Abstract: A system for neutralizing a buried mine includes a laser that is configured to generate laser energy that communicates through the covering ground material and accesses the mine in a manner sufficient to neutralize the mine. Neutralization can occur by deflagration or detonation. The laser includes a solid-state lasing medium that is run substantially uncooled during the lasing run. Namely, the lasing medium is operated without cooling until the lasing medium reaches a temperature where thermal population in a lower laser level begins to significantly lower inversion density. Following completion of the lasing run, the lasing medium is cooled at a rate limited only by a thermal stress fracture level of the lasing medium. Operation of the laser in this manner permits the laser to deliver high-irradiance, high-repetition rate pulses according to a burst mode operation that successfully accomplishes neutralization in a desired time period.

Abstract: Various laser shock processing systems are provided to establish selective compressive residual stress distribution profiles within a workpiece. An asymmetrical stress profile may be formed through the thickness of a thin section of a gas turbine engine airfoil. One system is configured to simultaneously irradiate a workpiece with a set of laser beams to form a corresponding set of adjacent non-overlapping laser shock peened surfaces, enabling the shockwaves to encounter one another. Another system irradiates opposite sides of the workpiece at different times to form opposing laser shock peened surfaces, enabling the shockwaves to meet at a location apart from the mid-plane. Another system simultaneously irradiates opposite sides of the workpiece using laser beams having different pulse lengths to form opposing laser shock peened surfaces. Another system simultaneously irradiates opposite sides of the workpiece to form a set of laterally offset laser shock peened surfaces.

Abstract: Articles produced by laser shock processing exhibit various compressive residual stress distribution profiles. A gas turbine engine airfoil includes an asymmetrical stress profile formed through the thickness of its thin section. The articles include plural laser shock peened surfaces and plural regions having deep compressive residual stresses imparted by laser shock peening extending into the article from the laser peened surfaces. One article includes at least one set of simultaneously formed, adjacent non-overlapping laser shock peened surfaces. Another article includes at least one set of opposing laser shock peened surfaces formed at different times at opposite sides of the article. Another article includes at least one set of opposing laser shock peened surfaces formed simultaneously at opposite sides of the article using laser beams having different pulse lengths.

Abstract: A method and apparatus for increasing the effectiveness and efficiency of laser shock processing of a solid material. The method includes applying an energy absorbing coating to a portion of the surface of a solid material, applying an ultraviolet curable resin to the coated portion of the surface of the solid material, applying an ultraviolet light to the curable resin to form a pellicle over the energy absorbing coating on the surface of the solid material, and applying a transparent overlay to the pellicular portion of the solid material. A pulse of coherent laser energy is directed to the coated portion of the solid material to create a shockwave. After the pulse of coherent energy is directed to the solid material, a high-speed jet of fluid may be directed to the coated portion of the solid material to remove the remaining coating from the solid material.

Abstract: A method and apparatus for increasing the effectiveness and efficiency of laser shock processing of a solid material. The method includes applying an energy absorbing coating to a portion of the surface of a solid material, applying an ultraviolet curable resin to the coated portion of the surface of the solid material, applying an ultraviolet light to the curable resin to form a pellicle over the energy absorbing coating on the surface of the solid material, and applying a transparent overlay to the pellicular portion of the solid material. A pulse of coherent laser energy is directed to the coated portion of the solid material to create a shockwave. After the pulse of coherent energy is directed to the solid material, a high-speed jet of fluid may be directed to the coated portion of the solid material to remove the remaining coating from the solid material.

Abstract: Various laser shock processing methods are provided to establish selective compressive residual stress distribution profiles within a workpiece. An asymmetrical stress distribution profile may be formed through the thickness of a thin section of a gas turbine engine airfoil. One method involves simultaneously irradiating a workpiece with a set of laser beams to form a corresponding set of adjacent non-overlapping laser shock peened surfaces, enabling the shockwaves to encounter one another. Additionally, opposite sides of the workpiece may be irradiated at different times to form opposing laser shock peened surfaces, enabling the shockwaves to meet at a location apart from the midplane. Furthermore, opposite sides of the workpiece may be irradiated simultaneously using laser beams having different pulse lengths to form opposing laser shock peened surfaces. Moreover, opposite sides of the workpiece may be irradiated simultaneously to form a set of laterally offset laser shock peened surfaces.

Abstract: The present invention enables the processing head to locate itself precisely on the surface of the structure being processed, and to then reposition itself correctly for the next laser spot. Further, the present invention will complete processing a laser peened area, the area including a multiplicity of spots arranged in a specific pattern, and correctly laser peen each spot in the area under control of a controller including control linkages with the laser.

Abstract: A method of controlling the application of laser peening overlays on the surface of a workpiece to reduce the variability of shock waves generated therein, comprises applying an energy-absorbing overlay to a portion of the surface of a workpiece, measuring the thickness of the energy-absorbing overlay in at least one location on the energy-absorbing overlay, applying a transparent overlay material over the energy-absorbing overlay, measuring the thickness of the transparent overlay in at least one location on the transparent overlay, determining if the measured values for each overlay is within a specified range, and directing a pulse of coherent energy to the workpiece to create a shock wave therein when the measured values are within the specified range.

Abstract: The invention, in another form thereof, comprises a method of laser shock peening the surface of a solid material with or without the use of a transparent overlay material. An energy absorbing coating is applied to a portion of the surface of a solid material. An ultraviolet-curable resin coating is applied to the energy absorbing coating and the curable resin is exposed to an ultraviolet light and forms a pellicle over the energy absorbing coating. A pulse of coherent energy is directed to the energy absorbing coating of the solid material to create a shock wave.

