An extruded structural member having improved damage tolerance containing a base
section (6); a stiffening section having at least one pair of structural
stiffeners (10), the structural stiffeners integral with the base section
(6) and projecting outwardly thereof; and at least one intra-stiffener (90)
area positioned between the pair of structural stiffeners (10), the intra-stiffener
area (90) having a microstructure with intentionally increased amounts of
fiber texture to reduce the rate of fatigue crack growth in the extruded structural member.