FEM Analysis And Experimental Research On Cold Roll Forming

Cold roll forming is a complicated sheet and strip steel manufacturing method and an important field with high additional value. But now forming mechanism has not been studied clearly. The main purpose of this paper is to research on forming mechanism. On the basis of experimental results, using FEM (finite element method) analysis this paper research extensively on the process of cold roll forming from the mechanical analysis of steel sheet.Firstly, this paper introduced and evaluated the development and accomplishment of cold roll forming at the present in china and outside. Then, the features, theories, FEM analysis and CAD technology of cold roll forming were depicted explicitly.Secondly, when the deformational mechanism of cold roll forming was analyzed, interrelated nonlinear theories were introduced and summarized. And applying nonlinear FEM, this paper analyzed simply the process of cold roll forming.Based on mechanical and deformational character of the process of cold roll forming, the author designed and machined the testing device of cold roll forming. Its configuration is simple and cost is low. Stains and rebounding value of steel sheet are tested easily by using this device.Using this testing device, the author tested strains and rebounding value of testing steel sheets whose thickness is 4mm and 6mm.The testing data accord basically with theoretical results and reflect correctly the transverse deformational characteristic of steel sheet during the process of cold roll forming.Using the software of ANSYS/LS-DYNA, this paper created the testing sheet model, simulated the process of testing, and studied how stresses and strains of every testing point changed when distorting angle changed. Moreover, this author analyzed other factors of testing sheet model affecting on the distribution of strains and stresses, such as solution time, thickness of sheet, denseness of the FEM meshes, angle of dies, length ofsheet wings, etc. The FEM analysis results of testing sheet is consistent with experimental data.In the ANSYS/LS-DYNA module, the author created roller model using SHELL163 element and rigid body material model, created sheet model using SHELL163 element and classical bilinear isotropic hardening model and simulated the process of one-step, two-step, and many-step cold roll forming. Then the author researched on the distribution of stresses and strains of forming sheet. The FEM model of forming sheet simulated actually transverse deformation and longitudinal deformation of forming sheet. Transverse deformation accords well with experimental data of testing sheet, but longitudinal deformation is little different from actual production.Additional, using SOLID164 element, the author created models simulating test of roll forming and process of two-step roll forming and studied the distribution of stresses and strains along the thickness of sheet. The deformational feathers of the solid sheet model are consistent with the sheet model created using shell elements.At last, the conclusions are drawn and the useful recommendation and perspectives are put forward.The conclusions of this paper are as follows: The testing device of cold roll forming designed independently reflects accurately the characters of transverse deformation of forming sheet during the process of cold roll forming; The FEM model of sheet is reasonable and accords with actual production; It is practical and feasible to use the software of ANSYS/LS-DYNA simulating the process of cold roll forming; The studies of this paper are vital to promote theoretical research and to guide actual production of cold roll forming.