Study On The Mechanical And Electrical Behaviors Of Two Kinds Of Cable Structure

Cable structures are widely used in many fields for their good mechanical performance.So,it is the key to studying their mechanical behavior,optimizing their structure and improving their performance for better application.This thesis investigates two kinds of cable structure applications for their mechanical and electrical behaviors:the Rutherford cable used in the high-energy particle accelerator and the flexible cable-type battery in portable electronics.High-field superconducting accelerator magnets are constructed by state-of-the-art Nb₃Sn Rutherford cables for their good properties,such as the highest current densities.In the winding process,mechanical instabilities often occur on the Rutherford cable at the coil extremities.The unwanted deformations of the strands can impact the coil’s overall winding performance,geometrical quality,and electromagnetic performance.Due to the strain sensitivity of Nb₃Sn,the large strain of Rutherford cable during operation will lead to performance degradation and even the quench of the superconducting magnets.Therefore,it is of great significance to study the mechanical behaviors of Rutherford cable in the winding process and in the operation.So,this thesis first studies the mechanical and electrical behaviors of superconducting Rutherford cables under different loads and the mechanical behaviors during the winding process.Firstly,a rapid approach to building the geometry of a Rutherford cable is presented,and the mechanical behaviors of the Rutherford cable under uniaxial tension,transverse compression,bending,and twisting are studied by the finite element method,respectively.In the geometry modeling,the strands’number,strands’twisting angle,clearance between the strands,the cable core,and the twisting chirality are considered.Not only the cable with even number strands but odd number strands,its cable geometry with proper length can be built up easily.Based on the geometry,finite element models are built up to investigate the Rutherford cable’s mechanical behaviors under different loads,such as the uniaxial tension,transverse compression,bending,and twisting.The instability behaviors in tension and Y-direction’s bending are discussed based in the study.The suggestions are given for better mechanical stability of the Rutherford cable.Secondly,the finite element models are built up to study the Rutherford cable winding on a cylindrical surface and a biaxial conical surface,respectively.The coil end’s type,the cable’s winding radius,the strands’twisting angle,and the friction between the cable and the winding surface are considered in the study.The mechanical behaviors of the Rutherford cable during the coiling extremity winding are studied,and the mechanical instabilities of the cable in the coiling process are analyzed.Suggestions are given to improve the mechanical stability of the Rutherford cable when it is wound at the end of the coil.Then,the mechanical and electrical behaviors of the Rutherford cable under different loads at 4.2 K temperature and 19 T magnetic fields are studied.Based on the calibration of the strands,the cable strand’s strain and the critical current are related,and the change of the cable’s critical current is investigated when the cable is under different loads,such as uniaxial tension,transverse compression,bending,and twisting.In the calculation,the strands’twisting angle,the friction between the strands,and the cable core are considered.From the results,some suggestions are given to delay the rapid degradation of the critical current of the cable.Finally,the finite element model of flexible cable batteries under different loads is established,such as uniaxial tension,bending,and twisting.The mechanical and electrical behaviors are investigated,and the influence of the twisting angle of strands and friction in the battery is considered.And the mechanical behaviors’effect on the battery’s resistance is analyzed.The optimizing suggestions in cable-type flexible batteries for complex working conditions are given.