Temperature Field Analysis And Damage Characterization Of High Speed Sliding Electrical Contact

High speed sliding electrical contact belongs to the transient electric contact which changes over time and the contact state of each moment is different.Dynamic electric contact is widely used in electrified railway system,aerospace and other research fields.The dynamic electric contact whose elements and interface with large electric current belongs to high current-carrying friction and wear issue under special conditions.Because of the existence of large current and sliding friction,a lot of thermal will be generated on the contact interface of the contact elements and lead to the temperature increment.The temperature rise not only result in element soften even deformation,makes the element in a state that the damage is more easy to form,but also strongly changes the contact state and causes serious accidents.Therefore,more and more scholars began to study the effective and reasonable method to reduce the temperature rise of the contact surface and the method of restraining the damage formation.In this paper,the real-time measurement and simulation analysis were studied about the surface temperature under different experimental conditions of high speed sliding electrical contact.Based on the theory of heat transfer and finite element theory,a two-dimensional finite element model of electrical contact friction pair was established.The temperature rise of the contact pairs under the condition of pure mechanical friction heat,mechanical friction heat and contact resistance coupling heat is simulated.In the simulation,the method by controlling the single variable was adopted to study the rule of the coupling temperature changing under different electric current,relative sliding speed,displacement of the slider,the friction coefficient of the contact surface and the normal contact pressure.In order to verify the reliability of the simulation model and the correctness of simulation rules,non-contact infrared thermometer was used to measure the real-time temperature of the contact surface in high speed sliding electric contact experiment under different experimental conditions and the temperature changing principles with various experiment parameters was established,the experimental results are consistent basically with the results of theoretical analysis,which showed theeffectiveness of the simulation model.After many experiments,the surface morphology of the fixed contact element rail and the moving element slider was collected,the damage volume of the rail surface before and after the experiment are calculated and compared and the cause of damage formation is analyzed.The influence of different experimental conditions on the damage of the slider surface was obtained by more experiments.In this paper,the research results about the coupled temperature of high speed current-carrying contact surface provide a reference for how to reduce the temperature of the contact surface,select the appropriate surface contact material and restrain the formation of damage.