Abstract: An open-channel stiffener for stiffening a panel has a bonding flange for bonding the stiffener to the panel through a bondline formed between the bonding flange and the panel to form a stiffened panel. The open-channel stiffener has a cross-sectional shape that aligns, or substantially aligns, a shear center of the stiffener with a centroid of the stiffener and aligns the shear center proximate an edge of the bondline, and removes the need for a radius filler noodle. A plurality of perforations may be formed through the bonding flange to permit an adhesive to wick into the perforations and create a mechanical interlock between the bonding flange and the panel.

Abstract: Method for measuring residual strain in a cured composite part includes taking a first image of at least two spaced apart particles positioned on a side of the cured composite part with the side positioned transverse to a first face side. The cure composite part includes a first ply has fibers and a second ply has fibers wherein the first ply and the second ply are positioned in overlying relationship to one another. At least a portion of the fibers of the first ply are positioned in angular relationship with at least a portion of the fibers of the second ply. The at least two spaced apart particles are associated with the second ply. Further included is a step of removing at least a portion of the first ply and taking a second image of the at least two spaced apart particles.

Abstract: An open-channel stiffener for stiffening a panel has a bonding flange for bonding the stiffener to the panel through a bondline formed between the bonding flange and the panel to form a stiffened panel. The open-channel stiffener has a cross-sectional shape that aligns, or substantially aligns, a shear center of the stiffener with a centroid of the stiffener and aligns the shear center proximate an edge of the bondline, and removes the need for a radius filler noodle. A plurality of perforations may be formed through the bonding flange to permit an adhesive to wick into the perforations and create a mechanical interlock between the bonding flange and the panel.

Abstract: A composite structure having a base charge and an outer channel charge is provided. The outer channel charge has an inner radius and an outer radius. A charge of plies adjacent to the inner radius reduces the inner radius.

Abstract: A composite structure having a base charge and an outer channel charge is provided. The outer channel charge has an inner radius and an outer radius. A charge of plies adjacent to the inner radius reduces the inner radius.