Development of composite materials reinforced with flat-knitted spacer fabrics

Flat-knitting technology has recently known spectacular developments with the advent of 3D spacer fabrics used as reinforcements of sandwich composites thanks to their improved mechanical properties. At present, studies dealing with the development and the characterization of these composites are quite rare .This work deals with the development of 3D-knitted composite using cotton yarn and unsaturated polyester resin. The aim of this work is to evaluate the utility of a natural reinforcement material in a technical use and assess the impact of fabric cross-link shape on composite mechanical performances. U- and V-shaped 3D spacer fabrics were produced and used to develop composite structures. These structures were characterized by flexion and flat compression tests. Results showed that composites reinforced with U spacer fabric have the best compression resistance whereas the best flexural properties were obtained with V-shaped fabric connection. The developed structures present competitive solution for light weight composites such as solar panels, blades of wind turbines, and sound absorbers.