Influence of Element Types on Springback Prediction of Creep Age Forming of Aluminum Alloy Integral Panel

Abstract

Creep Age Forming (CAF) is an effective forming technique combined forming and heat treatment, based on creep and age hardening characteristics of some aluminum alloys. It has been widely used to manufacture large integral panels with airfoil sections and complex curvatures of high strength aluminum alloy. The aim of this paper is to study the influence of element types on springback prediction of creep age forming of aluminum alloy integral panel. Firstly, the finite element models are built by 3D-solid elements and Shell elements separately. And then a set of creep aging constitutive equations of 7055 aluminum alloy are implemented into the commercial FE solver MSC.MARC through user defined subroutine. Finally, springback values predicted by 3D-solid elements model and Shell elements model respectively are compared under different height to width ratios. Some important conclusions were drawn. For the reinforcing panel with the height to width ratio is more than 5:1, shell elements should be used to get more accurate springback prediction result. If the height to width ratio is less than 5:1, solids elements should be used. Above conclusions provide theoretical basis for the study of CAF of the aluminum alloy integral panel by finite element simulation method.