Remarks on Residual Stress Measurement by Hole-Drilling and Electronic Speckle Pattern Interferometry

Table 2

Values of the measured average stress obtained by keeping constant 𝑅_ext = 2.62 mm and by changing 𝑅_int. The expected theoretical value was 𝜎_𝑥𝑥 = 138 MPa. Also standard deviations are reported as a result of three different drilled holes.

	𝑅int = 1.11 mm	𝑅int = 1.27 mm	𝑅int = 1.43 mm	𝑅int = 1.59 mm
𝜎𝑥𝑥 [MPa]	108.2	129.1	135.5	138.6
Δ𝜎𝑥𝑥 (%)	21.6	6.4	1.8	0.4