Abstract: Method for making, modifying and using machinable composite molds for use in molding composite structures. The mold includes a mold body having a tool surface that is shaped to provide the molded surface of the composite structure. The mold body is made up of at least one mold layer composed of a quasi-isotropic material composed of a plurality of randomly oriented fiber bundles or chips impregnated with a resin. The use of randomly oriented fiber chips allows post-cure machining of the mold body.

Abstract: A composite material comprising at least one polymeric resin and optionally at least one fibrous reinforcement, where the polymeric resin comprises; at least one difunctional epoxy resin; and at least one epoxy resin with a functionality greater than two having at least one meta-substituted phenyl ring in its backbone.

Abstract: Pre-impregnated composite material (prepreg) is provided that can be molded to form composite parts that have high levels of both strength and damage tolerance without causing any substantial negative impact upon the physical or chemical characteristics of the uncured prepreg or cured part. This is achieved by including in the matrix resin a substantial amount of a multifunctional aromatic epoxy resin that has at least one phenyl group that is meta-substituted.

Abstract: Quasi-isotropic chopped prepreg is used to make parts found in aerospace vehicles. Exemplary aerospace parts that are made using quasi-isotropic chopped prepreg include aircraft window frames, wing fairing supports, flange supports, frame gussets, rudder actuator brackets, shear ties, seat pedestals, cargo floor flange supports, storage bin fittings, antenna supports, torque tube pans, handle boxes, side guide fittings, wing box covers and intercostals.

Abstract: A method for making a pre-impregnated composite material (prepreg) is provided. The prepreg can be cured to form composite parts that have high levels of damage tolerance. The matrix resin includes a thermoplastic particle component that is a blend of particles that have a melting point above the curing temperature and particles that have a melting point at or below the curing temperature.

Abstract: Epoxy resin compositions that include an epoxy resin component and a curative powder comprising particles of 4,4?-diaminobenzanilide (DABA) wherein the size of the DABA particles is less than 100 microns and wherein the median particle size is below 20 microns.

Abstract: A resin composition that is storable at ambient temperatures. The resin composition forms a cured resin when exposed to a curing agent and heated to a curing temperature that is relatively close to ambient temperature. The resin composition includes a crystalline resin component that is sandwiched between two non-crystalline resin components to provide a zone that is rich in crystalline thermosetting resin. The crystalline thermosetting resin has a melting point that is above ambient temperature, but below the curing temperature. The viscosity of the resin component changes from a high viscosity state to a low viscosity state when the temperature is increased from ambient temperature to the curing temperature.

Abstract: An acoustic structure that includes a honeycomb having cells in which septum caps are located. The septum caps are formed from sheets of acoustic material and include a resonator portion and a flange portion. The flange portion has an anchoring surface that provides frictional engagement of the septum caps to the honeycomb cells when the caps are inserted into the honeycomb during fabrication of the acoustic structure. An adhesive is applied to the anchoring surface of the septum caps after the caps have been inserted into the honeycomb cells to provide a permanent bond.

Abstract: An epoxy resin composition comprising an epoxy resin component combined with a sufficient amount of an imidazole curative to provide curing of the epoxy resin composition. The epoxy resin composition further includes a non-hydroxyl containing cure accelerator for the imidazole curative.

Abstract: Pre-impregnated composite material (prepreg) is provided that can be cured to form composite parts that have high levels of damage tolerance. The matrix resin includes a thermoplastic particle component that is a blend of particles that have a melting point above the curing temperature and particles that have a melting point at or below the curing temperature.

Abstract: Methods and apparatus are provided for making a rotor blade spar from composite material wherein a multi-component mandrel is used to form the composite spar. The mandrel is made using a number of components, which are assembled to provide a structure that is sufficiently strong to maintain the spar shape during pre-cure lay up, compaction and curing of the composite material. The multiple components used to form the mandrel can be separated from each other and easily removed from the spar either before or after curing of the composite material. The mandrel components can then be re-assembled and re-used to form additional composite spars.

