Crack Growth Analysis And Fault Diagnosis Experimental Study Of Helical Gear

Taken the helical gear transmission as study target, discussed thethree-dimensional helical gear tooth root crack propagation path, and also conductedanalysis and experimental research on mesh stiffness changes under condition ofabsence of the tooth root cracks and different crack depths. The main work are listedas follows:(1) Using three-dimensional modeling software, UG, to finish parametricmodeling of secondary helical gears transmission, ABAQUS software and finiteelement theory XFEM was used to simulate three-dimensional crack propagation pathhelical gear tooth root, and verify the helical gear tooth root crack propagation path isdifferent from the spur gear tooth root crack. Crack in helical gear can be divided intotooth width and tooth thickness these two directions, spur gear tooth root crack mostlyends up with surfaces of teeth extend the same direction until fracture occursthroughout the tooth from the tooth root.(2) The simulation software was used to create a ramp vice model toothless crackroot helical gears and Vice models at different crack depth. Using ABAQUSsimulation data post-processing the results of time changing mesh stiffness curve ofhealthy gear model without cracks and varying mesh stiffness curve of the gear toothroot crack model at the different depths. Also study the tooth root crack’s impact onoverall gear meshing stiffness and single tooth stiffness, further more, causes of thiseffect or phenomenon under the different depths discussed at the last.(3)Test gear root cracks using the simple means of wire cutting,designingvibration test platform,dynamic data acquisition tester was used to collect gear cabinetvibration signal of healthy gear without crack and the gear tooth root cracks atdifferent depths. First to do time-domain analysis of gear vibration signals collectedbefore and obtained time-domain correlation features of different crack depth, thenuse spectral analysis method to do spectrum analysis of gear vibration signal collectedbefore and obtained frequency domain characteristics of different crack depths.(4) Introduction to the principles and methods of experimental data processing,according to the relevant method to do data process, first proposed the mathematicalrelation between crack depth and vibration signals spectrum amplitude of gear box, and general mathematical expression between crack depth and vibration signalspectrum in the meshing frequency and its harmonic frequency amplitude of Gear boxwas given, provides a reference method for the follow-up crack study.