RESIDUAL STRESS MEASUREMENT USING THE HOLE DRILLING METHOD AND LASER SPECKLE INTERFEROMETRY PART III: ANALYSIS TECHNIQUE

• Published in: Experimental techniques (Westport, Conn.) Vol. 27; no. 5; pp. 45 - 48
• Main Authors: Ponslet, E., Steinzig, M.
• Format: Journal Article Magazine Article
• Language: English
• Published: Oxford, UK Blackwell Publishing Ltd 01.09.2003; Springer Nature B.V
• ISSN: 0732-8818; 1747-1567
• DOI: 10.1111/j.1747-1567.2003.tb00130.x

Parts I and II of this series described how an electronic speckle pattern interferometer (ESPI) could be configured to measure residual stress using the hole drilling method. Drilling a small hole in a part locally relieves residual stress, and the resulting deformation (or strain) is measured. Part I described the layout of the hardware, and Part II described a full-field least squares analysis for reducing the deformation data to residual stress results. In this section, we will describe som eof the assumpitons that have been made in the anslysis, and how these assumptions can affect the accuracy of the measurements. Many of these assumptions apply not only to the ESPI technique, but also to the traditional strain gage hole drilling method of measuring residual stress, or in some cases to any type of method that is based on relieving the stresses and measuring the resulting deformation. After describing the assumptions and the potential effect on results, we have listed potential errors in the ESPI hole drilling technique, and quantified as many as possible.