Title: Modeling Dislocations in a Polycrystal using the Generalized Finite Element Method (GFEM) Speaker: Joshua Robbins, Sandia National Laboratories Date/Time: Thursday, 15 July 2010, 2PM (MDT) Sandia, NM, CSRI / Rm 90, 1PM (PDT) Sandia, CA, Bldg 942 / Rm. 1341 (video link) Location: CSRI Building/Room 90 (Sandia NM) Brief Abstract: Modeling the interaction of dislocations with internal boundaries and free surfaces is essential to understanding the effect of material microstructure on dislocation motion. However, discrete dislocation dynamics methods rely on infinite domain solutions of dislocation fields which makes modeling of heterogeneous materials difficult. A finite domain dislocation dynamics capability is under development that resolves both the dislocation array and polycrystalline structure in a compatible manner so that free surfaces and material interfaces are easily treated. In this approach the polycrystalline structure is accommodated using the GFEM [1] and the displacement due to the dislocation array is added to the displacement approximation [2]. In this talk the method and its implementation are presented, as well as some representative results from large scale simulations of dislocation motion in cubic nano-domain nickel alloy. Particular attention is paid to the effect of grain size on polycrystalline strength. References CSRI POC: John Aidun, 505-844-1209 |