Four-directional structure for reinforcement

A 4-directional reinforcement structure for a composite material which comprises a plurality of repeating units, each unit consisting of a first, a second, a third and a fourth group, each group consisting of a plurality of elongated rectilinear elements in parallel relation and extending parallel to a respective direction and arranged in a plurality of rows;

• wherein a first portion of said first group of elements is disposed in a first plane and extends parallel to a first direction;
• wherein said second group of elements is disposed in a second plane parallel to said first plane, said second group extending parallel to a second direction which is approximately diagonal to said first direction;
• wherein a second portion of said first group is disposed in a third plane parallel to said first plane and extend parallel to said first direction;
• wherein said third group of elements is disposed in a fourth plane parallel to said first plane and extend parallel to a third direction which is approximately diagonal to said first direction and opposite the orientation of said second direction;
• and wherein said fourth group of elements is disposed in a plurality of spaced parallel planes, each plane being substantially perpendicular to said first direction, said fourth group extending parallel to a fourth direction which is substantially perpendicular to said first plane.