Research On Straightening Model Of T-type Guide Rail For Remanufacturing

With the rapid development of economy,a large number of mechanical and electrical products are scrapped.If they are not properly handled,they will cause a series of environmental and social problems,such as environmental pollution and resource waste.Remanufacturing technology is an effective way to solve the problem of scrapped electrical products and reuse.T-type guide rail of elevators is a typical part that can be remanufactured and reused.However,the main reason affecting the remanufacturing efficiency and product quality is the high dependence of manual experience in the process of measurement and straightening.In this paper,T-type guide rail is taken as the research object,and the straightening model for remanufacturing process is established to meet the real-time and high-precision requirements.At the same time,a straightening theoretical model considering the initial residual stress is established,and an accurate straightening model is proposed by using the least square support vector machine.Firstly,based on the analysis of the standard and evaluation method of the straightness measurement of T-type guide rail,the overall scheme of the straightness measurement was proposed.Based on the theory of elastic-plastic mechanics and the basic principle of threepoint bending straightening,the curvature analytical model of T-type guide rail lateral bending and top surface straightening was derived.Secondly,in order to control the overall bending of the guide rail,the reverse bending straightening model based on the finite difference method was established.Taking the straightening stroke as the iterative variable and the minimum straightness error as the objective function,the gradient descent method was used to iteratively optimize the straightening stroke,and the Matlab program was written to achieve the above process.The Python parametric modeling function,straightness error calculation function and parameter optimization function were written through the script interface of ABAQUS secondary development based on simulated annealing algorithm to realize the parameter optimization process of straightening stroke.By modifying the finite difference model with finite element data,a straightening model based on the finite difference correction was proposed,and the feasibility of the straightening model was verified by experiments.Then,in order to study the influence of the initial stress condition of the guide rail on the remanufacturing process,a straightening theoretical model and residual stress distribution model of the guide rail under the initial residual stress field were established,and the relationships between the curvature ratio of bending,the curvature ratio of straightening,bending moment ratio,rebound ratio and residual deflection were obtained.The accuracy of the initial residual stress distribution and the residual stress distribution after straightening were verified in the ABAQUS software.A straightening model based on least squares support vector machine was proposed.The material parameters: elastic modulus and yield strength were identified by least squares support vector machine.Then,the material parameters,straightening span and initial deflection were taken as input to establish the least squares support vector machine model based on genetic simulated annealing algorithm to predict the straightening stroke and residual stress after straightening,which lays a foundation for the development of high-precision automatic straightening equipment of Ttype guide rail.Finally,the experimental prototype system for T-type guide rail of straightness measurement and straightening control was designed,including hardware and software.The system can realize the functions of straightness measurement and straightening parameters prediction,and develop the database management system of theory,simulation and experiment data.The three-point bending straightening experiment of T-type guide rail was completed by using electronic universal testing machine,and the accuracy of straightening model based on least squares support vector machine was verified.The blind hole method for the residual stress test of the guide rail was completed by using static strain gauge,and the accuracy of initial residual stress distribution and residual stress distribution model after straightening was verified.The maximum residual stress after straightening can be predicted to a certain extent,which has the engineering practice significance.