Effect of inclusion on contact damage evolution of wind turbine gears based on configurational force theory

The gear box of wind turbine is subjected to the complex environment such as random wind load for a long time, and the gear contact fatigue becomes a key factor limiting the stability and reliability of wind turbine equipment. Therefore, the research on the gear contact damage evolution mechanism is faced with difficulties such as complex stress states, damage anisotropy and failure modeling. However, traditional fracture mechanics and damage mechanics are limited in predicting the failure load of complex defects and evaluating the structural integrity. Material configurational force theory can describe the effect of defect configurational change on the free energy of materials and be used to predict the damage and failure behavior of materials. In this paper, a wind turbine gear contact damage model is constructed based on this theory. The gear contact interface stress field simulation analysis is carried out for the key bearing area of gear contact, and the gear contact damage evolution process under contact load is simulated. For the problem of gear failure caused by metal oxide inclusion, the damage evolution model based on J_k parameters is established. The damage evolution process of gear containing inclusions under contact loading is simulated numerically, and the influence of depth, shape and location of inclusions on the damage evolution behavior is analyzed. The research results have shown that the configurational force theory damage model can effectively simulate the contact damage phenomenon of gear and explain the pitting and spalling of gear surfaces. It has theoretical significance to predict contact fatigue life of gear accurately.