Optimization Of Structural Parameters And Simulation Analysis Of Different Roll Pitch Steel Straightening Machine

As a finishing technology,straightening is becoming increasingly important and has become an important branch of metal processing.As an emerging straightening technology,the different roll pitch straightening perfectly combines the advantages of equal and variable roll pitch straightening technology,with the advantages of high straightening accuracy,wide application range and easy operation.However,there is still a common problem of uneven wear of the straightening rollers caused by the large difference in straightening force between the rollers,which seriously restricts the service life of the straightening machine,so it is necessary to carry out systematic theoretical research on the straightening of the different rollers and to optimise their structural parameters.The main research content is as follows.(1)In this thesis,according to the technical characteristics of different roll pitch straightening,determine the combination of large and small deformation straightening program.In response to the problems that arise when large and small deformation straightening solutions are used separately,a combination of large and small deformation straightening solutions is proposed,which perfectly solves the problem of contradicting the stiffness and strength of the straightening rollers when they are arranged.(2)The number of rolls,roll spacing and roll diameter are initially optimised separately.Optimisation of the number of rolls is completed using the theoretical straightness achievable for the bars after straightening as a reference.The range of roll spacing is determined by combining factors such as contact strength,bite in conditions and straightening quality.The straightening force applied by the straightening rolls is used as the independent variable and the sum of the straightening forces for each roll is used as the objective function to optimise the roll spacing using the fmincon function in MATLAB software.Compared to the original equal roll pitch straightening machine,the optimized straightening system has a more balanced force on the straightening rolls and a smoother process,which effectively reduces the wear difference between the straightening rolls and increases the service life of the straightening machine.In addition,in order to give the straightener a better straightening effect,the influence of the size of the rear rollers on the straightening accuracy was also investigated.(3)Particle swarm optimization is used to optimize the structural parameters of the straightening system.The straightening structure obtained by combining the optimal solutions of each variable does not necessarily achieve the optimal straightening effect.Therefore,particle swarm optimization algorithm is used to optimize the structure of straightening system in this thesis,and the structural factors such as roll number,roll diameter and roll distance are fully considered.Optimisation is carried out with the objective function of minimising the stress fluctuations in the straightening rollers during the straightening process,to change the status quo of uneven stresses leading to varying wear of the straightening rollers and to reflect more intuitively the advantages and disadvantages of the straightening structure through the comparison of function values.The model is built according to the best result parameters,and the process of steel bar straightening is simulated by ANSYS Workbench software.The straightening forces and straightness of the bars after straightening are evaluated by looking at and comparing the straightening forces and straightness of the bars obtained by the two ideas of univariate optimization and particle swarm multivariate optimization.The results show that the sum of the straightening forces is smaller and the straightening effect is better with the improved particle swarm algorithm.(4)On-site testing of the straightening force of the upper row of rolls on the different roll pitch straightening machine.In order to accurately verify whether the theoretical values of the straightening force are pushed to the correct level,the force at each straightening roll of the straightening machine is measured experimentally and the results matched the theoretical values.In this thesis,the theoretical,simulation and experimental analysis methods are used to study the straightening structure parameters.The optimization of the straightening structure parameters is realized,and the service life of the straightening machine is improved.The research results can provide the basis for the design of the straightening machine.