Optimization of Force and Power Imposed on Continuous Tandem Cold Rolling Rollers Using a Multiple-Function Genetic Algorithm

Mehdi Safari, Mohammadreza Moghoomi
2015 OALib  
The amount of energy consumed in the production lines such as cold rolled process is one of the fundamental problems in the energy infrastructure of manufacturing sectors. Accordingly, much attention should be directed towards optimizing the power consumption of production lines using reasonable methods. Furthermore, the powers exerted on such equipment must be modified to find an optimized energy consumption level. This study tries to examine the optimization of forces and powers imposed on
more » ... owers imposed on the continuous tandem cold rolling rollers of metal sheets using MATLAB and genetic algorithm. Firstly, some relationships and calculations of rolled metal sheets are analyzed. Then parameters, such as percentage of thickness reduction, mean pressure, yield stress, power of rollers and exerted torque, are calculated. All the governing relationships are programmed using MATLAB software. Having compared the mentioned two methods, genetic algorithm is used to determine the optimal required power. The results show that the optimized powers generated by genetic algorithm method are in good agreement with experimental observations. Also, the powers of rolling rollers and standard deviations of powers are calculated and, then, the two functions are compared and the optimum point between them is optimized. | Volume 2 | e1401 precision and very low thicknesses, the subject which is not possible in the hot rolling process. Nowadays, most cold rolling lines are designed continuously that are made up usually from 4 to 6 rolling shelves with four-roller. Surface of obtained cold-rolled sheets is harder and more smoothly than obtained hot-rolled sheets [1]. Sheets and belts obtained from cold rolling are manufactured in various thickness of less than 0.1 mm to 6 mm as coils or sheets, by mutual rolled or consecutive shelves. Also, in the cold rolling process, 25% to 90% reduction in thickness can be achievable [2] . In the cold rolling process, the main parameters such as thickness reduction at each stage of rolling, the size of the total reduction in thickness, width and thickness of the current sheet, constant thickness across the sheet, straightness of sheet surface, lubricate operations, tensile stresses of behind and front of the sheet, torque and each shelf rollers force, speed and coordination between the shelves should be carefully controlled in order to achieve a high quality sheet [3] . So far, many efforts have been made for metal forming, especially for cold-rolled steel sheets. In 2001, Venkada et al. [4] calculated the power consumption of rollers in the cold rolled process. Their results showed that the calculated reduction percentage in thickness of the sheet with 6 shelves roller, was in good agreement with report of Roberts. In 2000, Venga et al. [5] tried to achieve optimal planning design for continuous cold rolling process. They designed an algorithm based on the genetic optimization with the aim of optimizing the stress and speed. The results of distribution of power, stress and sheet flatness showed that optimized results were in good agreement with experimental observations. In 2008, Yang et al. [6] showed that the results of optimization algorithms were satisfied and good in comparison with other programs. In 2009, Vining et al. [7] considered the amount of carbon and carbide and reduction in the amount of rolling work as inputs of calculations to design a model that was able to predict at the same time and faster in an engineering environment. The output obtained from their studies suggested a set of parameters that were in a good agreement with experimental results. In 2004, Nivowski et al. [8] suggested an approximate analytical solution by introducing a nonlinear mathematical model for oscillation system of continuous rolling racks. Their study showed that the results of proposed analytical solution were comparable with rolling experimental parameters. In 2005, Weng et al. [9] by introducing an intelligent search mechanism for optimizing the planning with the assessment limitation of roll and the combination function of stress and distribution of power, achieved the maximum amount of rolling-work sheet safety. The model presented in this study, was able to solve multi-objective problems. In 2008, Pitner et al. [10] proposed a new method that used the Rikaty equation to control rolling process. In 2008, Dean et al. [11] used point-to-point, linear, quadratic method for optimal control of continuous cold rolling. To control the rollers, they used a new strategy to overcome the existing limitations, by designing multi-input and multi-output functions. Their results showed that the thickness of the output rolled sheet was between 0.5 onto 0.8 percent less than other studies, and caused stability of the rolling process. In Figure 1 , schematic of the cold rolling process is shown.
doi:10.4236/oalib.1101401 fatcat:gqlgh2rp4zgh5kcxlgab7e3754