Optimal tooling system design for large composite parts

The general objective of the project was to smartly handle the overall process of the composite integrated parts production, reducing costs in two ways. First, by adequately simulating the spring back produced after the curing process and providing solutions in order to reduce the costs of reworking or assembly. Secondly, by simulating the thermal model of the set tooling/composite part/vacuum bag and auxiliary parts under autoclave conditions to optimize the cure cycle temperatures distribution creating more uniformity in the composite part, lower residual stress, lower energy costs and better environmental friendliness. Given the large number of parts produced and their growth, the importance of the target is large.

For that general purpose, the first specific objective of the OPTOCOM project was to carry out all the necessary steps to design and manufacture large tool for a composite complex structural part, typically a double curvature fuselage stiffened panel with co-cured stiffeners of about 2x1sqm. The stiffening elements shall be of both “Z” type and “Ω” type cross section. Requirements such as high accuracy and rigidity, typical autoclave conditions, CTE matching, durability, minimal weight, provisions for transport, handling and accessories integration for easy demoulding, was imposed.

Secondly, was to develop analytical and FEM models which adequately simulate the distortions and spring back occurring in the curing process. This required to establish the correct hypothesis and to obtain real material performance behaviour both along the curing process and when the composite is cured, in order to be introduced into the model.

Third, was to set up FEM simulation models to assess the thermal behaviour and temperature evolution of the set of elements that get in the autoclave in order to optimise the thermal ramps and maps in the composite part.

Finally, an analysis of the design and manufacturing tooling costs to assess benefits and procedures was made.