All real materials are heterogeneous, e.g.polycrystalline metal alloys, reinforced concrete, carbon fibre reinforced polymer (CFRP), wood, nuclear graphite or bone.Modelling of such materials involves concurrent simulation of multiple interacting and competing physical processes, acting at different length and time scales, e.g.dislocation flow, ply debonding or separation of atomic layers.In this work we demonstrate a multi-scale fracture framework where cellular automata (CA) represents material evolution, deformation and fracture at micro-or nano-scales and finite elements (FE) are used at structural scales.Fortran coarrays offer simple and intuitive data structures for 3D CA modelling of material microstructures.Fortran 2008 and 2015 coarrays are native Fortran means for SPMD style of parallel programming.CA is a structured grid and thus is well suited for implementation in coarrays.Design of a coarray cellular automata microstructure evolution library CGPACK is described.Simulations of solidification, recrystallisation and grain coarsening, and fracture can be performed at arbitrary length and time scales with CGPACK.We show how coarrays can be used together with an MPI FE library to create a two-way concurrent hierarchical and scalable multi-scale CAFE deformation and fracture framework.A highly portable MPI FE library ParaFEM was used in this work.Both CGPACK and ParaFEM are developed and distributed under BSD license, allowing free use, modification and redistribution in academia and for profit.The CAFE framework is based on mapping coarrays to MPI data structures.There are identical numbers of MPI ranks and coarray images in the framework.Data stored in coarray variables on each coarray image is mapped onto data stored on each MPI process, based on fact that the material and the structure occupy the same physical space.Continuum mechanics quantities, e.g.stress and strain tensors are passed from FE integration points to the CA, where they are distributed over cells (localisation) based on existing damage and microstructure heterogeneity.After each fracture propagation increment at the CA scale, the microstructural damage is encoded in a scalar damage variable (homogenisation) which is passed back to
In this study, theoretical models and design procedures of the behavior of thin-walled simply supported steel beams with an open cross section under a large torsional effect are presented. I-sections were chosen as the cross section types. Firstly, the widely used differential equations for the lateral buckling for the pure bending moment effect in a beam element were adopted for the various moment distributions along the span of the beam. This solution was obtained for both mono-symmetric and bisymmetric sections. The buckling loads were then obtained by using the energy method. When using the energy method to solve the problem, it is possible to locate the load not only on the shear center but also at several points of the section depth. Buckling loads were obtained for six different load types. Results obtained for different load and cross section types were checked with ABAQUS software and compared with several standard rules.
The goal of this paper is to present an efficient algorithm for the numerical solution of elasto-plastic problems in mechanics. These problems with hardening lead to the so-called quasistatic problems, where each nonlinear and nonsmooth time step problem is solved by the semismooth Newton method. In each Newton iteration we have to solve an auxiliary (possibly of large size) linear system of algebraic equations. In this paper, we propose a new approach how to solve such system efficiently using in a sense optimal algorithm based on our Total-FETI variant of FETI (Finite Element Tearing and Interconnecting) domain decomposition method. The efficiency is illustrated by the results of 3D elasto-plastic model benchmark.
This paper presents the design of multi-physic integration tool. The goal is to design and implement a high-level support for integration of existing applications. Each application should implement an interface that allows to steer application and execute data requests. The design supports various coupling strategies, discretization techniques, and also the distributed applications.
