General Electric Company

Robert David McClain

Seetharamaiah Mannava

William D Cowie

P Kennard Wright, Iii

Brian Michael Davis

Ui Won Suh

Seetha Ramaiah Mannava

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.

Real time laser shock peening quality assurance by natural frequency analysis

A test coupon is formed from a metallic strip having opposite first and second sides that generally define a plane of the strip and the strip includes a laser shock peened patch of the strip that has first and second laser shock peened surfaces on the first and second sides, respectively, first and second laser shocked regions having deep compressive residual stresses imparted by the laser shock peening extending into the strip from the first and second laser shock peened surfaces, respectively, and a deflection of a portion of the strip from a position of the portion before the laser shock peening. The deflection is formed by the laser shock peening such that at least a part and preferably substantially all of the deflection lies in the plane and the test coupon preferably includes an indicating means to indicate the deflection.

In plane deflection coupon for monitoring and controlling of laser shock peening

A method for quality assurance of a laser process and more particularly a laser shock peening process that uses a test coupon having a deflection formed by a laser firing. The test coupon is from a metallic strip having opposite first and second sides that generally define a plane of the strip and the strip includes a laser shock peened patch of the strip that has first and second laser shock peened surfaces on the first and second sides, respectively, first and second laser shocked regions having deep compressive residual stresses imparted by the laser shock peening extending into the strip from the first and second laser shock peened surfaces, respectively, and a deflection of a portion of the strip from a position of the portion before the laser shock peening. The deflection is formed by the laser shock peening such that at least a part and preferably substantially all of the deflection lies in the plane of the strip and the test coupon preferably includes an indicating means to indicate the deflection. The quality assurance process of the present invention may further include correlating high cycle fatigue to the deflection.

Growing community of inventors

Cincinnati, OH, United States of America

Robert David McClain