65 citations · 241 across the 19 of their papers we have counts for
21 papers
Grain Boundary Phase Transitions Enable Diffusionless Climb of Disconnections
Md Sharier Nazim, Giacomo Po, Nikhil Chandra Admal
Dislocation-grain boundary (GB) interactions govern the mechanical response of polycrystalline materials by controlling dislocation absorption, transmission, and interfacial plasti…
Irradiation-Driven Recrystallization in Fusion-Grade Tungsten: A Mesoscale, Microstructure-Aware Model
Jinxin Yu, Sicong He, Giacomo Po +3
Tungsten (W) is the leading candidate material for plasma-facing components in fusion reactors, yet its upper operational temperature is limited by premature grain growth and recry…
Plasticity in irradiated FeCrAl nanopillars investigated using discrete dislocation dynamics
Yash Pachaury, George Warren, Janelle P. Wharry +2
In this paper, we investigate plasticity in irradiated FeCrAl nanopillars using discrete dislocation dynamics simulations (DDD), with comparisons to transmission electron microscop…
A discrete dislocation dynamics study of precipitate bypass mechanisms in nickel-based superalloys
Sabyasachi Chatterjee, Yang Li, Giacomo Po
Order strengthening in nickel-based superalloys is associated with the extra stress required for dislocations to bypass the precipitates distributed in the matrix. A rich…
Discrete Dislocation Dynamics for Crystal RVEs. Part 1: Periodic Loop Kinematics
Yash Pachaury, Giacomo Po, Anter El-Azab
A novel implementation of the dislocation flux boundary condition in discrete dislocation dynamics is presented. The continuity of the individual dislocation loops in a periodic re…
Data-mining of dislocation microstructures: concepts for coarse-graining of internal energies
Hengxu Song, Nina Gunkelmann, Giacomo Po +1
Continuum models of dislocation plasticity require constitutive closure assumptions, e.g., by relating details of the dislocation microstructure to energy densities. Currently, the…
Plasticity without phenomenology: a first step
Sabyasachi Chatterjee, Giacomo Po, Xiaohan Zhang +2
A novel, concurrent multiscale approach to meso/macroscale plasticity is demonstrated. It utilizes a carefully designed coupling of a partial differential equation (pde) based theo…
Inference and Prediction of Nanoindentation Response in FCC Crystals: Methods and Discrete Dislocation Simulation Examples
Michail Tzimas, John Michopoulos, Giacomo Po +2
Nanoindentation, a common technique for probing the mechanical properties of crystalline materials, exhibits both surface and bulk-dominated responses that are linked to the parent…
The -invariant and topological pathways to influence sub-micron strength and crystal plasticity
Stefanos Papanikolaou, Giacomo Po
In small volumes, sample dimensions are known to strongly influence mechanical behavior, especially strength and crystal plasticity. This correlation fades away at the so-called me…
The Green tensor of Mindlin's anisotropic first strain gradient elasticity
Giacomo Po, Nikhil Chandra Admal, Markus Lazar
We derive the Green tensor of Mindlin's anisotropic first strain gradient elasticity. The Green tensor is valid for arbitrary anisotropic materials, with up to 21 elastic constants…
A unified framework for polycrystal plasticity with grain boundary evolution
Nikhil Chandra Admal, Giacomo Po, Jaime Marian
Plastic deformation in polycrystals is governed by the interplay between intra-granular slip and grain boundary-mediated plasticity. However, while the role played by bulk dislocat…
Diffuse-interface polycrystal plasticity: Expressing grain boundaries as geometrically necessary dislocations
Nikhil Chandra Admal, Giacomo Po, Jaime Marian
The standard way of modeling plasticity in polycrystals is by using the crystal plasticity model for single crystals in each grain, and imposing suitable traction and slip boundary…
A non-singular theory of dislocations in anisotropic crystals
Giacomo Po, Markus Lazar, Nikhil Chandra Admal +1
We develop a non-singular theory of three-dimensional dislocation loops in a particular version of Mindlin's anisotropic gradient elasticity with up to six length scale parameters.…
Controlling Strain Bursts and Avalanches at the Nano-to-Micro Scale
Yinan Cui, Giacomo Po, Nasr Ghoniem
We demonstrate, through 3-dimensional discrete dislocation dynamics simulations, that the com- plex dynamical response of nano and micro crystals to external constraints can be tun…
Comparison of dislocation density tensor fields derived from discrete dislocation dynamics and crystal plasticity simulations of torsion
Reese Jones, Jonathan Zimmerman, Giacomo Po
The importance of accurate simulation of the plastic deformation of ductile metals to the design of structures and components is well-known. Many techniques exist that address the…
A phenomenological dislocation mobility law for bcc metals
Giacomo Po, Yinan Cui, David Rivera +4
Dislocation motion in body centered cubic (bcc) metals displays a number of specific features that result in a strong temperature dependence of the flow stress, and in shear deform…
Formation and interaction mechanisms of dipolar dislocation loops in fcc metals
Can Erel, Giacomo Po, Tamer Crosby +1
Dipolar dislocation loops, prevalent in fcc metals, are widely recognized as controlling many physical aspects of plastic deformation. We present results of 3D dislocation dynamics…
The atomistic representation of first strain-gradient elastic tensors
Nikhil Chandra Admal, Jaime Marian, Giacomo Po
We derive the atomistic representations of the elastic tensors appearing in the linearized theory of first strain-gradient elasticity for an arbitrary multi-lattice. In addition to…
Microstructural Comparison of the Kinematics of Discrete and Continuum Dislocations Models
Stefan Sandfeld, Giacomo Po
The Continuum Dislocation Dynamics (CDD) theory and the Discrete Dislocation Dynamics (DDD) method are compared based on concise mathematical formulations of the coarse graining of…
Atomistically enabled nonsingular anisotropic elastic representation of near-core dislocation stress fields in -iron
Dariush Seif, Giacomo Po, Matous Mrovec +3
The stress fields of dislocations predicted by classical elasticity are known to be unrealistically large approaching the dislocation core, due to the singular nature of the theory…
The solid angle and the Burgers formula in the theory of gradient elasticity: line integral representation
Markus Lazar, Giacomo Po
A representation of the solid angle and the Burgers formula as line integral is derived in the framework of the theory of gradient elasticity of Helmholtz type. The gradient versio…