Development of the manufacture of complex composite panels

Composite reinforcements can be difficult to form manually over complex geometries due to difficulties arising from the types of drape mechanisms available. Often more than one can be found in action, and different geometrical features require specific formability characteristics. This is true when manufacturing composite sandwich panels and particularly so if the structure includes cut–outs as these features are very difficult to form. Forming complexities can also be found in automated methodologies, particularly when relatively complex parts are manufactured, as the techniques attempt to minimise manual operations. Development towards automated manufacturing therefore requires: 1) reappraisal of the most appropriate deformation properties in reinforcements; 2) methods to achieve them reliably. This paper examines those requirements and presents simple examples that aim to enhance formability. It also presents novel concepts of tow steering and pin–bed preforming that take an alternative approach to drape by reorganising the material according to the panel design offline. The details of both concepts are explored and examples show their potential for use in complex geometry manufacture. The paper concludes that both concepts are suitable processes for future development to enable automated lay–up.