Failure mechanism analysis for elastic suspension cable of high-speed railway catenary
With the continuous improvement of high-speed train running speed and the increase of the number of operations,the service environment of high-speed railway catenary elastic suspension cables has become more complex and harsh,which led to their susceptibility to fatigue fracture during service.Based on the service conditions of elastic suspension cables for high-speed railway catenary,combined with failure analysis and dynamic simulation,the failure mechanism of elastic suspension cables was analyzed.Firstly,the fracture mechanism of the sling was systematically analyzed by scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS),which was used to characterize the microstructure and analyze the components of the sling fracture.Then,based on the dynamic theory analysis,the "motor-pantograph-net" aerodynamic model and the pantograph-net rigid-flex coupling multibody dynamics model were constructed respectively.Through the finite element simulation and the fluid-solid coupling method,the coupling between the aerodynamic and multi-body dynamics was realized.Finally,combined with the service conditions of the suspension cable,the effects of the open line,the tunnel and the tension changes in the tunnel on the vibration and force of the elastic sling were simulated.The results show that the lateral indentation of the elastic suspension cable caused by the tightening of the wire clamp,the bending fatigue fracture of the elastic suspension cable resulted in by the fatigue alternating stress caused by the pantograph-catenary vibration,and the atmospheric corrosion environment containing S and Cl ions accelerate the fracture process.The change in aerodynamic lifting force of the pantograph inside the tunnel can lead to a significant increase in the dynamic tension,amplitude,and bending angle of the elastic suspension cable,which is the fundamental cause of premature fatigue failure of the elastic suspension cable inside the tunnel.At the same time,the decrease in tension of the elastic suspension cable further intensifies the fluctuation of the elastic suspension cable,resulting in a further shortened service life of the elastic suspension cable.Therefore,it is suggested to optimize the connection method between elastic suspension cable and clamp to reduce bending stress during connection and improve the service life.
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