Issue 43

D. Gentile, Frattura ed Integrità Strutturale, 43 (2018) 155-170; DOI: 10.3221/IGF-ESIS.43.12 155 Experimental characterization of interlaminar fracture toughness of composite laminates assembled with three different carbon fiber lamina Domenico Gentile University of Cassino and Southern Lazio, Cassino (FR), Italy gentile@unicas.it A BSTRACT . In the present work, the fracture resistance of a carbon fiber composite under mode I and mode II loading have been experimentally determined. For the mode I and II, the energy release rate G has been determinate for each material. In some cases, only a single estimation of G was possible due to problems in the propagation such as extensive fiber bridging and loss of planarity of the running crack. The experimental results relative to DCB tests have been analyzed in order to derive statistical trends. Only the samples for which more than three crack advance data points have been collected are considered in the analysis. The G values are those obtained with the compliance calibration method (CC). For ENF test, determination of critical GII, in addition to the value calculated with the relationship given in the prescription EN6034, other two values, the non linear and visual non linear, are also given. The crack propagation resulted to be unstable for all specimens tested and only a single value of GII could be determined. K EYWORDS . Carbon fiber; Delamination; ENF; DCB. Citation: Gentile, D., Experimental characterization of interlaminar fracture toughness of composite laminates assembled with three different carbon fiber lamina, Frattura ed Integrità Strutturale, 43 (2018) 155-170. Received: 21.09.2017 Accepted: 05.11.2017 Published: 01.01.2018 Copyright: © 2018 This is an open access article under the terms of the CC-BY 4.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. I NTRODUCTION omposites based on carbon fiber are widely used in the field of automobiles, aircrafts, and spacecrafts. These materials, it is well known, give some advantages in terms of specific modulus and specific strength comparing with the traditional metals. Another important point is the possibility to design structures that are more efficient by changing mechanical properties with variable reinforcing methods. For this reason, it is very important to assure the reliability of the components against interlaminar fracture, because the weakest fracture mode depends on the interlaminar crack. The fracture behavior of unidirectional, quasi-isotropic, and woven reinforced laminates carbon fiber composites has been mainly investigated, [1-12]. Interlaminar flaws, or delaminations, can be generated in the composite material during the production process, as a consequence of the contamination of the prepeg which may result in regions with poor adhesion between plies, or they can C