| China’s energy has entered a new stage of high-quality development.Renewable energy,such as wind power and photovoltaic,has gradually become the main energy source instead of supplementary energy,directly leading to the increasingly prominent problem of power grid stability.On the other hand,with the peak of carbon and the window period of carbon neutrality,reducing carbon emissions has become an urgent problem to be solved.As a typical form of physical energy storage,flywheel energy storage can not only improve the flexibility of power grid,but also greatly reduce the consumption of chemical batteries,which is of great significance to promote the reform of China’s energy system.This article is an object with high-power energy storage flywheel rotor overloading steel needle,through theoretical analysis and finite element simulation and analytic calculation methods,the ideal state of rotor and defects of the rotor made life and fatigue fracture analysis,for insight into the energy storage system stress and fatigue fracture characteristics of the rotor at run time,reasonable extension of the flywheel service life and provide technical support for safe and reliable operation,paper main research work is as follows:(1)The stress characteristics of the flywheel rotor under high speed rotation were studied,and the stress distribution and variation rules of the flywheel during charging and discharging were discussed.The stress results of finite element analysis were compared with the analytical results to verify the results.The analysis results show that the maximum stress of flywheel in operation occurs at the junction of flywheel journal,and it is necessary to eliminate the stress concentration at the position of flywheel journal when the flywheel is delivered.(2)Taking the flywheel rotor in ideal state as the object,the load spectrum was constructed according to the set working conditions,the fatigue life of the flywheel under full load condition was calculated,and the standardized model of stress intensity factor of the flywheel rotor was deduced and calculated,which provided a reference for the fatigue life calculation and fatigue fracture analysis of rotor structural parts.(3)A virtual crack model was established at five key points on the rotor.The fatigue crack initiation,residual strength and fatigue crack propagation of flywheel were analyzed by Paris formula and crack hysteresis effect.The results show that the circumferential stress at the crack has a great influence on the rotor FCG(fatigue crack propagation)life.The FCG life of the rotor is much smaller than that of other positions after the crack occurs at the journal joint and the rotor core.Moreover,the crack tip can be deactivated and the service life of the rotor can be prolonged by adding an appropriate amount of single peak overload during the operation of the flywheel. |
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