Design And Research On Prestressing Primary Tensioning Machine Of Steel Bar

In modern society,concrete is almost everywhere.In order to improve the service life of concrete structure,how to improve the structural strength of concrete becomes an important issue.Prestressed concrete in concrete is often applied to places subject to large loads because of its special characteristics.Prestressed concrete structures are mainly provided with prestressed reinforcement in the concrete structure to provide a pre-tightening force on the concrete structure.However,the size of the prestressing and the loading process need to be strictly controlled because these two factors will directly affect the production of Strength of concrete equipment.The loading accuracy of initial stress of rebar has a great influence on the stability and accuracy of subsequent loading.Therefore,there is a need for a prestressing steel bar pretension device to precisely control the magnitude of the initial stress.Therefore,in this paper,we design a kind of steel pretensioning equipment to meet the production needs.In this article,we will focus on the following:(1)By consulting the literature,understand the characteristics of prestressed concrete and preparation methods,and need to know which of the prestressed concrete,will directly affect the quality of production.At the same time,the current situation of prestressed steel bar loading equipment research situation,to understand their advantages and disadvantages,and on this basis proposed a new type of prestressed initial tensioning equipment.(2)The mechanical structure of prestressing prestressing equipment is designed to meet the company's requirements.At the same time,the designed mechanical structure needs the analysis of the finite element structure to determine its strength.Proposed improvement of the mechanical structure and processing the main attention of the equipment.(3)According to the system design of hydraulic system,including the design of the hydraulic cylinder,hydraulic valve selections,hydraulic pump and motor selection.At the same time,according to the force output of the actuator,the speed change during the loading of the hydraulic cylinder is analyzed to facilitate the calculation of the required flow rate in the system.(4)According to the hydraulic cylinder parameters and the selection of the hydraulic valve,the main circuit of the valve-controlled hydraulic cylinder that is stretched hydraulic cylinder modeling.After the establishment of the model,the simulation of its open-loop response using MATLAB was used to verify with the model established by AMESim later.(5)The AMESim software was used to establish the model of the proportional three-way pressure reducing valve and analyze the characteristics of the proportional hydraulic valve.At the same time,the model of proportional pressure reducing valve controlled hydraulic cylinder was established,the operation of hydraulic cylinder in the model and the output pull force were analyzed,and compared with the open loop model established by MATLAB.(6)Using the model developed by AMESim software to simulate with MATLAB.The AMESim model is converted to S function,input to MATLAB,in order to achieve closed-loop control.At the same time adding PID control system to improve the dynamic characteristics of the system.Finally,the fuzzy PID control is introduced into the system,and the robustness of the system is improved by changing the PID parameters within a certain range.