' value can be used as a reference to the fault diagnosis of the gearbox,but they are not sensitive to the change of gear surface contact fatigue damage.The dimensionless time-domain index such as waveform index,margin index and kurtosis index can reflect the severity of tooth surface damage to some extent.(2)The time-domain dimension parameters of the acoustic emission signal of the gearbox such as root mean square voltage,average signal level,variance,kurtosis,energy and the dimensionless characteristic parameter such as peak value index,kurtosis index,both are effective parameters to monitor gear fatigue damage.The parameters of energy,root mean square frequency,spectral center of the AE signal can reflect the difference of different gear materials.These frequency-domain parameters vary obviously with load and the rotational speed,which can be used as detecting parameters for the gear surface contact fatigue.(3)Different wear mechanism produce different debris in the gear contact fatigue test.The sort of the debris,the concentration and size distribution of the solid particles can reflect the degree of gear contact fatigue damage.The difference of solid particle contamination in the oil of the gear fatigue test rig under the same load and speed can reflect the difference of the anti-fatigue performance of the gear materials of the two gear box.Finally,it is shown that vibration signal detection,acoustic emission signal monitoring and oil debris detection both have a certain effect on the monitoring of gear contact fatigue damage.In the future,a comprehensive testing platform should be established.The detection and monitoring of gear contact fatigue damage will be more accurate with the use of data mining technology and information fusion technology.