Contact Analysis Of Fretting Wear And Fretting Fatigue Research Of Transmission Lines

High voltage overhead transmission line in operation,especially in the flat area,low wind speed prone to high-frequency micro amplitude vibration of the breeze,so that the conductor is in the vibration.Over time,there will be fatigue broken stocks,or even off the line,threatening the safe operation of overhead transmission lines.The fretting damage and fretting fatigue are the most common failure modes.Therefore,it is of great significance to study the mechanism of fretting damage and fretting fatigue of overhead transmission lines.The fretting fatigue tests of fretting wear characteristics of conductor can be observed,but the test cost of the material and financial resources and time costs are higher.So the finite element method of micro wire wear fine modeling is applied in this paper,in order to reduce and gradually replace the prototype test.In this paper,the contact stress between the strands of steel cored aluminum strand during the breeze vibration is studied.In this paper,LGJ120/7 steel cored aluminum strand is taken as the research object,and the spatial structure of the conductor is modeled by finite element method.Through the static analysis of the model,the profiles in different tension under each layer between the contact stresss is givern,concluding that the stress level of the outermost aluminum wire is higher;by applying the displacement load on the model,this paper analyzes the distribution and law of force and displacement of a contact point in different Fretting Amplitude and the vibration frequency.By comparing with the results of the empirical formula the calculation error is small,which is consistent with the wear mechanism of wire.In this paper,the fretting fatigue mechanism of transmission line is analyzed by finite element method.In this paper,the finite element model of fretting fatigue is established by taking 1/4 of the vertical aluminium stranded wire contact with each other.The validity of the model is verified by comparing the calculated results of the stress and the contact area with the theory of three-dimensional Hertzian contact.The influence of the contact load on the stress distribution and the stress level of the contact zone is analyzed by the finite element model.The effect of tensile force on the stress distribution in the contact zone is analyzed by the finite element method.The results show that the appropriate increase of the wire tension can weaken the stress of the contact area and relieve the stress fatigue.In this paper,based on the theory of linear elastic fracture mechanics,accordnig to the data in reference,and the dimensionless strain fitting formula of stress intensity factors,the range of stress intensity factor is determined.This paper gives the fretting fatigue life prediction method,and compares with experimental results in the literature,showing the effectiveness of the method.