Modeling and optimization of stretching for double curvature fuselage panel

Stelia Aerospace, one of the world leaders in aerostructures, uses the stretching process to form fuselage panels for their customers. This process is a cold and quasi static process to provide large double curvature panels. Generally, the panels are formed in several steps in order to obtain a compliant panel.

Since few years, Stelia Aerospace develops process simulations particularly the stretching process. The aims of these developments are to sustain the production of Stelia Aerospace, to improve the productivity, validate the feasibility and contribute to developments of new products of Stelia Aerospace.

The aim of the simulation is to show the modeling methodology is allow to be representative of the reality in order to obtained a virtual manufacturing test. In the case of stretching process, the modeling is exploited to predict the stress and the strain during the operation of stretching, as well as the spring back on panel. This virtual test will have allowed the optimization of manufacturing program.

This developments combines, firstly, work of modeling the stretch forming machine and validate its representativeness. During this first step, we conducted some tests on the machine. We used the stereocorrelation to follow the strain during forming and we controlled the panel geometry after springback. The data is then used to correlate with the modeling. Secondly, we worked on the automating of the optimization of the manufacturing program in order to achieve a single stretch forming process for double curvature panel. On the optimization step, Stelia Aerospace uses Hyper study features to automate to search for an optimum.