Crack propagation law of low speed and heavy load gears

The research content of gear crack and the research status of gear stress intensity factor at home and abroad are introduced in detail, and the mature and less researched problems up to now are summarized. On this basis, the research object and content are determined.

Firstly, the parametric modeling of low-speed and heavy-duty gear is carried out by using SolidWorks, and the accurate modeling of gear is the basis of analysis. Secondly, the dynamic contact analysis of gear meshing is carried out by using ANSYS Workbench, and the maximum stress area, that is, the “most dangerous” area, is obtained, which is defined as the fatigue crack initiation area, paving the way for further analysis.

The finite element method for the analysis of gear dynamic characteristics is summarized. The influence law of the crack at the base circle and the root of the tooth on the natural characteristics of the gear under different lengths is analyzed by using ANSYS software. The dangerous frequency of the cracked gear is determined, which provides a theoretical basis for the design of gear transmission mechanism.

The variation of stress intensity factor (SIF) of tooth root crack is studied. A three-dimensional finite element model with initial semi elliptical crack is established by using ABAQUS software. The SIF of semi elliptical crack leading edge is calculated, and the influence of crack size, crack shape and load variation on SIF of tooth root crack leading edge is analyzed.

The simulation principle of crack propagation based on extended finite element method is introduced. Then the crack propagation of low-speed and heavy-duty gear with crack is analyzed by ABAQUS, and the crack propagation law under different initial crack positions is studied.