170 research outputs found
A novel block non-symmetric preconditioner for mixed-hybrid finite-element-based flow simulations
In this work we propose a novel block preconditioner, labelled Explicit
Decoupling Factor Approximation (EDFA), to accelerate the convergence of Krylov
subspace solvers used to address the sequence of non-symmetric systems of
linear equations originating from flow simulations in porous media. The flow
model is discretized blending the Mixed Hybrid Finite Element (MHFE) method for
Darcy's equation with the Finite Volume (FV) scheme for the mass conservation.
The EDFA preconditioner is characterized by two features: the exploitation of
the system matrix decoupling factors to recast the Schur complement and their
inexact fully-parallel computation by means of restriction operators. We
introduce two adaptive techniques aimed at building the restriction operators
according to the properties of the system at hand. The proposed block
preconditioner has been tested through an extensive experimentation on both
synthetic and real-case applications, pointing out its robustness and
computational efficiency
SOLID-SHELL FINITE ELEMENT MODELS FOR EXPLICIT SIMULATIONS OF CRACK PROPAGATION IN THIN STRUCTURES
Crack propagation in thin shell structures due to cutting is conveniently simulated
using explicit finite element approaches, in view of the high nonlinearity of the problem. Solidshell
elements are usually preferred for the discretization in the presence of complex material
behavior and degradation phenomena such as delamination, since they allow for a correct
representation of the thickness geometry. However, in solid-shell elements the small thickness
leads to a very high maximum eigenfrequency, which imply very small stable time-steps. A new
selective mass scaling technique is proposed to increase the time-step size without affecting
accuracy. New ”directional” cohesive interface elements are used in conjunction with selective
mass scaling to account for the interaction with a sharp blade in cutting processes of thin ductile
shells
TNL: NUMERICAL LIBRARY FOR MODERN PARALLEL ARCHITECTURES
We present Template Numerical Library (TNL, www.tnl-project.org) with native support of modern parallel architectures like multi–core CPUs and GPUs. The library offers an abstract layer for accessing these architectures via unified interface tailored for easy and fast development of high-performance algorithms and numerical solvers. The library is written in C++ and it benefits from template meta–programming techniques. In this paper, we present the most important data structures and algorithms in TNL together with scalability on multi–core CPUs and speed–up on GPUs supporting CUDA
Modeling and Visualization of Multi-material Volumes
The terminology of multi-material volumes is discussed. The classification of the multi-material volumes is given from the spatial partitions, spatial domain for material distribution, types of involved scalar fields and types of models for material distribution and composition of several materials points of view. In addition to the technical challenges of multi-material volume representations, a range of key challenges are considered before such representations can be adopted as mainstream practice
Software for Exascale Computing - SPPEXA 2016-2019
This open access book summarizes the research done and results obtained in the second funding phase of the Priority Program 1648 "Software for Exascale Computing" (SPPEXA) of the German Research Foundation (DFG) presented at the SPPEXA Symposium in Dresden during October 21-23, 2019. In that respect, it both represents a continuation of Vol. 113 in Springer’s series Lecture Notes in Computational Science and Engineering, the corresponding report of SPPEXA’s first funding phase, and provides an overview of SPPEXA’s contributions towards exascale computing in today's sumpercomputer technology. The individual chapters address one or more of the research directions (1) computational algorithms, (2) system software, (3) application software, (4) data management and exploration, (5) programming, and (6) software tools. The book has an interdisciplinary appeal: scholars from computational sub-fields in computer science, mathematics, physics, or engineering will find it of particular interest
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