108 C. Pappalettere cross slitting and dual-axis ESPI were introduced demonstrating that this configuration gives better results with respect to the determination of the shear stress profile. In [64] an hybrid approach combining hole-drilling and ring-core techniques was studied. Most recent works are devoted to the improvement of calculation methods; in [65] the integral method for stress calculation in incremental hole drilling was modified so that the speckle image recorded at each drill increment is not correlated with the initial reference state but with the image obtained at the previous step. The matrix that rules the problem in such a case connecting incremental strain to stresses turns out to be diagonally dominant so that all the system is better conditioned and error amplification is reduced. 17.5 Final Considerations Literature review clearly displays how the use of ESPI in combination with hole-drilling method has greatly developed along the years. Technological evolution in terms of smaller, cheaper and higher resolution CCD camera as well as smaller and higher quality laser sources allows now to obtain very robust and compact setup that can also be used outside the laboratory [66–67]. At the same time calculation algorithm have been refined along the years and a series of tools have been introduced so that fringe analysis can be considered to be a semi-automated process that can be quite easily managed also by a trained but not expert operator even in industrial environment as it happens for different approaches [68, 69]. Due to these considerations technology appears to be mature as it is also witnessed by the presence of commercial systems available on the market and based upon this approach. It is easy to foresee that this kind of approach will be subjected to further development and spread. At the same way it can be speculated that new research will be done on the topic in the next years for example in the direction to extend its application to non-isotropic materials or in the direction to compare this approach with a more recent one based upon detection of displacement fields by Digital Image correlation [70–73]. References 1. Lee, K.T., Park, C.S., Kim, H.Y.: Fatigue and buckling analysis of automotive components considering forming and welding effect. Int. J. Automot. Technol. 18(1), 97–102 (2016) 2. Fu, Y., Li, W.Y., Yang, X.W., Ma, T.J., Vairis, A.: The effects of forging pressure and temperature field on residual stresses in linear friction welded Ti6Al4V joints. Adv. Manuf. 4(4), 314–321 (2016) 3. Casavola, C., Lamberti, L., Pappalettere, C., Tattoli, F.: A comprehensive numerical stress – strain analysis of laser beam butt-welded titanium compared with austenitic steel joints. J. Strain Anal. Eng. Des. 45(7), 535–554 (2010) 4. Casavola, C., Pappalettere, C.: Discussion on local approaches for the fatigue design of welded joints. Int. J. Fatigue. 31(1), 41–49 (2009) 5. Casavola, C., Pappalettere, C.: Application of WEL.FA.RE. method on aluminum alloy welded joints. In: Proceedings of the 2005 SEM Annual Conference and Exposition on Experimental and Applied Mechanics, pp. 1555–1562 (2005) 6. Casavola, C., Campanelli S., Pappalettere, C.: Experimental analysis of residual stresses in the selective laser melting process. Society for Experimental Mechanics – 11th International Congress and Exhibition on Experimental and Applied Mechanics 2008, vol. 3, pp. 1479–1486 (2008) 7. Alam, M.K., Edrisy, A., Urbanic, J., Pineault, J.: Microhardness and stress analysos pf laser-cladded AISI 420 martensitic stainless steel. J. Mater. Eng. Perform. 1, 1–9 (2017) 8. Araghchi, M., Mansouri, H., Vafaei, R., Guo, Y.: A novel cryogenic treatment for reduction of residual stresses in 2024 aluminum alloy. Mater. Sci. Eng. A. 689, 48–52 (2017) 9. McDonach, A., McKelvie, P., MacKenzie, P., Walker, C.A.: Improved Moiré interferometry and applications in fracture mechanics, residual stress and damaged composites. Exp. Tech. 7(6), 20–24 (1983) 10. Antonov, A.: Development of the method and equipment for holographic inspection of residual-stresses in welded structures. Weld. Prod. 30, 41–43 (1983) 11. Hung, Y.Y., Ho, H.P.: Shearography: an optical measurement technique and applications. Mater. Sci. Eng. R. Rep. 49(3), 61–87 (2005) 12. Findeis, D., Gryzagoridis, J.: Determining residual stresses with the aid of optical interference techniques. In: Conference Proceedings of the Society for Experimental Mechanics Series, vol. 4, pp. 277–284 (2013) 13. Peckersky, M.J., Miller, R.F., Vikram, C.S.: Residual stress measurements with laser speckle correlation interferometry and local heat treating. Opt. Eng. 34(10), 2964–2971 (1995) 14. Viotti, M.R., Albertazzi Jr., A., Kaufmann, G.H.: Measurement of residual stresses using local heating and a radial in-plane speckle interferometer. Opt. Eng. 44(u), 093606 (2005) 15. Viotti, M.R., Sutério, R., Albertazzi Jr., A., Kaufmann, G.H.: Residual stress measurement using a radial in-plane speckle interferometer and laser annealing: preliminary results. Opt. Lasers Eng. 42(1), 71–84 (2004) 16. Barile, C., Casavola, C., Pappalettera, G., Pappalettere, C.: Feasibility of local stress relaxation by laser annealing and X-ray measurement. Strain. 49(5), 393–398 (2013) 17. Barile, C., Casavola, C., Pappalettera, G., Pappalettere, C.: Preliminary analysis for a new approach to relieve residual stresses by laser heating. In: 11th IMEKO TC15 Youth Symposium on Experimental Solid Mechanics 2012, pp. 77–82 (2012)
RkJQdWJsaXNoZXIy MTMzNzEzMQ==