Optimization Of The Energy Efficiency During Cold Roll Forming By Simulation

Cold roll forming(CRF) is a sheet metal forming process for the mass production of a variety of complex profiles steel. The researches on the energy efficiency of such a continuous bending process promise a significant reduction in energy consumption. However, most previous works focused on how to improve the product quality of the sections and few works have addressed the energy efficiency. In this thesis, an energy efficiency index is introduced, i.e.,the ratio of the production rate to the energy consumption, to evaluate the energy consumption for CRF. By orthogonal simulation experiments and quadratic regression orthogonal experiments, the influences of the inter-distance among the adjacent rollers, forming velocity, height difference between the adjacent rollers were investigated. The strain and stress distributions were simulated by employing the forming parameters under the optimum energy efficiency index.The sizes of the formed sections were compared with the ideal section sizes based on the simulation results.A 3-dimension model for finite element simulations was built by ABAQUS software based on the roller flowers of a column plate section. The CRF processes of the column section were simulated under the given analysis steps,boundary conditions and contacts. The orthogonal experimental data of the ALLIE curves about the energy consumption and energy efficiency index were obtained by simulation. The results of simulation show that the most critical process parameters influencing on the energy efficiency of CRF are the inter-distance among the adjacent rollers and the forming velocity. Then the quadratic regression orthogonal experiments were conducted by using the two parameters as independent variables and the energy efficiency index as the dependent variable. A regression equation was obtained based on the experimental results. It is shown that the optimum process parameters of CRF are the inter-distance among the adjacent rollers of 600 mm, the forming velocity of 9m/min and the height difference between the adjacent rollers of 7.5mm by solving the maximum value of the regression equation in the ranges of these independent variables. The contours of stresses show that the maximum andrelatively large stresses occur at the positions where the rollers and plates contact. The contours of strains show that the plastic strain is larger than 0 at the edges, indicating the occurrence of yielding. The simulation results are consistent with the actual forming situations. The longitudinal stains at the edges of the profiles are very small. The size difference between simulated cross-sections and the ideal sections is less than 3mm, which meets the engineering requirements.