Stretch bending of aluminium extrusions for car bumpers

Stretch bending of two generic aluminium bumper sections are investigated e xperimentally and numerically. Six different stretch bending procedures, he rein denoted tensile sequences, are studied. Laboratory tests are performed for one of these sequences, finding that the numerical model represents th e observed behaviour satisfactorily. A sequence with constant tensile force during bending seems to be favourable with respect of cross-section deform ations. These deformations increase with additional tensile force, whilst t he springback during unloading shows a decreasing tendency. Post-stretching operations or membrane-induced stretch bending are also investigated, find ing that these sequences result in a disadvantageous cross-section distorti on. (C) 2000 Elsevier Science S.A. All rights reserved.