Parallel 3D Finite Element Analysis of Coupled Problems

Margetts, Lee; Leng, Joanna; Smith, I. M.

doi:10.1007/1-4020-5370-3_97

Cited by 5 publications

(2 citation statements)

References 3 publications

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“…The approach has been successful in solving a variety of problem types, from nonlinear material behaviour [32] to coupled systems involving multiphysics, such as Biot consolidation and magneto-hydrodynamics [33]. The software has led to scientific advances in a range of disciplines such as nuclear engineering [34,35], biomechanics [36,37], geomechanics [38] and palaeontology [39].…”

Section: The Fe Part -Parafemmentioning

confidence: 99%

Modelling fracture in heterogeneous materials on HPC systems using a hybrid MPI/Fortran coarray multi-scale CAFE framework

Shterenlikht

Margetts

Cebamanos

2018

Advances in Engineering Software

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A 3D multi-scale cellular automata finite element (CAFE) framework for modelling fracture in heterogeneous materials is described. The framework is implemented in a hybrid MPI/Fortran coarray code for efficient parallel execution on HPC platforms. Two open source BSD licensed libraries developed by the authors in modern Fortran were used: CGPACK, implementing cellular automata (CA) using Fortran coarrays, and ParaFEM, implementing finite elements (FE) using MPI. The framework implements a two-way concurrent hierarchical information exchange between the structural level (FE) and the microstructure (CA). MPI to coarrays interface and data structures are described. The CAFE framework is used to predict transgranular cleavage propagation in a polycrystalline iron round bar under tension. Novel results enabled by this CAFE framework include simulation of progressive cleavage propagation through individual grains and across grain boundaries, and emergence of a macro-crack from merging of cracks on preferentially oriented cleavage planes in individual crystals. Nearly ideal strong scaling up to at least tens of thousands of cores was demonstrated by CGPACK and by ParaFEM in isolation in prior work on Cray XE6. Cray XC30 and XC40 platforms and CrayPAT profiling were used in this work. Initially the strong scaling limit of hybrid CGPACK/ParaFEM CAFE model was 2,000 cores. After replacing all-to-all communication patterns with the nearest neighbour algorithms the strong scaling limit on Cray XC30 was increased to 7,000 cores. TAU profiling on non-Cray systems identified deficiencies in Intel Fortran 16 optimisation of remote coarray operations. Finally, coarray synchronisation challenges and opportunities for thread parallelisation in CA are discussed.

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Section: The Fe Part -Parafemmentioning

confidence: 99%

Modelling fracture in heterogeneous materials on HPC systems using a hybrid MPI/Fortran coarray multi-scale CAFE framework

Shterenlikht

Margetts

Cebamanos

2018

Advances in Engineering Software

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“…The approach has been successful in solving a variety of problem types, from nonlinear material behaviour [23] to coupled systems involving multiphysics, such as Biot consolidation and magneto-hydrodynamics [24]. The software has led to scientific advances in a range of disciplines such as Nuclear Engineering [25,26], Biomechan-ics [27,28], Geomechanics [29] and Palaeontology [30].…”

Section: Cellular Automata Modelling Of Microstructurementioning

confidence: 99%

Fortran coarray/MPIMulti-Scale CAFE for Fracture in Heterogeneous Materials

Shterenlikht¹,

Margetts²,

Cebamanos³

Civil-Comp Proceedings

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General rightsThis document is made available in accordance with publisher policies. Please cite only the published version using the reference above. Full terms of use are available: http://www.bristol.ac.uk/pure/about/ebr-terms AbstractAll 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 1 the FE integration point. The stiffness (Young's modulus) of the integration point is scaled by the damage variable, so that the damage variable of 1 means no damage, and the damage variable of 0 means no remaining load bearing capacity. We show that independently CGPACK and ParaFEM programs can scale up well into tens of thousands of cores on Cray systems. Strong scaling of a hybrid ParaFEM/CGPACK MPI/coarray multi-scale framework was measured on Cray a simulation of a fracture of a steel round bar under tension. That program scales up to 7,000 cores. The...

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