With the development of the modern detection technology

carrying out the gear life prediction with initial crack is of great significance to power transmission device in special situations and precision predict the gear life.Based on the theory of linear elastic fracture mechanics

the stress intensity factor at the different pinion crack positions of a five-speed gear-type transmission is analyzed by using boundary element analysis software FRANC3 D.The crack propagation path and process is explored

and the failure characteristics of crack propagation in the central tooth root and its crack propagation life are predicted.This gear crack propagation research methods is not only enriches the theoretical strength of the gear but also provides a good reference for the optimization of gear design theory.