Dokument-ID Dokumenttyp Verfasser/Autoren Herausgeber Haupttitel Abstract Auflage Verlagsort Verlag Erscheinungsjahr Seitenzahl Schriftenreihe Titel Schriftenreihe Bandzahl ISBN Quelle der Hochschulschrift Konferenzname Bemerkung Quelle:Titel Quelle:Jahrgang Quelle:Heftnummer Quelle:Erste Seite Quelle:Letzte Seite URN DOI Zugriffsart Link Abteilungen OPUS4-10589 Konferenzveröffentlichung Tran, Ngoc Trinh, Trinh.tran@fh-aachen.de; Trinh, Tu Luc, ; Dao, Ngoc Tien, ; Giap, Van Tan, ; Truong, Manh Khuyen, ; Dinh, Thuy Ha, ; Staat, Manfred, m.staat@fh-aachen.de Limit and shakedown analysis of structures under random strength Direct methods comprising limit and shakedown analysis is a branch of computational mechanics. It plays a significant role in mechanical and civil engineering design. The concept of direct method aims to determinate the ultimate load bearing capacity of structures beyond the elastic range. For practical problems, the direct methods lead to nonlinear convex optimization problems with a large number of variables and onstraints. If strength and loading are random quantities, the problem of shakedown analysis is considered as stochastic programming. This paper presents a method so called chance constrained programming, an effective method of stochastic programming, to solve shakedown analysis problem under random condition of strength. In this our investigation, the loading is deterministic, the strength is distributed as normal or lognormal variables. Hanoi Nha xuat ban Khoa hoc tu nhien va Cong nghe (Verlag Naturwissenschaft und Technik) 2022 8 Proceedings of (NACOME2022) The 11th National Conference on Mechanics, Vol. 1. Solid Mechanics, Rock Mechanics, Artificial Intelligence, Teaching and Training, Hanoi, December 2-3, 2022 978-604-357-084-7 510 518 weltweit https://www.researchgate.net/publication/366053333_Shakedown_analysis_of_structures_under_random_strength_by_chance_constrained_programming Fachbereich Medizintechnik und Technomathematik OPUS4-6830 Teil eines Buches Tran, Thanh Ngoc, tran@fh-aachen.de; Staat, Manfred, m.staat@fh-aachen.de Uncertainty multimode failure and shakedown analysis of shells This paper presents a numerical procedure for reliability analysis of thin plates and shells with respect to plastic collapse or to inadaptation. The procedure involves a deterministic shakedown analysis for each probabilistic iteration, which is based on the upper bound approach and the use of the exact Ilyushin yield surface. Probabilistic shakedown analysis deals with uncertainties originated from the loads, material strength and thickness of the shell. Based on a direct definition of the limit state function, the calculation of the failure probability may be efficiently solved by using the First and Second Order Reliability Methods (FORM and SORM). The problem of reliability of structural systems (series systems) is handled by the application of a special technique which permits to find all the design points corresponding to all the failure modes. Studies show, in this case, that it improves considerably the FORM and SORM results. Cham Springer 2015 19 Direct methods for limit and shakedown analysis of structures / eds. Paolo Fuschi ... 978-3-319-12927-3 (print) ; 978-3-319-12928-0 (online) 279 298 10.1007/978-3-319-12928-0_14 bezahl http://doi.org/10.1007/978-3-319-12928-0_14 Fachbereich Medizintechnik und Technomathematik OPUS4-208 Konferenzveröffentlichung Staat, Manfred, m.staat@fh-aachen.de; Tran, Thanh Ngoc, tran@fh-aachen.de; Pham, Phu Tinh, Limit and shakedown reliability analysis by nonlinear programming 7th International Conference on Reliability of Materials and Structures (RELMAS 2008). June 17 - 20, 2008 ; Saint Petersburg, Russia. pp 354-358. Reprint with corrections in red Introduction Analysis of advanced structures working under extreme heavy loading such as nuclear power plants and piping system should take into account the randomness of loading, geometrical and material parameters. The existing reliability are restricted mostly to the elastic working regime, e.g. allowable local stresses. Development of the limit and shakedown reliability-based analysis and design methods, exploiting potential of the shakedown working regime, is highly needed. In this paper the application of a new algorithm of probabilistic limit and shakedown analysis for shell structures is presented, in which the loading and strength of the material as well as the thickness of the shell are considered as random variables. The reliability analysis problems may be efficiently solved by using a system combining the available FE codes, a deterministic limit and shakedown analysis, and the First and Second Order Reliability Methods (FORM/SORM). Non-linear sensitivity analyses are obtained directly from the solution of the deterministic problem without extra computational costs. 2008 Fachbereich Medizintechnik und Technomathematik OPUS4-217 Konferenzveröffentlichung Tran, Thanh Ngoc, tran@fh-aachen.de; Pham, Phu Tinh, ; Staat, Manfred, m.staat@fh-aachen.de Reliability analysis of shells based on direct plasticity methods Abstracts der CD-Rom Proceedings of the 8th World Congress on Computational Mechanics (WCCM8) and 5th Congress on Computational Methods in Applied Sciences and Engineering (ECCOMAS 2008) 30.06. - 04.07.2008 Venedig, Italien. 2 Seiten Zusammenfassung der Autoren mit graph. Darst. und Literaturverzeichnis 2008 Fachbereich Medizintechnik und Technomathematik OPUS4-75 Wissenschaftlicher Artikel Staat, Manfred, m.staat@fh-aachen.de Basis Reduction for the Shakedown Problem for Bounded Kinematic Hardening Material Limit and shakedown analysis are effective methods for assessing the load carrying capacity of a given structure. The elasto-plastic behavior of the structure subjected to loads varying in a given load domain is characterized by the shakedown load factor, defined as the maximum factor which satisfies the sufficient conditions stated in the corresponding static shakedown theorem. The finite element dicretization of the problem may lead to very large convex optimization. For the effective solution a basis reduction method has been developed that makes use of the special problem structure for perfectly plastic material. The paper proposes a modified basis reduction method for direct application to the two-surface plasticity model of bounded kinematic hardening material. The considered numerical examples show an enlargement of the load carrying capacity due to bounded hardening. 2000 Fachbereich Medizintechnik und Technomathematik OPUS4-73 Wissenschaftlicher Artikel Staat, Manfred, m.staat@fh-aachen.de Direct finite element route for design-by-analysis of pressure components In the new European standard for unfired pressure vessels, EN 13445-3, there are two approaches for carrying out a Design-by-Analysis that cover both the stress categorization method (Annex C) and the direct route method (Annex B) for a check against global plastic deformation and against progressive plastic deformation. This paper presents the direct route in the language of limit and shakedown analysis. This approach leads to an optimization problem. Its solution with Finite Element Analysis is demonstrated for mechanical and thermal actions. One observation from the examples is that the so-called 3f (3Sm) criterion fails to be a reliable check against progressive plastic deformation. Precise conditions are given, which greatly restrict the applicability of the 3f criterion. 2005 Fachbereich Medizintechnik und Technomathematik