Abstract: A crack weld repair and method, particularly, for a gas turbine engine blade or other metallic component in the engine, providing a metallic substrate, a metallic filler bonded onto a substrate bond surface on the metallic substrate, and a region having deep compressive residual stresses imparted by laser shock peening extending into the substrate beneath the substrate bond surface. One embodiment provides a laser shock peened surface below the weld material filled void in a damaged area of the component forming a region of deep compressive residual stresses imparted by laser shock peening (LSP) extending from the laser shock peened surface into the component. Optionally, the surface over the repaired area of the weld filled void may also be laser shock peened forming a second region of deep compressive residual stresses imparted by laser shock peening (LSP) extending from the laser shock peened surface into the weld repair.

Abstract: A damper which, in one form, includes a damper ring having inner and outer radial surfaces, axial retainers extending radially outward from the outer radial surface, and an annular stiffener protruding radially inward from the inner radial surface, is described. The axial retainers prevent disengagement of the damper ring from the structural member. The stiffener adds mass to the damper ring such that the radial distance of the neutral axis of the damper ring from the neutral axis of the structural member is increased, thus increasing damping effectiveness. The stiffener also adds torsional and bending rigidity to the damper ring so that the damper ring is further prevented from disengaging from the structural member.

Abstract: A system for cooling hot section components of a gas turbine engine. The cooling system includes a plurality of compressors, or compression train, and an intercooler disposed between each adjacent pair of compressors so as to achieve the desired pressure and temperature of the cooling air at reduced shaft power requirements. The first stage of compression may be provided by the booster, or low pressure compressor, of the engine, with the first intercooler receiving all of the air discharging from the booster. After exiting the first intercooler, a first portion of the booster discharge air is routed to the engine high pressure compressor and a second portion is routed to an inlet of the second compressor of the cooling air compression train. The compressed, cooled air exiting the last, downstream one of the compressors is used for cooling at least a first hot section component of the engine.

Abstract: An aircraft turboshaft engine intake includes an axial diffuser and a colinear plenum disposed in flow communication therewith for collecting diffuser air therefrom. A scroll is disposed radially below the plenum in flow communication therewith for accelerating the plenum air for discharge to the aircraft engine. In this arrangement, propeller air is diffused in the diffuser and collected in the plenum wherein it is turned radially inwardly and accelerated through the scroll into the engine. Diffusion is uncoupled from air turning for improving the efficiency thereof.

Abstract: In a computed tomography imaging system, wherein a longitudinally-unbounded object is oriented with respect to a source of cone beam radiation and a detector array, a method is provided for reconstructing an image of the longitudinally-unbounded object. Initially, relative movement between a longitudinally-unbounded object and the cone beam source is established along at least one circular scan path and at least one linear component. The cone beam is operated to irradiate measurable regions of the object while a prescribed orbit is traversed, to project an image of the longitudinally-unbounded object as cone beam data, onto the detector array. A scan field of view is defined, relative to the cone beam geometry. An error propagation distance in a Z direction is determined for the scan. The definition of the scan field of view is then modified, according to error propagation distance, and a set of image reconstruction data is generated, within the modified field of view, from the circular and linear scan paths.

Abstract: A method and apparatus for forming a passage with a variable diameter along its length in a conductive workpiece are disclosed. The workpiece is mounted in a fixture and an externally insulated hollow electrode is positioned proximate to a surface location of the workpiece into which the passage is to be formed. A first selected voltage is connected between the electrode and the workplace with the voltage being connected to cause the electrode to act as a cathode and the workpiece to act as an anode. A pump causes an acidic electrolyte to flow through the electrode at a chosen pressure and onto the workpiece surface. The electrode is moved toward the workpiece at a first selected feed rate by a CNC controller to cause a portion of the passage to be formed at a first predetermined diameter.

