Abstract: A preform suitable for use in a resin transfer molding process comprising (1) one or more layers of a non-woven random mat and (2) one or more layers of a series of tows of unidirectional fibers held together by a polymeric curable resin film grid. The polymeric resin film is in the form of a grid, such that only a fraction of the surface area of the fibers contacts the resin film.

Abstract: A system and method for simulating LCM mold filling utilizes at least one processor, suitable RAM and storage memory, a data input, a display, and logic for simulating the injection of resin into a mold cavity containing a preform based upon mold cavity design parameters, mold filling processing parameters, physical property parameters, and system processing parameters, and identifying the current state of selected mold filling conditions at selected points in time during the simulated mold filling process. The system logic includes an error estimator for periodically estimating the error in the flux computations, preferably during each iteration in the solution of the governing equations. The system also preferably includes predictor/corrector logic which modifies a variable relaxation parameter and a variable convergence tolerance, based upon the estimated error and other predefined computational thresholds to urge rapid convergence to a correct solution of the governing equations in an efficient manner.

Abstract: A process for preparing a matrix resin composite contains the steps of: (1) preparing a preform containing multiple layer of reinforcing material and a crosslinkable tackifier by (a) applying the tackifier onto the reinforcing material, (b) compressing the layers of reinforcing material and partially crosslinking the tackifier under a pressure sufficient to compact the tackified, reinforcing layers to a volume which is less than their volume in the finished composite part and in a manner such that at least one surface of each of the reinforcing layers is or will be, during partially crosslinking, in direct contact with the tackifier, and (2) contacting the preform with a matrix resin.

Abstract: An improved process to make composites contains the steps of: (1) partially curing a tackifier resin in contact with a substrate to form a shapeable preform; (2) adding a matrix resin and co-curing the tackifier and matrix resin to form a composite. The resulting composites are useful in structural applications.

Abstract: A system and method for simulating LCM mold filling utilizes at least one processor, suitable RAM and storage memory, input means, display means, and logic for simulating the injection of resin into a mold cavity containing a preform based upon mold cavity design parameters, mold filling processing parameters, physical property parameters, and system processing parameters, and identifying the current state of selected mold filling conditions at selected points in time during the simulated mold filling process. The system includes logic for identifying incipient dry spots, and also preferably includes means for interrupting the operation of the program at selected points to vary selected parameters to eliminate incipient dry spots and otherwise maximize the mold filling process.

Abstract: An improved process to make composites contains the steps of: (1) contacting a substrate with a thermoplastic partially-cured curable resin at above the glass-transition temperature to form a preform; (2) adding a matrix resin that can dissolve the tackifier and co-curing the tackifier and matrix resin to form a composite. The resulting composites are useful in structural applications.

Abstract: An improved process to make composites contains the steps of: (1) partially curing a tackifier resin in contact with a substrate to form a shapeable preform; (2) adding a matrix resin and co-curing the tackifier and matrix resin to form a composite. The resulting composites are useful in structural applications.

Abstract: Preforms for molding processes such as resin transfer molding processes are prepared by melting a solid, non-sintering, thermoplastic-like resinous compound on the surface of a substrate material. After cooling, assembling one or more plies of the coated substrate material into the desired shape; heating the shaped substrate material to a temperature above the melting temperature of the resinous compound and subsequently cooling to a temperature below the melting point of the resinous compound.

Abstract: Preforms for molding processes such as resin transfer molding processes are prepared by melting a solid, non-sintering, thermoplastic-like resinous compound on the surface of a substrate material; after cooling, assembling one or more plies of the coated substrate material into the desired shape; heating the thus shaped substrate material to a temperature above the melting temperature of resinous compound and subsequently cooling to a temperature below the melting point of the resinous compound.

Abstract: Damaged composites are repaired by use of a rubber modified vinyl ester resin composition as either an adhesive for bonding metal or cured composite to the area surrounding the damaged area or by placing an uncured reinforcing material saturated with a rubber modified vinyl ester resin composition over the prepared damaged zone and curing in place.

Abstract: A process for producing polyamines such as methylene dianiline wherein an aromatic amine such as aniline is reacted with formaldehyde in the presence of an acid catalyst sufficient water is employed to cause a separation into an aqueous phase and an organic phase and the methylene dianiline is extracted with a solvent said process is improved by employing as the solvent a mixture of aniline and either a water immiscible organic solvent such as orthodichlorobenzene or conducting the extraction in the presence of a water soluble inorganic salt such as zinc nitrate or a combination thereof.

Abstract: An adaptive signal processor including a network that adjusts itself on the basis of power maximization to resolve a raw composite input signal structure at least approximately into its separate statistically independent self-correlated components, or eigenvectors, and automatic gain control circuits for equalizing the power levels, or eigenvalues, of these components. The equalized component signals may be used as inputs to conventional adaptive systems, providing improved settling speed and dynamic range, or may in some cases be used directly, without further adaptive processing.