A resin-rich peel ply that does not leave behind residual fibers after peeling and can work well with different resin-based composite substrates. The resin-rich peel ply is composed of a woven fabric impregnated with a resin matrix different from the resin matrix of the composite substrate. The peel ply is designed such that, upon manual removal of the peel ply from the composite substrate's surface, a thin film of the peel ply resin remains on the composite substrate's surface to create a bondable surface capable of bonding with another composite substrate, but no fibrous material from the woven fabric remains on the same surface.

Methods and apparatus for tooling in layered structures for increased joint performance are disclosed. A disclosed example method includes placing a tool onto a first substrate to define an impression in the first substrate, curing the first substrate, removing the tool from the first substrate to define a joint interface corresponding to the impression, and coupling, at the joint interface, the first substrate to a second substrate.

An object is to provide a metal-resin bonded member that is easy to manufacture and has high bonding strength. The metal-resin bonded member includes a metal body having an iron oxide layer on the surface and a resin body bonded to the metal body via the iron oxide layer. The iron oxide layer has a thickness of 50 nm to 10 m. The iron oxide layer comprises 60-40 at % Fe and 40-60 at % O at the outermost surface side. The iron oxide layer contains magnetite (Fe.sub.3O.sub.4). The iron oxide layer is formed by heating the surface of an iron-based substrate at 200-850 C. in an oxidation atmosphere. The resin body is composed of polyphenylene sulfide (PPS). The bonding of the metal body and the resin body via the iron oxide layer can be carried out by insert molding, thermal adhesion utilizing friction heating, etc.

A conductive fastener system for connecting a composite structure to a support structure includes a composite structure hole that extends through the composite structure and shares a common axis with a support structure hole that extends at least partially through the support structure. A fastener comprising a shank having an outer surface passes through the composite structure hole and at least partially through the support structure hole and provides an annular space between the outer surface of the shank and the inner surface of the composite structure hole. The annular space is filled with a conductive paste that comprises conductive particles suspended in a bonding agent.

An adhesive (B) of solvent containing adhesive as a suspension of low viscosity is prepared by adding a solvent MIBK to a one-part epoxy adhesive of a dicyandiamide-curable type (A). Metal shaped articles (M1 to M5) as adherends are prepared each of which, through various surface treatment, has specific surface configuration of roughened face and/or ultrafine irregularities and the surface is entirely covered with a thin layer of ceramics such as a metal oxide or metal phosphate. The specified face of each metal shaped article (M1 to M5) is painted with the solvent containing adhesive (B). The faces painted with the adhesive of two metal shaped articles (M1 to M5) are caused to abut each other, the articles are heated to cure the one-epoxy adhesive to accomplish adhesion. With one of the adherends replaced by a CFRP shaped article (P2), a composite of a metal and CFRP can be formed.

Methods and apparatus for tooling in layered structures for increased joint performance are disclosed. A disclosed example method includes placing a tool onto a first substrate to define an impression in the first substrate, curing the first substrate, removing the tool from the first substrate to define a joint interface corresponding to the impression, and coupling, at the joint interface, the first substrate to a second substrate.

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.

An adhesive (B) of solvent containing adhesive as a suspension of low viscosity is prepared by adding a solvent MIBK to a one-part epoxy adhesive of a dicyandiamide-curable type (A). Metal shaped articles (M1 to M5) as adherends are prepared each of which, through various surface treatment, has specific surface configuration of roughened face and/or ultrafine irregularities and the surface is entirely covered with a thin layer of ceramics such as a metal oxide or metal phosphate. The specified face of each metal shaped article (M1 to M5) is painted with the solvent containing adhesive (B). The faces painted with the adhesive of two metal shaped articles (M1 to M5) are caused to abut each other, the articles are heated to cure the one-epoxy adhesive to accomplish adhesion. With one of the adherends replaced by a CFRP shaped article (P2), a composite of a metal and CFRP can be formed.

A bonding preparation patch for application to a resin treated surface is provided. The patch includes a strip having first and second portions, each of which has corresponding first and second sides. The strip is formed of resin porous material and is foldable such that the respective first sides of the first and second portions face each other. The patch further includes a resin barrier interposable between corresponding portions of the respective first sides and a tape including at least one adhesive side, which is securable relative to the first portion and disposable in contact with the second side of the second portion.

Peel ply for surface preparation and a method of surface preparation prior to adhesive bonding. A resin-rich peel ply is applied onto a curable, resin-based composite substrate, followed by co-curing. After co-curing, the composite substrate is fully cured but the matrix resin in the peel ply remains partially cured. When the peel ply is removed, a roughened, bondable surface with chemically-active functional groups is revealed. The composite substrate with the chemically-active, bondable surface may be bonded to another composite substrate to form a covalently-bonded structure.