Abstract:
A procedure for repairing a polymer matrix composite component is provided. The procedure includes the steps of: providing a polymer matrix composite component having a site prepared for repair by removal of damaged or defective material; locating an uncured, polymer matrix composite repair patch at the site to re-build the component thereat; and curing the polymer matrix of the repair patch by heating the patch using eddy currents induced by one or more alternating current coils. The repair patch is without metallic additives, such that the repaired polymer matrix composite after the curing step is also without metallic additives in the vicinity of the repair patch.
Abstract:
A repair tool for applying a coating patch includes a heating element, a flexible bladder disposed adjacent the heating element, and an inflexible shell disposed about the flexible bladder. The inflexible shell defines a negative space corresponding to a plurality of sides of an aircraft component. A controller is communicatively coupled to the heating element and the bladder, and is configured to control a temperature of the heating element and a pressure of the flexible bladder.
Abstract:
A method of processing a patch includes mounting the patch on a surface of a caul plate having at least one suction hole, and drawing a vacuum through the suction hole to maintain the patch in contact with the caul plate.
Abstract:
A portable curing system includes a carrying case, a controller located within the carrying case and having a microprocessor, a vacuum pump located within the case and having at least two vacuum ports for connection of vacuum lines, at least two vacuum sensor connectors for receiving leads of vacuum sensors, at least two heater connectors for receiving leads of electrical heaters, and at least two temperature sensor connectors for receiving leads of thermocouples. The controller is operably connected to the vacuum pump, the vacuum sensor connectors, the heater connectors, and the temperature sensor connectors. A touch-screen video display is mounted within the carrying case and operably connected to the controller to display information from the controller and input information to the controller. The video display is pivotable between a stowed position and a viewing position.
Abstract:
A method for repairing a high temperature composite structure fabricated from layers of composite plies. If the composite structure contains an internal high temperature core, the core is first restored by installing a core block into the damaged region, bonding the core block in place by applying high temperature material resin and uncured foam material into the region between the core block and the damaged region, and partially curing the core block. A number of repair plies, formed from pre-impregnated composite material or formed using dry cloth manually impregnated with high temperature resin are prepared. The repair plies are sized and shaped using a series of templates corresponding to the damaged region. The installed plies are cured using high temperature localized heating of the damaged region without impairing the surrounding structure.
Abstract:
A method of replicating surface textures by providing a laminar, dimensionally stable, flexible mold having an impression of the surface texture to be formed on one side thereof, applying a layer of fluid casting material to the flexible mold, and partially curing the resinous material wherein the impression is transferred to the partially cured resinous material. The flexible mold and layer of partially cured resinous material are then secured to a recipient surface, and the material is fully cured, and the flexible mold removed, leaving a surface texture on the recipient surface.
Abstract:
Apparatus for applying heat to a patch on a composite structure repair site is disclosed. The apparatus includes a sealed bladder containing both a thermally conductive fluid and a heating element in thermal contact with the fluid. The heating element which comprises a flexible sheet having an electrical resistance wire uniformly placed thereon can be immersed in the fluid or otherwise in direct thermal contact therewith. Electrical power is applied to the heating element by conductors passing through the bladder surface. The heating element of disclosed structure can be attached to seal the bladder interior into two reservoirs, to permit fluid flow throughout the bladder or to form at least one outer surface of the bladder. Flexible supports can also be attached from the heating element to an interior bladder surface to maintain spacing between the heating element and the surface. To prevent diffusion of the thermally conductive fluid, a separate container of thermally conductive fluid impermeable material can be placed inside the bladder. The outer bladder may be sealed by mechanical frame apparatus which compresses the bladder surface material at a perimeter thereof.
Abstract:
A conformal oven which has flexible sidewalls for enabling it to conform to and seal against a contoured surface. A vacuum sealing bag is sealed over a patch on a contoured surface such as an airplane wing made of an epoxy composite material. A vacuum is created within a vacuum sealing bag over the patch and the oven is placed over the patch and is sealed against the contoured surface being patched. A partial vacuum is created within the oven to maintain the seal against the contoured surface. The atmosphere within the oven is heated by force convection of air, electric heating or other alternative heating means to cure the patch within the evacuated vacuum sealing bag.The conformal oven is formed with flexible sidewalls, preferably accordian-like in shape, to enable the open end of the oven to conform to the contoured surface being patched and to enable sealing of the open end of the oven to the contoured surface in order to perform the curing process.
Abstract:
A method for repairing or retreading a vehicle tire comprising the steps of filling a repair region with vulcanisable rubber, covering the repair region with a flexible cover attached around its edges to the tire with an adhesive, piercing the cover with a suction needle at points where air or other gases have accumulated, sealing of the openings made by the needle, and heating the repair region to vulcanize the repair rubber.
Abstract:
A portable repair apparatus having a pair of chambers separated by a flexible diaphragm having a heating element therein. One chamber has a connection to an evacuating means while the other chamber is connected to a pressure source. After mounting the repair apparatus over a patch on the damaged area of a surface, the creation of a vacuum in one chamber and the increase in pressure in the other chamber causes the flexible diaphragm to apply sufficient pressure to the patch in order to bond it to the damaged surface.