An Industrial Application of the Continuum Damage Mechanics (CDM) Model for Predicting Failure of AA6082 under HFQ® Process

The failure prediction for forming of high strength complex shaped panel made of AA6082 aluminium alloy during the solution heat treatment cold die forming and quenching process (HFQ®), is presented. Experimental trails have been carried out to optimise the blank shape on the success of forming the complex-shaped aerospace panel component (wing stiffener part). Using the traditional set of uniaxial constitutive equations is difficult to predict the forming features in real hot stamping, especially taken the varied stress states during the forming process. A multi-axial viscoplastic constitutive model based on continuum damage mechanics (CDM) has been developed to describe the deformation behaviour of aluminium alloys under hot/warm stamping conditions. By linking such CDM-based constitutive equations into complete finite element solver, PAM-STAMP in this case, via external Subroutine, as a User Defined Material (UDM), the formability for any process conditions, cold or hot and low or high speed, could be predicted. In this paper the CDM model is verified using an experimental forming trail of complex aluminium component. The results show that the CDM model can be used to provide accurate formability and failure predictions.