Abstract: A method of controlling the application of laser peening overlays on the surface of a workpiece to reduce the variability of shock waves generated therein, comprises applying an energy-absorbing overlay to a portion of the surface of a workpiece, measuring the thickness of the energy-absorbing overlay in at least one location on the energy-absorbing overlay, applying a transparent overlay material over the energy-absorbing overlay, measuring the thickness of the transparent overlay in at least one location on the transparent overlay, determining if the measured values for each overlay is within a specified range, and directing a pulse of coherent energy to the workpiece to create a shock wave therein when the measured values are within the specified range.

Abstract: An exfoliation corrosion detection method which enables rapid detection and evaluation of hidden exfoliation corrosion on aircraft with related cost savings. Pressure exerted on the surface by the laser created plasma generates a pressure pulse or shock wave that propagates into the part. When the stress in the shock wave is above the dynamic elastic limit of the material, the surface material yields plastically. This plastic strain creates compressive residual stresses in the surface, thereby enabling detection of exfoliation corrosion, if present.

Abstract: A method of controlling the application of laser peening overlays on the surface of a workpiece to reduce the variability of shock waves generated therein, comprises applying an energy-absorbing overlay to a portion of the surface of a workpiece, measuring the thickness of the energy-absorbing overlay in at least one location on the energy-absorbing overlay, applying a transparent overlay material over the energy-absorbing overlay, measuring the thickness of the transparent overlay in at least one location on the transparent overlay, determining if the measured values for each overlay is within a specified range, and directing a pulse of coherent energy to the workpiece to create a shock wave therein when the measured values are within the specified range.

Abstract: Articles produced by laser shock processing exhibit various compressive residual stress distribution profiles. A gas turbine engine airfoil includes an asymmetrical stress profile formed through the thickness of its thin section. The articles include plural laser shock peened surfaces and plural regions having deep compressive residual stresses imparted by laser shock peening extending into the article from the laser peened surfaces. One article includes at least one set of simultaneously formed, adjacent non-overlapping laser shock peened surfaces. Another article includes at least one set of opposing laser shock peened surfaces formed at different times at opposite sides of the article. Another article includes at least one set of opposing laser shock peened surfaces formed simultaneously at opposite sides of the article using laser beams having different pulse lengths.

Abstract: Various laser shock processing methods are provided to establish selective compressive residual stress distribution profiles within a workpiece. An asymmetrical stress distribution profile may be formed through the thickness of a thin section of a gas turbine engine airfoil. One method involves simultaneously irradiating a workpiece with a set of laser beams to form a corresponding set of adjacent non-overlapping laser shock peened surfaces, enabling the shockwaves to encounter one another. Additionally, opposite sides of the workpiece may be irradiated at different times to form opposing laser shock peened surfaces, enabling the shockwaves to meet at a location apart from the midplane. Furthermore, opposite sides of the workpiece may be irradiated simultaneously using laser beams having different pulse lengths to form opposing laser shock peened surfaces. Moreover, opposite sides of the workpiece may be irradiated simultaneously to form a set of laterally offset laser shock peened surfaces.

Abstract: Various laser shock processing systems are provided to establish selective compressive residual stress distribution profiles within a workpiece. An asymmetrical stress profile may be formed through the thickness of a thin section of a gas turbine engine airfoil. One system is configured to simultaneously irradiate a workpiece with a set of laser beams to form a corresponding set of adjacent non-overlapping laser shock peened surfaces, enabling the shockwaves to encounter one another. Another system irradiates opposite sides of the workpiece at different times to form opposing laser shock peened surfaces, enabling the shockwaves to meet at a location apart from the mid-plane. Another system simultaneously irradiates opposite sides of the workpiece using laser beams having different pulse lengths to form opposing laser shock peened surfaces. Another system simultaneously irradiates opposite sides of the workpiece to form a set of laterally offset laser shock peened surfaces.

Abstract: A method and apparatus for increasing the effectiveness and efficiency of laser shock processing of a solid material. The method includes applying an energy absorbing coating to a portion of the surface of a solid material, applying an ultraviolet curable resin to the coated portion of the surface of the solid material, applying an ultraviolet light to the curable resin to form a pellicle over the energy absorbing coating on the surface of the solid material, and applying a transparent overlay to the pellicular 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. After the pulse of coherent energy is directed to the solid material, a high-speed jet of fluid may be directed to the coated portion of the solid material to remove the remaining coating from the solid material.

Abstract: A multiple laser peening cell apparatus for receiving pulses of energy from a laser shock peening device is comprised of a first cell for receiving a first pulse of energy, a second cell for receiving a second pulse of energy, and a beam distribution means, for directing the first pulse of energy and the second pulse of energy. Also, a method of directing pulses of energy originating from a single source to multiple workpieces comprises the steps of creating a first pulse of energy, directing the first pulse of energy to a first workpiece located in a first laser peening cell, creating a second pulse of energy, and directing the second pulse of energy to a second workpiece located in a second laser peening cell.

Abstract: A method of producing a workpiece involves positioning the workpiece at a current processing position indicated by a hard-coded part program and then collecting position data which defines the positional arrangement of a current target area of the workpiece. The collected position data is processed by comparing it to reference position information that represents the positional arrangement of the same target area in an ideal workpiece employed in the development of the part program. The position of the workpiece (and hence the target area) is adjusted in accordance with the comparison results. A laser shock processing operation is performed on the workpiece at the current target area following the position adjustment step.

Abstract: A method and apparatus for measuring the quality of a laser peening process, which includes a test element, a mount for the test element, wherein the test element is mounted at a preselected point in the anticipated path of a laser pulse, the laser pulse irradiates the test element, the deflection of the test element is measured in the direction substantially perpendicular and away from the impacted surface of the test element, and the deflection measurement is compared to a previously generated chart showing the relationship between characteristics of test elements and desired material properties.

Abstract: 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.