Fastener systems and methods for joining multiple substrates of workpiece

A method for joining multiple substrates of a workpiece, the workpiece having a working side and a blind side, the method comprising:

• inserting a binding barrel member in a joining bore through at least one substrate of the multiple substrates from the blind side of the workpiece, the binding barrel member comprising a cylindrical barrel body with a proximal end, a distal end and a central bore in the cylindrical barrel body, the central bore comprising a counterbored barrel portion and a threaded barrel portion with internal threads, the binding barrel member further comprising a barrel flange adjacent to the distal end of the cylindrical barrel body, the barrel flange configured to limit further insertion of the binding barrel member into the joining bore, the cylindrical barrel body further comprising an outer barrel surface with a lubricious coating;
• inserting a bolt member in the joining bore through the multiple substrates from the working side of the workpiece until a distal end of the bolt member contacts the binding barrel member, the bolt member comprising a head portion, a threaded bolt portion and a shank portion extending between the head portion and the threaded bolt portion;
• rotating the bolt member to engage the threaded bolt portion with the internal threads of the binding barrel member;
• radially expanding the binding barrel member within the joining bore through the multiple substrates as the bolt member becomes fully engaged with the binding barrel member;
• and
• providing an interference fit for the binding barrel member within the joining bore through the multiple substrates in response to radial expansion of the binding barrel member as the bolt member becomes fully engaged with the binding barrel member, and
• wherein an outer threaded diameter for the threaded bolt portion of the bolt member is substantially greater than an inner threaded diameter for the threaded barrel portion of the binding barrel member.

A fastener system for joining multiple substrates of a workpiece, the multiple substrates comprising at least one composite material substrate, the workpiece having a working side and a blind side, the fastener system comprising:

• a binding barrel member comprising a cylindrical barrel body with a proximal end, a distal end, a central bore in the cylindrical barrel body with internal threads and a barrel flange adjacent to the distal end of the cylindrical barrel body, the central bore comprising a counterbored barrel portion and a threaded barrel portion with internal threads, the binding barrel member configured for insertion in a joining bore through at least one substrate of the multiple substrates from the blind side of the workpiece, the barrel flange configured to limit further insertion of the binding barrel member into the joining bore, the cylindrical barrel body comprising an outer barrel surface with a lubricious coating;
• a cap sealant member comprising a dome and a cap flange, the cap sealant member configured for placement over the binding barrel member, the cap flange configured to secure the cap sealant member to the blind side of the workpiece;
• and
• a bolt member comprising a head portion, a threaded bolt portion and a shank portion extending between the head portion and the threaded bolt portion, the bolt member configured for insertion in the joining bore through the multiple substrates from the working side of the workpiece until a distal end of the bolt member contacts the binding barrel member, the threaded bolt portion configured for threaded engagement with the internal threads of the binding barrel member after contacting the binding barrel member,
• wherein an outer threaded diameter for the threaded bolt portion of the bolt member is substantially greater than an inner threaded diameter for the threaded barrel portion of the binding barrel member, and
• wherein, as the bolt member becomes fully engaged with the binding barrel member, the bolt member is configured to cause radial expansion of the binding barrel member and the binding barrel member is configured to provide an interference fit within the joining bore through the multiple substrates.