Plastic-deformation analysis in tube bending

Plastic-deformation theory is employed to investigate the plastic deformati on in pipe and tube bending. The major contribution of this paper is that i t provides solutions to seven common tube-bending questions. In this paper, some practical formulae are developed to explain the phenomena in tube ben ding and their magnitudes are also derived. These are: (1) stresses in the bend; (2) wall thickness change; (3) shrinking rate at the tube section; (4 ) deviation of neutral axis; (5) feed preparation length of the bend; (6) b ending moment, and (7) flattening. An experimental sample was also tested t o illustrate that the results of the formulae are very similar to the exper imental results. (C) 2001 Elsevier Science Ltd. All rights reserved.