The peridynamic theory has been developed to address problems in solid mechanics regarding fracture through its integral non-local basis. It has been successful in predicting brittle cracking, however, uncertainty still remains with regards to mixed mode and ductile fracture. This work presents a study in using peridynamics to simulate fracture in mixed mode or ductile type fractures. The results are presented as a quantitative comparison between experimental tests and numerical simulations. Standard compact tension tests were performed on polymethyl methacrylate (PMMA), stainless steel 304L and aluminium 1200H4 to obtain the respective JR-curves and critical energy release rates, Jic. In addition, digital image correlation was employed to allow for qualitative observation of the fracture process and choice in peridynamic input parameters. An equivalent critical stretch was determined for each material and applied to an Arcan geometry. It is shown that the energy release rate for mode I and mode II should be considered separately. Mixed mode type failures cannot be simulated accurately by a single critical stretch criterion. Furthermore, ductile fracture requires careful consideration when selecting peridynamic input parameters.

Relata-se a ocorrência de Learedius learedi Price 1934 (Digenea, Spirorchiidae) em Chelonia mydas Linnaeus 1758 (Testudines, Chelonidae) no Brasil. Onze animais foram examinados e destes, 54,6% estavam parasitados. Duzentos e cinqüenta e cinco exemplares de L. learedi foram recuperados de órgãos (coração, fígado, baço, pulmões, rins, mesentério) e do lavado corporal dos animais. Os resultados contribuem para o conhecimento da helmintofauna de quelônios marinhos e sua distribuição geográfica. Este é o primeiro registro da ocorrência de L. learedi na região do Atlântico Sul Ocidental.

This study reports the occurrence of Learedius learedi Price 1934 (Digenea, Spirorchiidae) in Chelonia mydas Linnaeus 1758 (Testudines, Chelonidae) in Brazil. Eleven animals were included in this study, 54.6 % of them were parasitized. Two hundred and fifty five parasite specimens were recovered from heart, liver, spleen, lungs, kidneys, mesenterium, and body wash. Results contribute to the knowledge about the helminthofauna of marine chelonian and their geographical distribution. This is the first report of L. learedi in the Southwestern Atlantic.