The R-curve method was used to characterize the stable crack growth and the unstable ductile fracture of 3 mm thick polycarbonate sheets. In order to delimit the field of application of this method, several parameters describing the crack growth resistance were employed. The effect of specimen size and geometry was also studied. Besides limitations linked to test specimens size, the different parameters used are shown to aptly describe the tearing process of this material. When the plane stress region is dominant, the J-integral appears to be as a parameter well adapted to characterize ductile fracture. NOMENCLATURE a 0 initial crack length B specimen thickness W specimen width ap, Aap physical crack length and extension ae, Aa e effective crack length and extension Rp plastic-zone length P load 6 load-line displacement U area under P-3 curve K elastic stress intensity factor K~ effective stress intensity factor J J integral /'2o, J0 K and J values at crack initiation Kpop_in K value at pop-in Jpop-in J value at pop-in K~, J, critical values of K and J (maximum load) ~ strain in the thickness direction T tearing modulus
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