Modeling Near-Crack-Tip Plasticity at Nano- to Micro- Scales

Abstract

Several efforts that are aimed at understanding the plastic deformation mechanisms related to crack propagation at the nano-, meso-and micro-length scales including atomistic simulation, discrete dislocation plasticity, strain gradient plasticity and crystal plasticity are discussed. The paper focuses on discussion of newly developed methodologies and their application to understanding damage processes in aluminum and its alloys. Examination of plastic mechanisms as a function of increasing length scale illustrates increasingly complex phenomena governing plasticity.

Analysis of cell size effects in atomistic crack propagation

“…Cracks (and other defects) initiate and propagate via atomistic mechanisms, which renders the task of creating accurate and efficient simulations of this phenomenon on a large scale particularly difficult [BKG15]. In addition, many of the simulation techniques in operation today rely on simplifying assumptions which are often phenomenological; for example, it is generally unclear under which conditions continuum models become invalid [GSHY10].…”

An Overview of Innovative Strategies for Fracture Mechanics at NASA Langley Research Center

“…For example, Figure 13 depicts the stress-strain response of a single-crystal aluminum loaded in tension using the in-house developed two-dimensional dislocation dynamics code DD-SIM. As shown, both the inelastic plastic yielding together with hardening can be obtained directly from the simulation 24 .…”