Diaphragm forming of resin pre-impregnated woven carbon fibre materials

In the aerospace industry, traditional hand laminating and shaping methods for manufacturing continuous fibre reinforced polymer composites must give way to mechanical forming methods. The CRC for Advanced Composite Structures has developed the Double Diaphragm Forming process to efficiently form flat composite stacks into double-curved shapes. This paper looks at the deformation mechanisms available in composite reinforcement stacks, and how these influence the forming methods required. Some tests used to characterise the properties of epoxy-impregnated carbon fibre fabrics, and some typical results are described. Examples of numerical simulation of forming processes using the PAM-FORM modeling software are given. A short discussion of parts that have been formed using double diaphragm fori-ning is included.