Abstract: A blind fastener is provided comprising a core bolt comprised of a bolt shaft and a bolt head. A metal sleeve is included comprising a rigid cylindrical base and a malleable cylindrical tail, the metal sleeve is positioned around the bolt shaft with the malleable cylindrical tail in communication with the bolt head. A travel stop feature is formed on the rigid cylindrical base opposite the malleable cylindrical tail. A drive feature includes a threaded bolt section extending from a foot end of the bolt shaft and a drive nut rotatably thereto. The drive nut allows the core bolt to be pulled within the metal sleeve such that the bolt head compresses the malleable cylindrical tail to form a retention button.

Abstract: A variety of a damage-tolerant monolithic structures are disclosed, such structures having a substantially-planar element integral with or welded to one or more stiffening elements. Each stiffening element can includes a first stiffening flange having a generally rail-like structure running along the length of the planar element and one or more webbings connected to the planar element and extending away from the planar element to the stiffening flange, wherein each webbing includes a row of integral holes running along the length of the webbing, the holes being in a shape designed to hinder the propagation of a crack in the monolithic structure.

Abstract: A variety of a damage-tolerant monolithic structures are disclosed, such structures having a substantially-planar element integral with or welded to one or more stiffening elements. Each stiffening element can includes a first stiffening flange having a generally rail-like structure running along the length of the planar element and one or more webbings connected to the planar element and extending away from the planar element to the stiffening flange, wherein each webbing includes a row of integral holes running along the length of the webbing, the holes being in a shape designed to hinder the propagation of a crack in the monolithic structure.

Abstract: Extended fatigue endurance and high pre-load are achieved in a structural blind fastener by combining the best features of screw type and pull type blind fasteners. We replace fatigue critical details from the shear plane with close tolerance, slip fit, core bolt and outer bolt shanks to obtain the desired structural load paths while retaining anchoring features of screw type fasteners to introduce adequate pre-load. These fasteners are compatible with currently available blind bolt insertion tooling.

Abstract: We achieved extended fatigue endurance and high pre-load in a structural blind fastener by combining the best features of screw type and pull type blind fasteners. We replaced fatigue critical details from the shear plane with close tolerance, slip fit, core bolt and outer bolt shanks to obtain the desired structural load paths while retaining anchoring features of screw type fasteners to introduce adequate pre-load. Our fasteners are compatible with currently available blind bolt insertion tooling. The present invention pertains to a lightweight version of the structural blind fastener wherein we set the backside anchor collar with matching threads that engage between the outer sleeve bolt and inner core bolt.

Abstract: A flaw growth correlator for monitoring flaw growth potential in a structural body. The correlator providing a major increase in the sensitivity of flaw growth when compared to current designs of constant thickness crack gauges.