Abstract: An uncured fiber reinforced assembly that includes a reinforcement layer containing a fibrous material and at least one highly reactive curing agent. A matrix film layer is applied to the reinforcement layer so that it does not substantially impregnate the reinforcement layer. The matrix film layer includes at least one uncured epoxy resin and at least one latent epoxy curing agent. The assembly is designed for use in making snowboards and skis.

Abstract: The invention concerns a process for making a scrim-reinforced prepreg for use in building low-porosity lay-ups, characterized in that a conventional prepreg is formed of a fibrous reinforcement and a heat-curable resin, the prepreg having suitable viscosity and sufficient tackiness to hold a scrim which is adhered to the prepreg by applying light pressure, so that the scrim is impressed onto the prepreg to such a degree, that less than half of the circumference of the scrim strands becomes coated by the prepreg-resin.

Abstract: A resin composition that is storable at ambient temperatures. The resin composition forms a cured resin when exposed to a curing agent and heated to a curing temperature that is relatively close to ambient temperature. The resin composition includes a resin component that is composed of a liquid part that is made up of one or more liquid thermosetting resins and a solid part that includes particles of one or more solid thermosetting resins. The liquid part further includes a gelation agent that is present in a sufficient amount to maintain the particles in suspension within the liquid part at ambient temperatures. The viscosity of the resin component changes from a high viscosity state to a low viscosity state when the temperature is increased from ambient temperature to the curing temperature. The high viscosity state is substantially more viscous than the low viscosity state.

Abstract: Corrosion resistant metallic honeycomb composed of a plurality of honeycomb cells having cell walls that include cell edges that form the edge of the honeycomb. A corrosion resistant coating that contains polyamideimide is used to cover the cell walls and cell edges. The corrosion resistant coating is preferably applied after the honeycomb structure has been formed.

Abstract: Method for making, modifying and using machinable composite molds for use in molding composite structures. The mold includes a mold body having a tool surface that is shaped to provide the molded surface of the composite structure. The mold body is made up of at least one mold layer composed of a quasi-isotropic material composed of a plurality of randomly oriented fiber bundles or chips impregnated with a resin. The use of randomly oriented fiber chips allows post-cure machining of the mold body.

Abstract: A resin composition that is storable at ambient temperatures. The resin composition forms a cured resin when exposed to a curing agent and heated to a curing temperature that is relatively close to ambient temperature. The resin composition includes a crystalline resin component that is sandwiched between two non-crystalline resin components to provide a zone that is rich in crystalline thermosetting resin. The crystalline thermosetting resin has a melting point that is above ambient temperature, but below the curing temperature. The viscosity of the resin component changes from a high viscosity state to a low viscosity state when the temperature is increased from ambient temperature to the curing temperature.

Abstract: Prepreg composite materials that include a fiber layer and a prepreg resin composed of a bismaleimide resin component, a thermoplastic toughening agent and a resin distribution stabilizer. The bismaleimide component is an amorphous mixture of at least three different bismaleimide monomers and a co-curing agent. The prepreg is useful in panel construction where a honeycomb core is sandwiched between two sheets of composite material.

Abstract: Aircraft floor panels where core-skin bonding is improved between honeycomb and composite face sheets (skins) by applying a nylon-based (polyamide) adhesive to the edge of the honeycomb prior to bonding. Edge coating of the honeycomb allows one to reduce panel weight without reducing the performance parameters that are required for different types of aircraft floor panels.

Abstract: Core-skin bonding is improved between honeycomb and composite face sheets by applying a polyamide and/or rubber-containing adhesive to the edge of the honeycomb prior to bonding. Edge coating of honeycomb with a polyamide and/or rubber-containing adhesive is useful in further increasing the bond strength between honeycomb and prepreg face sheets, especially when the matrix resin of the prepreg is designed to adhere the prepreg to the honeycomb without the use of a separate structural adhesive.