Safety Assessment And Experimental Study Of Clamps Structure In Grid

In recent years,the demand for electric energy is rapidly increasing in Chinese society,which requires higher structural safety and operational stability of equipments and components in electric power system.Clamp is an important connection and load bearing component,whose structural safety is directly related to the safe and reliable operation of electric power system.However,during the regular maintenance of power grid,structure crack or fracture problems of the clamp are often found.Regarding those issues,this thesis did mechanical analysis and calculation of two typical kinds of working clamps,and then evaluated the safety of clamp structure based on strength analysis theory of welded structures,safety assessment methods of welded structures and finite element analysis technology.Further more,a fatigue simulation test platform for clamp was designed and developed,on which preliminary test research was carried out next.In general,those works provide firmly support and for acceptance,selection and maintenance of clamp products.More specific works are stated as follows:Aiming at two actual failure issues of the clamp,non-destructive examination methods and fracture surface examination and observation methods were used to inspect inner and surface defects of failure clamps.To analyze and compare the load bearing situation of clamps in different weather environments,mechanical analysis and calculation of two typical kinds of working clamps in 3 typical weather conditions was done based on electrical wire mechanics calculation theory of overhead transmission lines.For clamps with no major defects,static load strength and fatigue strength of clamp were analyzed and calculated,and then static stress-strain analysis,structural reliablity and fatigue analysis in 3 different weather conditions were done using finite element software ANSYS.According to the analysis results,dangerous parts of the clamp structure were confirmed and fatigue life of the clamp structure was predicted.As to clamps with typical planar defects,the safety of clamp structure was assessed based on Structure Integrity Assessment Procedure(SINTAP),and then fatigue crack growth life around the defect was predicted.Those works provide reference and advices for structure safety assessment and fatigue life prediction research of clamp products.A fatigue simulation test platform for clamp was designed and developed,which can ideally simulate the load-bearing state of typical working clamps in power grid.Based on this platform,fatigue crack growth tests were carried out on clamps where different degrees of defects existed.