Paper number 264

MECHANICAL IN PLANE PERFORMANCE OF AEROTISS ( 4/5D)

Henk Pattyn¹, Ignaas Verpoest¹, Jan Ivens¹,

Sylvie His 2, Georges Cahuzac 2
1Department of Metallurgy and Materials Engineering, KULeuven,
de Croylaan 2, B-3001 Leuven, Belgium
2Aerospatiale Aquitaine, Département Composites Froids,
B.P. 11, F-33165 St Medard en Jalles, France

Summary

Aerotiss( 4/5D ) is a technique to produce thick, multi-layered preforms, reinforced through the thickness by stitching. The stitching guarantees the stability of the preform during processing. Moreover, it gives the final composite an excellent delamination resistance and fracture toughness. RTM was used to impregnate the preforms with an epoxy resin system. The influence of the stitching on the mechanical in plane performance was studied for quasi-isotropic glass and carbon preforms. Smaller stitch spacing causes a slight decrease in stiffness and a certain decrease in strength. This is more pronounced for the carbon preforms. The stitches act as stress concentrators during loading. Computer tomography revealed that the fibres in the 0°/90° layers remain straight, but that in the +/-45° layers, the stitching causes undulation. A geometric model is being developed to refine the laminate plate model for these Aerotiss( 4/5D )composites.

Keywords

aerotiss( 4/5D ), mechanical in plane performance, stitching, quasi-isotropic preforms, laminate plate model, computer tomography, glass-epoxy, carbon-epoxy.