Effective Strains Determination in Continuous Constrained Double Bending with Active Friction Forces

In this work, a new process for severe plastic deformation (SPD) with active friction forces - CCDB Conform R3D2, a variation of the so-called "active bending", which is a continuous two-stage bending in calibers with small relative bending radius, is analyzed. A mechanical scheme of a device for realization of the process with a bending roller is proposed, based on a developed 3D virtual tool for its realization. Using CAD/CAE software 3D simulation, two virtual solutions of the process were compared, differing in terms of the location of the bending roller relative to the axes of the feeding and output rolls. The distribution and magnitude of the effective strains in the volume of the deformed long workpiece in the two bending stages at small relative bending radiuses were analyzed. An analytical expression is developed to determine the effective strains achieved in the SPD operation by constrained continuous bending in calibers with grooved rolls. The strain calculation methodology is based on the results obtained by simulation modelling of the CCB Conform R3D2 process in trapezoidal calibers with a bending roller located above and below the rolls line.