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.
