Abstract: A method and apparatus for quality control of laser shock processing. The method includes measuring emissions and characteristics of a workpiece when subjected to a pulse of coherent energy from a laser. These empirically measured emissions and characteristics of the workpiece are correlated to theoretical shock pressure, residual stress profile, or fatigue life of the workpiece. The apparatus may include a radiometer or acoustic detection device for measuring these characteristics.

Abstract: A method is disclosed for repairing damage to an airfoil. The method provides for the removal of a section of the airfoil that substantially encompasses the damaged area, which consequently leaves a void and a cut-away surface in the airfoil. A replacement piece larger than the residual void is provided for use in replacing the section removed from the airfoil. A joining operation welds or otherwise joins the replacement piece to the airfoil at the cut-away surface to form a joined airfoil. The joined airfoil has a seam between the airfoil and the replacement piece. At least a portion of the seam is processed by laser shock peening to induce compressive residual stresses therein.

Abstract: The invention relates to a method and apparatus for improving properties of a solid material by providing shockwaves therethrough. The method includes controlling the incident angle &THgr; of the laser beam applied to the workpiece so that the required residual stresses are created in the workpiece. Particular methods of control such as lenses, polarizers, and particular transparent overlay geometries are shown. The apparatus includes structure for controlling the position and incident angle of the laser beam then controlling the polarization and/or the shape of the incident impact area, based on such incident angle &THgr; or thickness of the workpiece.

Abstract: A method of altering the properties of a solid material by varying the temperature of the solid material either before or after or both before and after laser shock processing the solid material. In addition, the method may be repeated for successive laser shock processing of the solid material.

Abstract: A laser shock processing apparatus with controller for controlling laser shock processing operation. The controller generates an operator perceivable alert when a processing value is not within a predetermined range of a preset value. The controller may adjust the processing value to be within the predetermined range or may deactivate a laser from directing a beam of coherent energy to a workpiece. In one embodiment, a plurality of controllers comprise distributed processing of various processing values for controlling laser shock processing operation.

Abstract: A method of laser shock peening a workpiece including the steps of laser shock peening at least one surface of the workpiece so that it extends over an area of the workpiece and forms a region having compressive residual stresses imparted by the laser shock peening extending into the workpiece from the surface, and firing a laser beam to produce the laser shock peened surface with more than one row of laser beam spots, wherein adjacent laser beam spots and/or rows are one of touching or spaced apart from each other.

Abstract: An apparatus creating a processing cell for laser peening operations includes an enclosure which substantially defines a work cell or processing cell with a transparent overlay material applicator disposed therein. A cleaning system is utilized that may include a vapor exhaust, liquid removal system, and a gas or air supply. A vapor exhaust system is connected to the enclosure for removing vapor from within the processing cell. A liquid removal system is connected to the enclosure for removing liquid from the processing cell. A gas or air supply is connected to the enclosure to flood the enclosure with gas or air to flush airborne debris therefrom. A workpiece manipulator may be disposed or operate within the cell for moving workpieces therein.

Abstract: A hollow workpiece includes an outside surface through which a port opens to the hollow interior, and a laser peened area on the surface of the workpiece. The laser peened area is created on the surface while the hollow interior is at least partially filled with a substance other than air. A method of laser peening a hollow core gas turbine engine blade includes the steps of providing a hollow core gas turbine engine blade, filling the hollow core with a substance other than air, and then, laser peening the hollow core gas turbine engine blade.

Abstract: An apparatus creating a processing cell for laser peening operations includes an enclosure which substantially defines a work cell or processing cell with a transparent overlay material applicator located therein. A cleaning system is utilized that may include a vapor exhaust, liquid removal system, and a gas or air supply. A vapor exhaust system is connected to the enclosure for removing vapor from within the processing cell. A liquid removal system is connected to the enclosure for removing liquid from the processing cell. A gas or air supply is connected to the enclosure to flood the enclosure with gas or air to flush airborne debris therefrom. A workpiece manipulator may be disposed or operate within the cell for moving workpieces therein.