Abstract: A method is provided for locking jet engine exhaust nozzle position in a hydraulic system having nozzle actuators connected by a synchronization cable. The synchronization cable engages with a conical brake locking mechanism to prevent cable rotation in the event of a hydraulic failure. The nozzle is locked in position at the time of the hydraulic failure. This prevents a significant decrease in usable thrust.

Abstract: A gas turbine engine component includes a wall portion with at least one compound cooling hole formed therein between an external surface of the component and an interior plenum. The at least one compound cooling hole includes a non-circular diffuser opening formed by a laser beam with a non-circular cross-sectional area, and a channel with a substantially circular cross-section connecting the diffuser opening and the interior plenum. The channel is also formed by the non-circular laser beam in the same laser drilling operation as the diffuser opening. The cooling hole further includes a transition point at which the compound hole begins to convert from a substantially non-circular cross-section to a substantially circular cross-section. The location of the transition point is controlled by positioning a focal point of the non-circular laser beam to undershoot the external surface of the component by a predetermined distance.

Abstract: A dampening apparatus for dampening vibrations of a workpiece during machining, the dampening apparatus having a dampener, a support to support and place the dampener in abutting vibration absorbing contact with the workpiece, and a dampener fixture for holding the dampener fixed relative to the workpiece. A pressure adjusting apparatus to adjust contact pressure between the dampener and the workpiece is preferably included. The dampener may further include a number of dampening rods supported by the plate at first ends of the rods and which in turn support dampening elements at distal second ends of the rods. The dampening elements may be lugs made of a resilient material such as rubber and the lugs may have flat surfaces for being placed in abutting vibration absorbing contact with the workpiece. The invention also includes a method of machining a thin web of a workpiece having an annular inner hub connected to a concentric annular outer rim by the thin web using the dampener.

Abstract: A thermal barrier coating is provided which is adapted to be formed on an article subjected to a hostile thermal environment while subjected to thermally, mechanically and/or dynamically-induced stresses, such as a component of a gas turbine engine. The thermal barrier coating is composed of a bond layer that tenaciously adheres an insulative ceramic layer to the article. The bond layer is formed of a metallic oxidation-resistant material, and has an average surface roughness R.sub.a of at least about 7.5 micrometers, while the ceramic layer is characterized by being segmented by at least two sets of grooves. The grooves have substantially uniform widths of about 100 to about 500 micrometers, with adjacent grooves of each set being spaced about 10 to about 250 millimeters apart.

Abstract: A wide gap braze repair, particularly for a gas turbine engine vane or a component in the hot section of the engine. The repair is characterized by a braze filled void in a damaged area of the component, a laser shock peened surface over the repaired area of the braze filled void, and a region of deep compressive residual stresses imparted by laser shock peening (LSP) extending from the laser shock peened surface into the repair.

Abstract: A method of laser shock peening a metallic part by firing a laser on a laser shock peening surface of the part which has been adhesively covered by tape having an ablative medium, preferably, a self adhering tape with an adhesive layer on one side of an ablative layer and a confinement medium without flowing a confinement curtain of fluid over the surface upon which the laser beam is firing. Continuous movement is provided between the part and the laser beam while continuously firing the laser beam, which repeatably pulses between relatively constant periods, on a laser shock peening surface of the part. Using a laser beam with sufficient power to vaporize the ablative medium so that the pulses form laser beam spots on the surface and a region having deep compressive residual stresses imparted by the laser shock peening process extending into the part from the surface.

Abstract: A method of laser shock peening a metallic part by firing a laser on a laser shock peening surface of the part which has been adhesively covered by tape having an ablative medium, preferably a self adhering tape with an adhesive layer on one side of an ablative layer, while flowing a curtain of water over the surface upon which the laser beam is firing. Continuous movement is provided between the part and the laser beam while continuously firing the laser beam, which repeatably pulses between relatively constant periods, on a laser shock peening surface of the part. Using a laser beam with sufficient power to vaporize the ablative medium so that the pulses form laser beam spots on the surface and a region having deep compressive residual stresses imparted by the laser shock peening process extending into the part from the surface.

