Optimal Design And Mechanical Behavior Analysis Of Contact Interface Of Rotating Mechanism In Horizontal Rotating Construction

With the intensive transportation network in China,the number of line crossing projects is increasing.How to reduce the impact of the construction process on the operation of old lines and ensure construction safety is an urgent problem to be solved.The rotating superstructure construction method is widely used because it is safe,fast,and can minimize the impact on the existing lines under the bridge.Among them,the rotating mechanism is the core part of the rotating superstructure construction,and the stress state of its contact surface is related to the success or failure of the swivel process.In the past,most of the researches focused on the control and improvement of the rotating superstructure construction technology,but less on the force and friction analysis of the contact surface.Given this,combined with the theory of contact mechanics,through the finite element numerical simulation method at the macro scale and the molecular dynamics method at the nano-micro scale,this paper deeply studies the force on the contact surface of the rotating mechanism.The main contents are as follows:(1)Finite element analysis of the rotating mechanism.In this paper,the finite element method is used to consider the force situation of the non-slider rotating mechanism and the rotating mechanism with slider in the process of contact,and compared with the contact mechanics theory;on this basis,the influence of eccentric load on the two rotating mechanism is further analyzed.(2)The simplification and stress optimization of the contact interface.Combined with the theory of contact mechanics,a simplified contact mechanics model is proposed,and the spatial distribution of the slider is optimized based on the simplified model.(3)The mechanical behavior of the contact interface in the nano microscale is analyzed.Since the force acting on the spherical hinged contact surface is a complex fluid-structure coupling contact mechanics problem in the lubrication system,to further explore its mechanical mechanism,based on the molecular dynamics method at the nano-micro scale,this paper deeply analyzes the contact theory of the contact surface and the reasons for the periodic fluctuation of the friction force,and further explores the lattice constant,sliding speed,indentation depth,temperature,and viscosity The influence of other factors on friction force.In recent years,the author’s research group has carried out systematic research on the key problems of the contact interface of the bridge rotating superstructure construction.Cai Xiaopeng has established a real swivel model with PTFE slider through the finite element method,and analyzed the stress distribution law of the contact surface of the rotating mechanism in the static and rotating process;Yuan Zhaoxun has aimed at the low accuracy of the friction torque calculation in the existing rotating superstructure construction.Through theoretical derivation and contact mechanics theory,the accurate calculation methods of friction coefficient and horizontal rotation friction moment are proposed,which are verified by finite element analysis and engineering measurement.Different from the above research,the characteristics and innovations of this paper are as follows:(1)considering the influence of eccentric load on the rotating device,the mechanical model of the rotating mechanism is simplified based on the contact mechanics theory,and the spatial distribution of the slider is further optimized based on the simplified model,to reduce the edge stress concentration effect of the contact surface;(2)the stress distribution of the rotating contact surface is analyzed from the nano-micro level.The friction effect of PTFE powder lubrication can provide a theoretical basis for the deep force mechanism of the swivel contact interface under the lubrication of PTFE powder.