Plasticity effects in dynamically loaded nickel aluminide bicrystals

Atomistic simulation of the mechanical response of a nanoporous body-centered cubic metal

“…Mechanical deformation of such nanofoams under extreme conditions is not well understood because experiments that probe pressure-induced nanovoid collapse at the relevant nanoscopic length and ultrashort time scales are extremely difficult with current set-ups, while continuum models might not work at the nanoscale. In recent years, laser-driven shock waves with strain rates of 10 7 -10 9 s À1 have been used to investigate the dynamic behavior of a number of bulk materials [5][6][7][8][9][10], including body-centered cubic (bcc) metals like tantalum [5], vanadium [7] and iron [10]. The use of atomistic molecular dynamics (MD) simulations in conjunction with these experiments has led to the elucidation of important mechanisms of plastic deformation operating in these regimes [9], and to the creation of new constitutive models [11,12].…”

“…Periodic boundary conditions were applied in all directions. The domain was subjected to uniaxial compressive strain along the [0 0 1] direction, with zero lateral strain to mimic shock experiments [5][6][7][8][9][10]. The simulation was conducted at a strain rate of 10 9 s À1 (200 ps, 20% volumetric strain) and at an initial temperature of 300 K. The sample was equilibrated to reach zero pressure and the prescribed initial temperature prior to the application of the uniaxial strain.…”

Accurate Finite Element Simulations of Dynamic Behaviour: Constitutive Models and Analysis with Deep Learning

“…Importantly, investigating the dynamic response under uniaxial strain loading conditions provides valuable insights into metal behaviour, enhancing our ability to establish key parameters for engineering applications [9]. In the gas gun or split-Hopkinson pressure bar (SHPB), this response emerges when uniaxial strain loading surpasses the HEL threshold, resulting in the transforming of a single shock wave into faster elastic and plastic waves, ultimately pushing the material into an elastic-plastic state [10]. Meyers initially established a link between HEL stress and the dynamic yield strength as well as the Poisson's ratio of materials [11].…”