Reshaping diagrams for bending straightening of forged aeronautical components

Abstract

Large and thick-walled aluminium forgings exhibit shape distortions induced by residual stresses. To restore the nominal geometry, a series of highly manual and time-consuming reshaping operations need to be carried out. In this paper, we are concerned with the development of efficient computer simulation tools to assist operators in bending straightening, which is one of the most common reshaping operations. Our approach is based on the computation of reshaping diagrams, a tool that allows selecting a nearly optimal bending load to be applied in order to minimize distortion. Most importantly, we show that the reshaping diagram needs not to account for the residual stress field, as its only effect is to shift of the reshaping diagram by some offset. That is, the overall behaviour including a realistic 3D residual stress field in a forged part can be retrieved by shifting the residual stress free reshaping diagram by the appropriate offset. Finally, we propose a strategy in order to identify the offset on-the-fly during the reshaping operation using simple force-displacement measures.