Abstract: An apparatus and method for providing a substantially debris-free laser beam path for use during laser shock processing. The method and apparatus include a system for removing debris from the laser beam path and a system for preventing debris from entering the laser beam path.

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 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: An apparatus for measuring the strength of a pressure pulse created from a laser peening device. The apparatus is reusable, and includes a pressure-sensitive medium, a back-up disk, and a cap, all disposed within a housing having a removable lid. All components of the apparatus are replaceable, thereby allowing an operator to utilize the apparatus more than once despite the harsh environment of laser peening.

Abstract: An image processing system for monitoring a laser peening process includes a laser peening system having a workpiece positioner and a system controller. A video camera is utilized for forming an electronic image of at least a portion of a workpiece. An image processing computer is connected to the video camera, and the laser peening controller includes a program to determine a position of the workpiece.

Abstract: A remote laser shock processing system for improving the properties of a solid workpiece by providing shock waves therein. The system includes a remote output end and a laser beam delivery arrangement for directing a beam of coherent energy to a specific location along a workpiece. In addition, a method of utilizing the remote laser shock processing system is included.

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 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: 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..