Numerical Simulation of the four roll bending process

Recent aircraft designs have illustrated that metallic fuselage structures will remain for the foreseeable future. Nevertheless, due to material variability and serrated yielding, accurate manufacture of large single and double curvature fuselage panels requires an alternative approach. The traditional four roll bending process is currently limited to the production of cylindrical and conical forms with a predetermined path for the workpiece and little or no compensation for material variability. This article describes a prototype, modular, four roll bending machine with extensive instrumentation that provides a means to compensate for the aforementioned variability and limitations. A finite element (FE) modelling methodology is presented and validated by comparison with force and curvature measurements from the machine. Excellent agreement was found between the experimental results from the prototype machine and the modelled output for single curvature forming.