Optimization of pipe bending parameters using flexible wire-mandrel

Bent pipes have been widely used in industries such as aviation, aerospace, ship building, automobile, installation and so on. There is several ways to improve bending quality; common mandrels and hydro forming are technologies which are relatively expensive. Conventional Mandrels need accurate adjustments which directly affect bending quality. Sometimes after bending process it is difficult to take mandrel parts out from inside of the bent pipe and it needs to special hydrolytic system. In this work different materials have been used as mandrel and it is realized that a bunch of flexible wire is more preferable than other materials to optimize bending parameters. This way doesn’t need laborious adjustments and because common flexible wires have plastic deformation even during excessive bending angles, they can be used so many times and also they are easy to remove after bending process, even with the help of one hand. Cross section distortion, cracking at the extrados, wrinkling at the intrados, spring back phenomenon and wall thickness change are issues associated with pipe bending. In this work the effect of flexible wires on bending parameters has been analyzed and the results are confirmed with finite element simulation.

Keywords:

pipe bends , flexible wire , cross section distortion , spring back , wall thickness change