Abstract: The present invention provides a method of laser shock processing that can be used in a production environment that increases the peak pressure of the shock wave applied to the workpiece that increases residual compresses stresses therein. Such improvement is created by a reduction of dielectric breakdown of the transparent overlay layer utilized.The method includes the steps of applying a transparent overlay such as water over the workpiece and reducing or limiting the thickness of the transparent overlay material. An alternate embodiment of the invention to reduce dielectric breakdown incorporates the use of a changing or circularly polarized laser beam as opposed to a linearly polarized laser beam.

Abstract: A method and apparatus for improving properties of a solid material by providing shock waves therethrough. Laser shock processing is used to provide the shock waves. The method includes applying a transparent overlay to the solid material to be worked. The solid material or overlay is vibrated to release any gas bubbles or solid debris within the transparent layer which could cause localized non-uniform confinement of a pressure pulse applied for a workpiece thereby causing irregularities in the workpiece surface. A pulse of coherent laser energy is the directed to the coated portion of the solid material to create a shock wave. Additionally, the method may include adding a wetting agent or controlling the temperature of the overlay material to reduce the concentration of gas bubbles therein.

Abstract: The invention includes a laser processing method for processing a hidden surface of a workpiece, the hidden surface disposed within a recess having an opening. The method comprises inserting a reflective member into the recess and directing a pulse of coherent energy to reflect off of said reflective member and impact the hidden surface of workpiece to create a shock wave. Alteratively a surface of the recess may be modified to laser shock process the hidden surface.

Abstract: A method of modifying the vibration resonance characteristics of a workpiece includes the steps of determining a vibratory resonance condition frequency of the workpiece, determining the mode shape of said vibratory resonance condition, locating an area on the workpiece that includes a maximum curvature for the determined mode shape and vibratory resonance condition frequency; then laser shock peening the located area to create residual compressive stresses within the workpiece to shift the determined vibratory resonance condition frequency. A workpiece such as a gas turbine engine blade is also disclosed.

Abstract: A laser peening apparatus, including a laser generator to generate a laser beam having a first cross-sectional shape; and a diffractive optic element. The diffractive optic element changes the laser beam to a second cross-sectional shape. The apparatus also includes demagnifying and magnifying lenses. The diffractive optic element may create a second cross-sectional shape such as rectangular, hexagonal, or even split the laser beam into multiple beams. The diffractive optic element may also create a second cross-sectional shape of the laser beam varying in intensity thereacross or varying in energy distribution.

Abstract: Method of changing the residual compressive stresses of an area of a workpiece by tailoring multiple laser beams applied to the workpiece. In one embodiment, a relatively long duration laser pulse is applied to the workpiece followed by a relatively short duration laser pulse. Other tailoring embodiments used to increase the total residual compressive stress of workpieces include blending two laser pulses, or splicing them utilizing a first short sliced-type beam combined with a relatively long duration, high powered gaussian laser beam pulse. A third embodiment utilizes two or more laser beams or pulses of different wavelengths.

Abstract: A method and apparatus for improving properties of a solid material by providing shockwaves therethrough. The method includes controlling the incident angle .theta. of the laser beam applied to the workpiece so that the required residual stresses are created in the workpiece. Particular methods of control such as lenses, polarizers, and particular transparent overlay geometries are shown. The apparatus includes structure for controlling the position and incident angle of the laser beam then controlling the polarization and/or the shape of the incident impact area, based on such incident angle .theta..

Abstract: The invention relates to a method and apparatus for improving properties of a solid material by providing shock waves therethrough. Laser shock processing is used to provide the shock waves. The method includes applying a water based coating to a portion of the surface of the solid material and then applying a transparent overlay to the coated portion of the solid material. A pulse of coherent laser energy is directed to the coated portion of the solid material to create a shock wave. A high speed jet of fluid is directed to coated portion of the solid material at times to remove the coating from the solid material. Additionally, the method may include directing a high speed jet of fluid to the surface of the solid material to dry the solid material.