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Asynchronous time integration while achieving zero interface energy
Dvořák, Radim ; Kolman, Radek ; Falta, J. ; Neühauserová, M.
This contribution deals with an asynchronous direct time integration of the finite-element model. The proposed method is applied to the phenomenon of wave propagation through an elastic linear continuum. The numerical model is partitioned into individual subdomains using the domain decomposition method by means of localized Lagrange multipliers. For each subdomain, different time discretizations are used. No restrictions for relation between subdomain’s time steps are imposed. The coupling of the subdomains is forced by an acceleration continuity condition. Additionally, we use the a posteriori technique to also provide the displacement and velocity continuity at the interfaces, and hence we obtain exact continuity of all three kinematic fields. The proposed method is experimentally validated using the modified SHPB (split Hopkinson pressure bar) setup.
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Numerical comparison of different choices of interface weights in the BDDC method
Čertíková, M. ; Burda, P. ; Šístek, Jakub
Balancing Domain Decomposition by Constraints (BDDC) belongs to the class of primal substructuring Domain Decomposition (DD) methods. DD methods are iterative methods successfully used in engineering to parallelize solution of large linear systems arising from discretization of second order elliptic problems. Substructuring DD methods represent an important class of DD methods. Their main idea is to divide the underlying domain into nonoverlapping subdomains and solvemany relatively small, local problems on subdomains instead of one large problem on the whole domain. In primal methods, it has to be specified how to distribute interface residuals among subdomains and how to obtain global, interface values of solution from local values on adjacent subdomains. Usually a weighted average is used with some simple choice of weights.
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Approaches to parallel implementation of the BDDC method
Šístek, Jakub ; Burda, P. ; Čertíková, M. ; Novotný, J.
During past several years, we have implemented and tested various approaches to domain decomposition methods, especially the Balancing Domain Decomposition Method by Constraints (BDDC). The goal of this paper is to summarize our experience with parallel implementation of such algorithms and to suggest ways to an implementation of the BDDC method that would be efficient on very large number of cores of computers of near future.
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On selections of constraints for the BDDC method
Čertíková, M. ; Šístek, Jakub ; Novotný, J. ; Burda, P.
The Balancing Domain Decomposition by Constraints (BDDC) method is an iterative substructuring domain decomposition method which uses a coarse space. The choice of coarse constraints on continuity has strong influence on convergence of the method. The goal of this paper is to compare the performance of several algorithms for selection of the coarse constraints applied to both test and industrial 3D linear elasticity problems and confront results obtained for typical test problems with results for industrial problems.
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FETI Method
Sysala, Stanislav
In this paper we describe the derivation of the standard FETI method and its iterative alghorithm based on the projected conjugate gradient method.We describe the derivation of the FETI method and formulate the original problem as a saddle-point or a dual dual problem.
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