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: 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: 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: 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.