Dynamics analysis for an improved gear model considering velocity-dependent mesh stiffness with tooth root crack

Dynamic modeling of gear systems is typically constrained by the assumption of small vibration displacements. Additionally, the nonlinear effect of driving speed on evaluating the mesh stiffness with tooth root crack is neglected by many scholars. Based on this, a novel nonlinear dynamic model of a spur gear system that accurately accounts for large vibration displacements is established in this paper. Meanwhile, an original computational algorithm(OCA), based on analytical-FEM framework, is proposed to calculate the velocity-dependent time-varying mesh stiffness(V-TVMS) with tooth root crack, and whose accuracy is validated by FEM. The proposed dynamic model is compared with the traditional model under different support stiffness to illustrate its adaptability to large vibration displacements, and the influence of V-TVMS under different crack depths on the dynamic characteristics of the gear system is analyzed. The results analysis indicates that the fluctuation of V-TVMS intensifies with the increase of crack depth, which further exacerbates the nonlinear vibration of the gear system. And these phenomenons become more pronounced as crack depth increases. The reslut will provide valuable references for future studies on dynamics of cracked gears. © 2024 Elsevier Ltd