This paper, relying on a developed flower pattern and a geometric model based on the involute curve, investigates the strain stress behavior, the gradual load transfer and the possibility of geometric and mechanical defects in the two processes. The aim is to present an analytical-numerical method for accurately comparing the forming steps, determining the position and angle of the rollers and analyzing the effect of the proposed arrangement on improving the mechanical response of the sheet. The working method includes developing the developed flower pattern, extracting the involute equations, determining the configuration of the five-station rollers by numerical solution in MATLAB and analyzing the stress-strain analysis with a 3D Abaqus model. By comparing the cross section of sheet obtained from the method and that of another reference, validation of the method was confirmed. The equivalent strain study at the first station indicated that the conventional roll forming process produces 15% more strain in the edge area than the flexible process. Also, the longitudinal strain in critical areas such as the edge is 79% lower in the flexible roll forming process than in the conventional roll forming process. The average values of stress obtained show that the flexible roll forming process produces a 27% reduction in stress compared to the conventional one. By gradual control of curvature and more uniform distribution of loading, in the flexible roll forming process not only reduces critical strains, but also effectively reduces the possibility of defects such as edge cracking, local thinning and cross-sectional distortion.

Computer aided simulation of three-dimensional deformation behavior of sheet metal during cold roll forming process is described In this simulation, the shape of deformed sheet metal is expressed by an approximated mathematical equation called "Shape Function". By means of this shape function, stress and strain distribution and dissipated energy in the deformed sheet metal can be calculated by a computerized incremental procedure using Hooks law in the elastic range and Levy - Mises equations in the plastic range. The optimum shape of deformed sheet can then be predicted by minimization of the calculated energy.By the simulation, it was possible to explain various characteristics of the cold roll forming process. The authors believe that using Levy - Mises equations simplifies the previously proposed methods and at the same time the results seem to be quite encouraging.