Issue 30

P. Lorenzino et alii, Frattura ed Integrità Strutturale, 30 (2014) 369-374; DOI: 10.3221/IGF-ESIS.30.44 374 Figure 9 : Analysis of the specimen immediately after plastic collapse. Grain size = 0.07 mm. C ONCLUSIONS n this work, we developed a simple procedure for implementing digital image correlation (DIC) on resonance fatigue testing machines. The experimental difficulties typically encountered with this type of machine were easily circumvented and deformation resulting from crack growth was analyzed without the need to stop the tests in order to acquire images. The DIC technique affords high magnifications with no image displacement errors. Preliminary results for crack propagation and its plastic zone were obtained. Under special conditions, it is even possible to study crack–microstructure interactions and observe how grain boundaries act as barriers to propagation of the crack and its plastic zone. Our group is currently engaged in refining the surface spot pattern in order to increase the precision of the technique, and in using microscopes of similar size and weight but higher resolution and magnification. A CKNOWLEDGEMENTS he authors are grateful to Spain’s Ministry of Education and Science for funding this work through Projects DPI2008-01100 and DPI2011-27019, and to the Andalusian Regional Government for additional support through Project P07-TEP-03045. R EFERENCES [1] http://www.correlatedsolutions.com . (January 2014). [2] Sun, Z., Lyons, J. S., McNeill, S. R. Measuring Microscopic Deformations with Digital Image Correlation Optics and Lasers in Engineering, 27 (1997) 409-428. [3] Vanlanduit, S., Vanherzeele, J., Longo, R., Guillaume, P., A digital image correlation method for fatigue test experiments Optics and Lasers in Engineering, 47 (2009) 371-378. [4] http://www.rumul.ch Comparision of costs between Resonant Testing Machine and Servohydraulic testing machine. (January 2014) [5] Carroll, J. D., Abuzaid, W., Lambros, J., Sehitoglu, H., High resolution digital image correlation measurements of strain accumulation in fatigue crack growth, International Journal of Fatigue, 57 (2013) 140-150. [6] Lorenzino, P., Navarro, A., Krupp, U., Naked eye observations of microstructurally short fatigue cracks, International Journal of Fatigue, 56 (2013) 8-16. [7] Lorenzino, P., Fatiga en componentes con concentradores de tención bajo carga en modo I, Tesis doctoral, Sevilla, España, (2012) 17. [8] Lorenzino, P., Navarro, A, Initiation and growth behavior of very-long microstructurally short fatigue cracks, Frattura ed Integrità Strutturale, 25 (2013) 138-144. I T