Dokument-ID Dokumenttyp Verfasser/Autoren Herausgeber Haupttitel Abstract Auflage Verlagsort Verlag Erscheinungsjahr Seitenzahl Schriftenreihe Titel Schriftenreihe Bandzahl ISBN Quelle der Hochschulschrift Konferenzname Quelle:Titel Quelle:Jahrgang Quelle:Heftnummer Quelle:Erste Seite Quelle:Letzte Seite URN DOI Abteilungen
OPUS4-3388 Wissenschaftlicher Artikel Areias, Pedro; Rabczuk, Timon; Dias-da-Costa, D.; Piresh, E.B. Implicit solutions with consistent additive and multiplicative components This work describes an algorithm and corresponding software for incorporating general nonlinear multiple-point equality constraints in a implicit sparse direct solver. It is shown that direct addressing of sparse matrices is possible in general circumstances, circumventing the traditional linear or binary search for introducing (generalized) constituents to a sparse matrix. Nested and arbitrarily interconnected multiple-point constraints are introduced by processing of multiplicative constituents with a built-in topological ordering of the resulting directed graph. A classification of discretization methods is performed and some re-classified problems are described and solved under this proposed perspective. The dependence relations between solution methods, algorithms and constituents becomes apparent. Fracture algorithms can be naturally casted in this framework. Solutions based on control equations are also directly incorporated as equality constraints. We show that arbitrary constituents can be used as long as the resulting directed graph is acyclic. It is also shown that graph partitions and orderings should be performed in the innermost part of the algorithm, a fact with some peculiar consequences. The core of our implicit code is described, specifically new algorithms for direct access of sparse matrices (by means of the clique structure) and general constituent processing. It is demonstrated that the graph structure of the second derivatives of the equality constraints are cliques (or pseudo-elements) and are naturally included as such. A complete algorithm is presented which allows a complete automation of equality constraints, avoiding the need of pre-sorting. Verification applications in four distinct areas are shown: single and multiple rigid body dynamics, solution control and computational fracture. 16 Finite Elements in Analysis and Design 15 31 10.1016/j.finel.2012.03.007 Institut für Strukturmechanik (ISM)
OPUS4-3329 Wissenschaftlicher Artikel Areias, Pedro; Pinto da Costa, A.; Rabczuk, Timon; Queiros de Melo, F. J. M.; Dias-da-Costa, D. An alternative formulation for quasi-static frictional and cohesive contact problems An alternative formulation for quasi-static frictional and cohesive contact problems 17 Computational Mechanics 807 824 Institut für Strukturmechanik (ISM)
OPUS4-3376 Wissenschaftlicher Artikel Areias, Pedro; Rabczuk, Timon; Dias-da-Costa, D. Assumed-metric spherically-interpolated quadrilateral shell element Assumed-metric spherically-interpolated quadrilateral shell element 14 Finite Elements in Analysis and Design 53 67 Institut für Strukturmechanik (ISM)
OPUS4-3357 Wissenschaftlicher Artikel Areias, Pedro; Rabczuk, Timon; Dias-da-Costa, D. Asymmetric Shell Elements Based on a Corrected Updated-Lagrangian Approach Asymmetric Shell Elements Based on a Corrected Updated-Lagrangian Approach CMES: Computer Modeling in Engineering and Sciences Institut für Strukturmechanik (ISM)
OPUS4-3316 Wissenschaftlicher Artikel Jia, Yue; Anitescu, Cosmin; Ghorashi, Seyed Shahram; Rabczuk, Timon; Dias-da-Costa, D. Extended Isogeometric Analysis for Material Interface Problems Extended Isogeometric Analysis for Material Interface Problems Journal of Applied Mathematics Institut für Strukturmechanik (ISM)