강소성 유한요소법을 이용한 롤포밍 공정 해석

Abstract

Cold-roll-forming (CRF) is a well known process used to manufacture long sheet metal products with constant cross section. This process makes it possible to manufacture intricate sheet metal products which cannot be made through the press process. It is a very important process in many industrial fields to increase the application. However, the roll forming process is a difficult process because of the time and cost needed to prevent defects in the manufactured products. In order to solve this difficulty, computer analysis using rigid-plastic finite element method is being studied. The computer analysis method allows predicting final shapes and defects of the products through simulation and efficiently manufacturing the products. In this thesis, a under-rail composed of upper member, center member and lower member is designed and its roll forming process is simulated. Tensile test is performed about SCP-1 to obtain material properties and curve fitting is executed to set up the flow stress equation. The flower pattern of the upper member in the under rail is designed as three types. TYPE A is typical flower pattern used in design of U-channel. The cross-section of TYPE B and TYPE C is rotated in order to reduce the moment of inertia. The lower member is designed as TYPE-1 and TYPE-2. TYPE B and TYPE-1 are designed using the constant arc length forming method, and the TYPE C and TYPE-2 are designed using the constant radius forming method for excellent design. The roll forming process is simulated using SHAPE-RF software. The longitudinal strain is estimated on the basis of simulation results. In addition, the numerical magnitudes of camber and bow are predicted from the results of the simulation.