Abstract: Meshing characteristics of spur gear pair were researched using finite element method. Parametric finite element model of modified spur gear pair was built on the on the basis of APDL. Numerical simulation of gear meshing was performed via application of explicit dynamic software LSDYNA. Dynamic meshing characteristics caused by gear meshing such as dynamic contact force and dynamic transmission error(DTE)were obtained， and the effect of modification coefficient on dynamic meshing characteristics was studied. Static transmission error(STE)was compared with the aforementioned DTE. Finally the reasons for the difference between the DTE and STE were discussed. The results shown that under different modification coefficients， the meshing frequency is always the main frequency component. Other frequency components are affected by modification coefficient， and amplitude of the frequency component close to natural frequency is relatively larger. The STE is much different from the DTE on both time and frequency domains.

Key words: modification coefficient, spur gear, transmission error, meshing characteristics, ANSYS/LSDYNA