Experimental determination of mode I fracture parameters in orthotropic materials by means of Digital Image Correlation

• Published in: Theoretical and applied fracture mechanics Vol. 108; p. 102663
• Main Authors: Cappello, Riccardo, Pitarresi, Giuseppe, Xavier, José, Catalanotti, Giuseppe
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier Ltd 01.08.2020; Elsevier BV
• Subjects: Correlation analysis; Digital image correlation; Digital imaging; Energy domain integral; Fracture mechanics; J integral; Least squares fitting; Mathematical analysis; Parameters; Stress intensity factor; Stress intensity factors; J-integral; Least squares fitting; Stress intensity factor; Energy domain integral; Digital image correlation
• ISSN: 0167-8442; 1872-7638
• DOI: 10.1016/j.tafmec.2020.102663

•Fracture parameters are measured using DIC data.•Three different approaches were proposed and implemented.•A comparative experimental study using an IM7/8552 cross ply laminates was conducted.•The effect of different experimental parameters is analysed and discussed.•It was concluded that the different methodologies lead to the same results. The mode I fracture parameters for an orthotropic body are directly calculated from full-field deformation measurements provided by Digital Image Correlation (DIC). Three complementary and direct approaches are evaluated and compared: (i) the determination of the Stress Intensity Factor (SIF) by fitting the displacement field using the analytical expression proposed by Lekhnitskii; (ii) the determination of the J-Integral by using the Energy Domain Integral (EDI) formulation on the raw DIC data; and (iii) the calculation of the J-Integral using the EDI approach on the displacement data fitted using Lekhnitskii’s formulation. A comparative experimental study is performed by testing an IM7/8552 cross-ply laminate, and the effect of different parameters is analysed and discussed. The outcomes of this work show that, if an accurate choice of the parameters is performed, the different approaches lead to the same results.