Safety Analysis And Local Structural Optimization Of Cross-Track Protective Equipment

With the development of the State Grid and Track Network,the phenomenon of transmission lines crossing tracks is not uncommon,and the construction of crossing tracks is more and more frequent.According to the Track Law of the People’s Republic of China,strict protection measures must be taken for the construction above tracks.Through investigation and research,it found that the traditional protection methods have the problems of long duration,high labor consumption and low safety.In order to solve these problems,one new type of safety protection equipment for crossing the track was developed.Firstly,this paper introduces the basic structure and working process of safety protective equipment for crossing tracks.Through analyzing the working process of protective equipment,it finds out all the dangerous working conditions which are prone to overturning accidents.According to GB/T 3811-2008 Crane Design Code,the overall stability of the protective equipment is analyzed by moment method,and the relationship between the stability safety factor of the protective equipment and the counterweight is obtained.Secondly,referring to the GB/T 33582-2017 General Principles for Finite Element Mechanics Analysis of Mechanical Product Structures,HyperMesh finite element pre-processing software is used to clean up the geometry,simplify the model,select the elements,mesh and adjust the density of each component of protective equipment,and the finite element analysis model of each component is obtained.According to the,GB/T 3811-2008 crane design code,17 kinds of dangerous working conditions are worked out and calculated one by one by using ANSYS software.The calculation results show that the local stress of the main tower exceeds the allowable stress under the erection and torsion conditions,and the structure needs to be strengthened locally.Except for the main tower,the other structures all meet the strength requirements,and the stress of the middle frame of the base is small,so there is a large space for optimizing weight reduction.Thirdly,the buckling stability of the vice-tower structure is calculated,and the influence of the height of the vice-tower on the critical buckling load is analyzed.The results show that the critical buckling load of the vice-tower is 194.14 kN when the height of the vice-tower is normal.With the decrease of the lengthened section of the vice-tower,the critical buckling load of the vice-tower increases gradually.By calculating the tension of the cable and wind rope and analyzing the force of the vice-tower,the maximum vertical compressive load of the vice-tower is determined,and compared with the minimum critical buckling load of the vice-tower,the conclusion that the buckling stability of the vice-tower meets the requirements is drawnFourthly,based on the strength calculation results,the reasons for the excessive stress of the main tower are analyzed,the structure of the main tower is improved,and the strength of the improved main tower is verified.Optimizing the thickness dimension of the intermediate frame of the base by using OptiStruct software,the final optimization scheme can reduce the weight by 533.50 kg on the premise of meeting the strength and stability.Finally,modal analysis of the improved and optimized assembly model is carried out.Using Block-Lanczos algorithm,The first six natural frequencies and mode shapes of protective equipment under the conditions of turning across track and human working are calculated.Combining the meshing frequency of the rotary gear and the walking frequency,the resonance of the structure is evaluated.