Finite element analysis and fatigue life prediction of tunnel boring machine cutter head

The cutter head, a pivotal component of the tunnel boring machine (TBM), endures high-risk working conditions involving high temperature, pressure, and hardness. The intricacy and variability of working conditions give rise to high torque, substantial thrust, and stochastic impact loads, ultimately leading to the damage and failure of the cutter head. In this paper, the mechanical and fatigue properties of the 8 -meter-class spoke-web composite cutter head have been investigated through the finite element method (FEM) more academically. Specifically, this article explores the typical working conditions (full load, eccentric load, and extreme condition) and different geologies (soft soil, composite formation, and hard rock) that the cutter head encounters. The findings demonstrate that under extreme working conditions, the cutter head experiences a maximum equivalent stress of 250.76 MPa. Additionally, the maximum displacement of 4.83 mm occurs on the outer ring when subjected to a one-half eccentric load. Concisely, the FEA validates the cutter head’s structural rationality in stiffness and strength. Furthermore, a fatigue durability analysis of the cutter head structure was conducted using nCode DesignLife based on the stress method, determining its fatigue life range to be between 6.857E+4 and 1.253E+7 cycles, with an error not exceeding 20% compared to the theoretical fatigue life. This research provides valuable insights for the structural design and fatigue life studies of cutter heads for TBMs.