Residual Stress Measurement by ESPI Hole Drilling and XRD – A Comparison of the Methods Using Measurements on Shot-Peened Titanium Alloys

Author:  T.J. Rickert and L. Suominen
Source:  ICSP-13
Doc ID:  2017044
Year of Publication:  2017
Abstract:  
Introduction: A full assessment of the residual stress state in a shot-peened part requires measuring a residual stress depth profile. The most common methods for stress measurements are X-ray diffraction (XRD) and hole drilling. Such measurements may be used for testing and fine tuning of the shot peening process or for verifying the stress state in specific or representative parts. The XRD technique is highly regarded, but doesn’t work equally well in all materials and can be slow. The traditional hole drilling technique requires the proper attachment of strain gages, which requires expertise and extra time. A newer variation of the technique combines hole drilling with an optical measurement, Electronic Speckle Pattern Interferometry (ESPI). This reduces the setup time substantially while maintaining fast measurement times.