Abstract: A die having a metallic block with a depression, the depression having at least one cross-sectional transition zone, at least one laser shock peened surface encompassing at least a portion of the zone, a region having deep compressive residual stresses imparted by laser shock peening (LSP) extending into the airfoil from the laser shock peened surface. The die has been found to be useful for cold rolling blanks such when the metallic block is a cold rolling die block. The die may be adapted for forming a gas turbine engine component, such as a compressor blade, having an airfoil such that the depression corresponds to the airfoil.

Abstract: A method for preparing a Ni base superalloy inner wall surface of a body open end, such as an end of a turbomachinery blade, and an end plate, such as a blade tip cap, for brazing together at a rim of the end plate includes electrochemically removing oxides from the inner wall surface. The end plate is prepared, at least at its rim, by first removing surface and subsurface oxides, for example by mechanical abrading or a combination of such abrading and acid cleaning. Then at least the rim is electroplated with Ni which is heated to diffuse the Ni into the rim substrate. This provides an improved combination of surfaces for brazing for example with a Ni base brazing alloy. After brazing the rim to the inner wall, there is provided an article with an improved relatively low oxide brazed joint, including less than about 20 volume % oxides, and a plate rim of substantially Ni along with elements diffused from the brazing alloy and the rim.

Abstract: Gas turbine engine blade with a metallic airfoil having a radially outer tip extending chordwise between a leading edge and a trailing edge and at least one laser shock peened surface extending radially along at least a portion of the tip and a region having deep compressive residual stresses imparted by laser shock peening (LSP) extending into the airfoil from the laser shock peened surface.

Abstract: A process is provided for removing a thermal barrier coating that has been deposited on the surface of an article. Thermal barrier coatings that can be removed by the process of this invention are generally composed of a ceramic layer that is bonded to the surface of an article by a metallic bond layer. The process generally involves heating the article and its thermal barrier coating to a temperature of at least about 870.degree. C., and exposing the thermal barrier coating to a halogen-containing agent for a duration sufficient to deteriorate the bond between the thermal barrier coating and the article to the extent that the coating separates from the article without damaging the underlying surface. The process can be carried out within various types of heated enclosures, including those within which the halogen-containing agent is introduced in a gaseous state, or those in which the halogen-containing agent can be prepared as a powder mixture that changes to a vapor when heated.

Abstract: A ball joint includes a tubular outer shroud having a unique one-piece weld-free socket which receives a complementary ball of a tubular inner shroud. The ball joint is preferably formed by plastically deforming the outer shroud to integrally form the socket around the ball. The socket may be formed around a preformed ball, or both the ball and socket may be integrally plastically formed simultaneously.

Abstract: A grinding wheel is provided having a wheel body and an abrasive surface layer having a plurality of dead end grooves extending rearwardly from the side of the circumference of the wheel to effectively gather and then trap coolant therein during grinding. The dead end grooves are preferably arranged in alternating right and left hand sections extending respectively from the right and left hand sides of the wheel. The dead end grooves effectively feed and trap coolant therein during cutting. The grinding wheel and related grinding method effectively reduce workpiece burning during creep feed grinding large surface areas and deep cuts, with a water base coolant.

Abstract: A method for forming an aperture in a component wall made of metal, the aperture having a diffuser which opens up and outward from a bottom of the diffuser to a first surface of the wall, the method includes the following steps: A) laser machining the wall with a laser which produces a laser beam having a pulse rate and power sufficient to vaporize the metal; B) firing and traversing the laser beam, preferably at an acute angle, across the surface to a predetermined first edge of the diffuser in a single pass starting at a centerline of the diffuser; and C) traversing the laser beam at an increasing rate of speed during the pass so that each beam pulse vaporizes the metal at a laser spot such that successive laser spots substantially overlap each other in decreasing amounts and the pulses nibble out the metal to form a continuous trench below the surface.