Grid structures

A method of fabricating a grid structure of desired configuration from a composite material substantially consisting of filamentary material embedded in a matrix, said method comprising the steps of:

• a) arranging filamentary material according to a predetermined pattern to define interstices for said grid structure;
• b) covering each one of a plurality of mandrels individually with filamentary material consisting of fibrous filament, said mandrels conforming in cross-sectional configuration to said interstices defined by said pattern, said fibrous filaments being arranged on said mandrels so as to extend predominantly transversely with respect to said filamentary material arranged to define said interstices when said mandrels are inserted into said interstices;
• c) inserting said mandrels covered with said fibrous filaments into corresponding interstices defined by said pattern;
• d) causing said filamentary material arranged to define said interstices and said filamentary material covering said mandrels to be impregnated with a matrix material;
• e) applying compressional forces to said filamentary material impregnated with said matrix material between adjacent mandrels, said compressional forces being substantially entirely perpendicular to said fibrous filaments of said filamentary material covering said mandrels when said mandrels have been inserted into said corresponding interstices;
• f) curing said matrix material that has impregnated said filamentary material, thereby forming an integral structure made of said composite material consisting of said filamentary material embedded in said matrix;
• and
• g) removing said mandrels from said interstices.