Abstract: A method for laser shock peening an article includes laser shock peening the article forming at least one pre-stressed region having deep compressive residual stresses imparted by the laser shock peening and machining a feature into article in the pre-stressed region after the laser shock peening. The feature may be machined entirely in the pre-stressed region. The pre-stressed region may extend completely between oppositely spaced apart sides of the article with the feature machined entirely through the pre-stressed region and completely between and through the spaced apart outer and inner sides. The feature may be a hole or a scallop. The article may be an arcuate wall having a radius of curvature and the feature includes a centerline and is machined into wall with the centerline substantially parallel to the radius of curvature. The hole or scallop may have a curved sharp edge.

Abstract: A real time method for quality control testing of a laser shock peening process of production workpieces by analysis of natural frequency shifts during the laser shock peening process. One particular embodiment includes laser shock peening surface of the production workpiece by firing a plurality of laser beam pulses on the surface and forming a plurality of corresponding plasmas, each one of the plasmas pulses having a duration in which the plasma causes a region having deep compressive residual stresses to form beneath the surface, measuring at least one natural frequency of the workpiece for each of the laser beam pulses, calculating natural frequency shifts from a baseline natural frequency for the measured natural frequencies for at least a portion of the laser beam pulses, and using the natural frequency shifts for accepting or rejecting the workpiece with respect to pass or fail criteria.

Abstract: A real time method for quality control testing of a laser shock peening process of production workpieces by analysis of natural frequency shifts during the laser shock peening process. One particular embodiment includes laser shock peening surface of the production workpiece by firing a plurality of laser beam pulses on the surface and forming a plurality of corresponding plasmas, each one of the plasmas pulses having a duration in which the plasma causes a region having deep compressive residual stresses to form beneath the surface, measuring at least one natural frequency of the workpiece for each of the laser beam pulses, calculating natural frequency shifts from a baseline natural frequency for the measured natural frequencies for at least a portion of the laser beam pulses, and using the natural frequency shifts for accepting or rejecting the workpiece with respect to pass or fail criteria.