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In the last few decades, great effort has been spent on advanced material testing and the development of damage models intended to estimate the ductility and fracture of ductile metals. While most studies focused on static testing are applied at room temperatures only, in this paper, multiaxial tests have been executed to investigate the effects of dynamic action and temperature on the mechanical and fracture behavior of an API X65 steel. To this end, a Split Hopkinson Bar (SHB) facility for dynamic tests, and a uniaxial testing machine equipped with a high-temperature furnace, were used. Numerical simulations of the experiments were setup for calibration and validation purposes. Based on the experimental results, the Johnson–Cook and Zerilli–Armstrong plasticity models were first tuned, resulting in a good experimental–numerical match. Secondly, the triaxiality and Lode angle dependent damage models proposed by Bai–Wierzbicki and Coppola–Cortese were also calibrated. The comparison of the fracture surfaces predicted by the damage models under different loading conditions showed, as expected, an overall significant increase in ductility with temperature; an appreciable increase in ductility was also observed with the increase in strain rate, in the range of low and moderate triaxialities. [ABSTRACT FROM AUTHOR]

The interesting properties of Al 6061 aluminum foams have boosted the research on the correlation between foam composition and morphology and its mechanical response under dynamic conditions. In this study, ingots of an Al 6061-T4 foam were sectioned and analyzed in order to determine their microstructural and morphological characteristics, and then quasi-static and dynamic tests (10−3 to 3 × 102 s−1) were carried out to determine the material mechanical behavior. Dynamic tests, carried out by using the split Hopkinson bar, highlighted that the studied foam is characterized by a very good energy absorption capability, due to its ductile behavior. Nevertheless, the conducted research showed that cell morphology and distribution affect its mechanical behavior in dynamic conditions in which localized cell collapse may result in a decreased energy absorption and efficiency of the foam. [ABSTRACT FROM AUTHOR]