Fatigue Life Reliability Design Of TBM Cutterhead

With the continuous expansion of the development scale of underground engineering such as tunnel construction,the research on reliability is paid more and more attention by engineering designers.The full-face tunnel boring machine(TBM)has become the first choice of tunneling machinery and equipment in engineering because of its high efficiency,economy and safety.Cutter is the core component of TBM,which directly interacts with rock.In the process of tunneling,the working condition is complex and the environment is harsh,and the cutter frequently breaks and fails,which seriously affects the service life of TBM.In order to ensure the safety and reliability of TBM cutterhead in use,it is necessary to design its reasonable reliability.Based on this,this paper takes TBM cutterhead as the research object to study its fatigue life reliability design.The main contents are as follows:(1)The structure and functional characteristics of TBM cutter head were analyzed and failure data were collected;The simulation model of cutter head was established,and the statics and dynamics simulation analysis were carried out respectively according to the loading conditions of various operating conditions,and the strength was checked.At the same time,the basic units under various working conditions are analyzed,and the overall structure of TBM cutterhead is determined according to its structural function and actual failure area,and the cutterhead is divided into system-subsystem-basic unit structure.(2)According to the failure form of TBM cutterhead and the theory of fatigue crack growth,the crack growth rate model of cutterhead is established.Based on linear fracture mechanics and fatigue cumulative damage theory,the reliability calculation model of the crack length of cutter head is established.Based on the fatigue cumulative damage of crack propagation,the limit state equation is established,and the method of solving the basic unit reliability of TBM cutterhead is established on the basis of Monte Carlo.(3)A multi-factor reliability allocation method considering complexity,maintainability,failure frequency,severity and harmfulness is proposed,and the specific allocation process is described.In addition,various factors are analyzed,and the weight solution theory of each influencing factor is introduced,which provides the basis for the reliability design of TBM cutterhead.(4)Based on the division of cutterhead system structure and multi-factor reliability allocation method,the reliability allocation of TBM cutterhead from system to subsystem to basic unit is completed,Compared with the calculated reliability results,the feasibility of the allocation method is verified.According to the allocation results,the failure criterion and design standard of TBM cutterhead are established,and the reliability design is completed.(5)Based on the GUI graphical user interface of MATLAB,the multi-factor reliability allocation software of TBM cutterhead is compiled.The main function of the software is to realize the efficient and rapid calculation of allocation results of TBM cutterhead system-subsystem and subsystem-basic unit.