Numerical Simulation Analysis On The Fatigue Crack Propagation Of Rotor Steel 30Cr1Mo1V

Turbine rotor is one of the core components in turbine unit. Under fatigue loading, the rotor may induce crack initiation and crack propagation at long-service conditions. For improving reliability of turbine rotor and developing more accurate life prediction, it is important to know the propagation law of the material when studying on the crack propagation behavior. This discourse takes turbine rotor steel 30Cr1Mo1V as the research target, studying on the crack propagation characteristics through finite element method.The stress intensity factor is key parameter in fracture mechanics, adopted degenerated singular element of 20-node solid186, the variation law of the stress intensity factor K I at the crack tip of rotor steel 30Cr1Mo1V is got when it changes with the crack length and the load level. The result provides a reasonable and effective method for studying on crack propagation law. Also the stress intensity factor of three-point bending specimen with different crack length is calculated by the same way.Stress-strain distribution and the variation of the crack propagation path are got by analyzing I-II mixed-mode crack of three-point bending specimen with different offset distance through FRANC2D software, the crack deflection angle is calculated by getting the value of K I and K II at crack tip. The general trends are that firstly the crack is inclined to the far supporting point then to the midline, with crack propagation, the crack propagation behavior is changed from I mode into I-II mixed-mode. The influencing factors about crack propagation rate are analyzed, and based on the finite element simulation of the crack propagation path, the curve of the fatigue crack propagation rate and cycle number changing with the crack length are draw by Paris formula, the results showed that :as the offset distance increases, crack propagation rate get slow and loading cycles increase when the crack length get to the same level and it mean the longer fatigue life, the propagation don't occur when the offset distance reached a certain value, at last domestic with Westinghouse calculation results were compared and calculated.