@phdthesis{Diemar2007, author = {Diemar, Andreas}, title = {Simulation des Einsatzh{\"a}rtens und Absch{\"a}tzung der Dauerfestigkeit einsatzgeh{\"a}rteter Bauteile}, doi = {10.25643/bauhaus-universitaet.1109}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20080213-12945}, school = {Bauhaus-Universit{\"a}t Weimar}, year = {2007}, abstract = {Die vorliegende Arbeit besitzt zwei Schwerpunkte. Zum einen wird das Einsatzh{\"a}rten von Bauteilen basierend auf vorhandenen Materialmodellen simuliert. Zum anderen wird ein Konzept zur Absch{\"a}tzung der Dauerfestigkeit einsatzgeh{\"a}rteter Bauteile vorgestellt, in dem wesentliche Ergebnisse der W{\"a}rmebehandlungssimulation als neue Ausgangsgr{\"o}ßen verwendet werden. Damit konnte erstmals ein geschlossenes werkstoffmechanisches Dauerfestigkeitskonzept f{\"u}r einsatzgeh{\"a}rtete Bauteile erarbeitet werden. F{\"u}r die Analyse beliebiger Bauteilgeometrien ist eine Implementation der Materialmodelle in die FEM notwendig. Im Rahmen dieser Arbeit wurde das FE-Programm ABAQUS verwendet. Speziell f{\"u}r dieses FE-Programm wurde innerhalb dieser Arbeit das Subroutine-System ANTRI zur Simulation des Einsatzh{\"a}rtens und Absch{\"a}tzung der Dauerfestigkeit f{\"u}r einsatzgeh{\"a}rtete Bauteile entwickelt. Zur Verifikation des Subroutine-Systems ANTRI wurden experimenteller Ergebnisse aus der Literatur herangezogen. F{\"u}r alle untersuchten Beispiele wurde eine sehr gute {\"U}bereinstimmung zwischen experimentell ermittelten Daten und simulierten Daten festgestellt.}, subject = {W{\"a}rmebehandlung}, language = {de} } @article{IbanezKraus, author = {Ibanez, Stalin and Kraus, Matthias}, title = {A Numerical Approach for Plastic Cross Cross-Sectional Analyses of Steel Members}, series = {ce/papers}, volume = {2021}, journal = {ce/papers}, number = {Volume 4, issue 2-4}, publisher = {Ernst \& Sohn, a Wiley brand}, address = {Berlin}, doi = {10.1002/cepa.1527}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20220112-45622}, pages = {2098 -- 2106}, abstract = {Global structural analyses in civil engineering are usually performed considering linear-elastic material behavior. However, for steel structures, a certain degree of plasticization depending on the member classification may be considered. Corresponding plastic analyses taking material nonlinearities into account are effectively realized using numerical methods. Frequently applied finite elements of two and three-dimensional models evaluate the plasticity at defined nodes using a yield surface, i.e. by a yield condition, hardening rule, and flow rule. Corresponding calculations are connected to a large numerical as well as time-consuming effort and they do not rely on the theoretical background of beam theory, to which the regulations of standards mainly correspond. For that reason, methods using beam elements (one-dimensional) combined with cross-sectional analyses are commonly applied for steel members in terms of plastic zones theories. In these approaches, plasticization is in general assessed by means of axial stress only. In this paper, more precise numerical representation of the combined stress states, i.e. axial and shear stresses, is presented and results of the proposed approach are validated and discussed.}, subject = {Stahlkonstruktion}, language = {en} } @article{StaubachMachacekSkowroneketal.2020, author = {Staubach, Patrick and Machacek, Jan and Skowronek, Josefine and Wichtmann, Torsten}, title = {Vibratory pile driving in water-saturated sand: Back-analysis of model tests using a hydro-mechanically coupled CEL method}, series = {Soils and Foundations}, volume = {2021}, journal = {Soils and Foundations}, number = {Volume 61, Issue 1}, publisher = {Elsevier, Science Direct}, address = {Amsterdam}, doi = {10.1016/j.sandf.2020.11.005}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20210203-43571}, pages = {144 -- 159}, year = {2020}, abstract = {The development of a hydro-mechanically coupled Coupled-Eulerian-Lagrangian (CEL) method and its application to the back-analysisof vibratory pile driving model tests in water-saturated sand is presented. The predicted pile penetration using this approachis in good agreement with the results of the model tests as well as with fully Lagrangian simulations. In terms of pore water pressure, however, the results of the CEL simulation show a slightly worse accordance with the model tests compared to the Lagrangian simulation. Some shortcomings of the hydro-mechanically coupled CEL method in case of frictional contact problems and pore fluids with high bulk modulus are discussed. Lastly, the CEL method is applied to the simulation of vibratory driving of open-profile piles under partially drained conditions to study installation-induced changes in the soil state. It is concluded that the proposed method is capable of realistically reproducing the most important mechanisms in the soil during the driving process despite its addressed shortcomings.}, subject = {Plastische Deformation}, language = {en} }