Search results for " Polycrystalline Materials"
showing 4 items of 4 documents
A Grain Boundary Formulation for the Analysis of Three-Dimensional Polycrystalline Microstructures
2013
A 3D grain boundary formulation is presented for the analysis of polycrystalline microstructures. The formulation is expressed in terms of intergranular displacements and tractions, that play an important role in polycrystalline micromechanics, micro-damage and micro-cracking. The artificial morphology is generated by Hardcore Voronoi tessellation, which embodies the main statistical features of polycrystalline microstructures. Each crystal is modeled as an anisotropic elastic region and the integrity of the aggregate is restored by enforcing interface continuity and equilibrium between contiguous grains. The developed technique has been applied to the numerical homogenization of cubic poly…
A computational framework for low-cycle fatigue in polycrystalline materials
2021
Abstract A three-dimensional framework for low-cycle fatigue analysis of polycrystalline aggregates is proposed in this work. First, a cohesive law coupling plasticity and damage is developed for modelling cycle-by-cycle degradation of material interfaces up to complete de-cohesion and failure. The law may model both quasi-static degradation under increasing monotonic load and degradation under cyclic loading, through a coupled plasticity-damage model whose activation and flow rules are formulated in a thermodynamically consistent framework. The proposed interface laws have been then implemented and coupled with a multi-region boundary element formulation, with the aim of analysing low-cycl…
A BOUNDARY ELEMENT FORMULATION FOR MICROMECHANICAL HOMOGENIZATION OF POLYCRYSTALLINE MATERIALS WITH PIEZOELECTRIC COUPLING
2019
A novel boundary element formulation for the evaluation of the effective properties of threedimensional polycrystalline aggregates with piezoelectric coupling is presented. The aggregates are modelled at the scale of their constituent crystals and are artificially generated through Voronoi-Laguerre tessellations. The electro-mechanical behaviour of each crystal is represented upon introducing an ad-hoc mesh of its boundary and a generalised integral representation of the governing equations of the piezoelectric problem. The behaviour of the whole aggregate is then retrieved upon introducing a suitable set of electro-mechanical interface conditions at the grain boundaries. With respect to cl…
A Novel Numerical Formulation for Crystal Plasticity
2016
Crystal plasticity plays a crucial role in the mechanics of polycrystalline materials and it is commonly modeled within the framework of the crystal plasticity finite element method (CPFEM). In this work, an alternative formulation for small strains crystal plasticity is presented. The method is based on a boundary integral formulation for polycrystalline problems and plasticity is addressed using an initial strains approach. Voronoi-type micro-morphologies are considered in the polycrystalline case. A general grain-boundary incremental/iterative algorithm, embedding the flow and hardening rules for crystal plasticity, is developed. The key feature of the method is the expression of the mic…