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Item type:Publication, Access status: with files , Verbesserung der Effizienz dynamischer Simulationen mithilfe hierarchischer Platten- und Schalenformulierungen(Technische Universität Dresden, 2026-05-26); ; Die Stabilität expliziter Zeitintegrationsverfahren ist durch eine kritische Zeitschrittweite begrenzt, die bei schubweichen Platten- und Schalenmodellen von der höchsten Frequenz der Querschubmoden abhängt. Um die kritische Zeitschrittweite zu erhöhen und damit die Rechenzeit zu verkürzen werden häufig Massenskalierungsmethoden verwendet. Eine Herausforderung ist dabei, einen guten Kompromiss zwischen Rechenzeit und Genauigkeit zu finden. Hierarchische Platten- und Schalenformulierungen, ursprünglich zur Vermeidung von Querschublocking entwickelt, ermöglichen eine selektive Skalierung der Trägheit der Querschubmoden ohne die Genauigkeit der Biegemoden wesentlich zu beeinträchtigen. Diese bereits als intrinsisch lockingfrei bekannten hierarchischen Formulierungen erlauben also auch eine intrinsisch selektive Massenskalierung.Publicationtype: Conference Paper21 12 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Selective mass scaling for Timoshenko beam and Mindlin plate elements based on the discrete strain gap methodPublicationtype: Conference Paper36 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Selective mass scaling for Timoshenko beam and Mindlin plate elements based on the discrete strain gap method(Institute of Structural Analysis and Antiseismic Research National Technical University of Athens, 2025-06); ; ; The conditional stability of explicit time integration algorithms limits the critical time step size, which depends on the highest natural frequency of the discretized problem. For shear deformable structural finite element formulations, efficiency is typically limited by the highest transverse shear frequencies. Selective mass scaling (SMS) methods aim at selectively scaling the high frequencies while preserving the important low frequency content. In particular, recent SMS concepts, which are inspired by the discrete strain gap (DSG) method [1] and, thus, are denoted as DSGSMS concepts, result in effective and accurate methods, which naturally preserve both linear and angular momentum. In this contribution, we extend previous work on DSGSMS for shear deformable element formulations [2] with respect to several aspects. First, we perform a theoretical analysis of the DSGSMS method that provides new insight into spectral properties and analytical time step estimates. Second, we extend the DSGSMS method from Timoshenko beam elements to Mindlin plate elements. Third, we test the extended concept with respect to spectral accuracy and the transient behavior in explicit time integration.Publicationtype: Conference Paper52 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Intrinsically selective mass scaling with hierarchic plate formulationsThe critical time step in explicit time integration methods depends on the highest natural angular frequency of the discretized problem. For shear deformable beam, plate and shell formulations, efficiency is therefore typically limited by the highest transverse shear frequencies, which are mostly of minor importance for the structural response. Direct parametrization using transverse shear variables within hierarchic structural element formulations allows a selective scaling of transverse shear frequencies in a simple manner, while bending frequencies remain practically unaffected. In particular, the novel concept of intrinsically selective mass scaling (ISMS) results in an efficient method that features high accuracy and preserves both linear and angular momentum for both consistent and lumped mass matrices. In addition, ISMS preserves the diagonal structure of lumped mass matrices. Similar to the underlying intrinsically locking-free, hierarchic concept for shear deformable structural element formulations, ISMS retains its beneficial properties for any smooth discretization scheme. In this contribution, we extend recent research on ISMS for beam formulations to the case of shear deformable plate formulations. We test our novel concept with respect to accuracy and efficiency by means of selected numerical experiments. We study both frequency spectra and the transient behavior in explicit time integration. To demonstrate the generality of ISMS, exemplarily both isogeometric discretizations based on B-splines and meshfree discretizations using local maximum-entropy approximants are investigated.Publicationtype: Journal Article29 50 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Hierarchische Formulierungen für statische und dynamische Analysen von Flächentragwerken(Institut für Baustatik, Technische Universität Hamburg, 2024-03); ; ; Hierarchische Balken-, Platten- und Schalenformulierungen basieren auf einer geschickten Reparametrisierung der kinematischen Gleichungen, die sich für neuartige, glatte Diskretisierungsverfahren als vorteilhaft erweist. Im vorliegenden Beitrag werden die intrinsischen Eigenschaften des hierarchischen Konzepts anhand statischer und dynamischer Analysen von Flächentragwerken aufgezeigt und diskutiert.Publicationtype: Conference Paper35 130 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Transverse shear parametrization in hierarchic large rotation shell formulationsConsistent treatment of large rotations in common Reissner–Mindlin formulations is a complicated task. Reissner–Mindlin formulations that use a hierarchic parametrization provide an elegant way to facilitate large rotation shell analyses. This can be achieved by the assumption of linearized transverse shear strains, resulting in an additive split of strain components, which technically simplifies implementation of corresponding shell finite elements. The present study aims at validating this assumption by systematically comparing numerical solutions with those of a newly implemented hierarchic and fully nonlinear Reissner–Mindlin shell element.Publicationtype: Journal Article37 42 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Finite element technology-based selective mass scaling for explicit dynamic analyses of thin-walled structures using solid elements(Institute of Research and Development for Computational Methods in Engineering Sciences (ICMES), 2023); ; We present a novel class of selective mass scaling (SMS) concepts in the context of explicit dynamic analyses of thin-walled structures using solid elements. The novel SMS schemes are based on the discrete strain gap (DSG) method [1], a method from the field of finite element technology (FET). Thus, they are denoted as DSGSMS schemes and they extend the initial work of [2] for shear deformable structural element formulations to the application in thin solid elements. We show that these novel DSGSMS concepts naturally preserve both translational and rotational inertia and possess high accuracy. Additionally, having non-linear problems including large rotations in mind, we show how efficient isotropic DSGSMS concepts can be developed such that the need for reassembly of scaled mass matrices is avoided.Publicationtype: Conference PaperScopus© Citations 1 83 164 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Finite element technology-based selective mass scaling for shear deformable strucural element formulations(Institute of Research and Development for Computational Methods in Engineering Sciences (ICMES), 2023); Scopus© Citations 1 54 162 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , A study on the approximation power of NURBS and the significance of exact geometry in isogeometric pre-buckling analyses of shells(Elsevier, 2022-06-09); ; ; ; We present a comprehensive study on the approximation power of NURBS and the significance of exact geometry in stability analyses of shells. Pre-buckling analyses are carried out to estimate the critical load levels and the initial buckling patterns. Various finite element solutions obtained with the commercial code ANSYS are compared with solutions from theisogeometric version of the finite element method, using our in-house code NumPro. In some problem setups, the isogeometric shell elements provide superior accuracy compared to standard (as opposed to isogeometric) shell finite elements, requiring only a fractional amount of degrees of freedom for the same level of accuracy. The present study systematically investigates the sources of this superior accuracy of the isogeometric approach. In particular, hypotheses are tested concerning the influence of exact geometry and smoothness of splines.Publicationtype: Journal ArticleScopus© Citations 8 147 322 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Strategy for Preventing Membrane Locking Through ReparametrizationThe contribution takes up the concept of preventing locking a priori in the theory of thin-walled structures instead of curing it during discretization. After briefly summarizing the successful concept for avoiding transverse shear locking through reparametrization of primary variables for beams, plates and shells we concentrate on the same approach for preventing also membrane locking. Here, we describe first steps referring to the plane curved Bernoulli beam as a conceptual proof for the new method. Inspired by the so-called Mixed Displacement variational method we discuss three variants of replacing primary displacement parameters by alternative variables.Publicationtype: Book Part92