TY - GEN A1 - Jafari, Abbas A1 - Titscher, Thomas A1 - Robens-Radermacher, Annika T1 - Bayem: Implementation and derivation of “variational Bayesian inference for a nonlinear forward model [Chappell et al 2008]“ for arbitrary, user-defined model errors N2 - A python implementation of an analytical variational Bayes algorithm of "Variational Bayesian inference for a nonlinear forward model", Chappell, Michael A., Adrian R. Groves, Brandon Whitcher, and Mark W. Woolrich, IEEE Transactions on Signal Processing 57, no. 1 (2008): 223-236, with an updated free energy equation to correctly capture the log evidence. The algorithm requires a user-defined model error allowing an arbitrary combination of custom forward models and measured data. KW - Implementation KW - Variational Bayesian inference KW - Nonlinear forward model PY - 2025 DO - https://doi.org/10.5281/zenodo.17804665 PB - Zenodo CY - Geneva AN - OPUS4-65268 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Robens-Radermacher, Annika T1 - Modeling the influence of temperature for extrusion based 3d concrete printing from material to structural stability N2 - Abstract: 3D concrete printing (3DCP) aims to revolutionize construction by increasing automation, reducing material usage, and enabling customized designs. Despite its potential, the lack of regulations and reliance on trial-and-error methods result in significant waste and inefficiencies. Reliable models are needed to predict and control the complex printing process with its various influencing factors from material, process, and environment. This study aims to develop a structural model to predict print stability and prevent buckling and material failure in extrusion-based 3D concrete printing (3DCP), with a focus on environmental influences, particularly temperature. The structural build-up of the material is crucial for stability but is influenced by material ingredients, water-binder ratio, and ambient conditions, which vary in real-world projects. It describes the process of cementitious material gaining strength and stability during its early ages due to thixotropy and early hydration. Modeling that, a time- and temperature-dependent model for the evolution of early-age material parameters, such as stiffness, is derived. The model employs the maturity method, using an equivalent time to capture the temperature influence. It is verified using experimental data on stiffness evolution from squeeze flow tests and yield stress evolution measured from rotational rheometer tests. The model parameters are estimated using Bayesian inference, and validation shows good agreement with experimental data for both parameters at the material level. Subsequently, the derived time- and temperature-dependent stiffness model is adapted into a structural simulation using an elastoplastic material law with nonlinear hardening to study the temperature effect on the stability of 3DCP. Layers are activated sequentially based on a pseudo-density approach. The method is illustrated with an example of a printed wall with a width of one layer under varying ambient temperatures. The temperature impact on buckling and material failure during printing is demonstrated and numerically investigated through a sensitivity study. T2 - 95 th Annual Meeting of the International Association of Applied Mathematics and Mechanics (GAMM) CY - Poznan, Poland DA - 07.04.2025 KW - 3D concrete printing KW - Structural build-up KW - Temperature KW - Maturity method KW - Structural simulation PY - 2025 AN - OPUS4-62966 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hüsken, Götz A1 - Strangfeld, Christoph A1 - Robens-Radermacher, Annika A1 - von Werder, Julia A1 - Weigel, Sandra A1 - Mezhov, Alexander T1 - 63. DAfStb-Forschungskolloquium in der BAM - Themenblock 3: Innovative Technologien N2 - Innovationen sind der Treiber des technologischen Fortschritts. Durch die Anwendung innovativer Technologien, Produktionsverfahren und neuer Materialien können Effizienzsteigerungen erzielt werden, die sowohl zu einer Kosten- als auch Materialreduzierung führen können. Gerade vor dem Hintergrund einer nachhaltigen Entwicklung sind Innovationen der Schlüssel zu einem verantwortungsvollen Umgang mit Ressourcen und Rohstoffen. Im Rahmen des 63. DAfStb-Forschungskolloquiums (Tagungsband: DOI 10.26272/opus4-61338) an der BAM wurden innovative Ansätze im Bereich effizienter Fertigungstechnologien und neuer Materialien vorgestellt, die nachfolgend kurz zusammengefasst werden. T2 - 11. Jahrestagung des DAfStb mit 63. Forschungskolloquium der BAM Green Intelligent Building CY - Berlin, Germany DA - 16.10.2024 KW - Additive Fertigung KW - Biorezeptive Oberflächen KW - Biopolymere PY - 2025 SN - 0005-9846 VL - 75 IS - 4 SP - 134 EP - 135 PB - concrete content UG CY - Schermbeck AN - OPUS4-63069 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Robens-Radermacher, Annika T1 - Modellierung und Simulation von 3D Betondruck – Design- und Prozessoptimierung N2 - Der 3D Betondruck ermöglicht die effiziente und ressourcenschonendere Herstellung maßgeschneiderter Betonstrukturen. Trotz des großen Potentials gibt es bisher keine einheitlichen Normen und Standards für den sicheren und robusten 3D Betondruck. Der Beitrag zeigt das Potential numerischer Methoden und Modelle zur effizienten und ressourcenschonenden Design- und Prozessoptimierung des 3D Betondrucks. Dazu werden die aktuellen Forschungsarbeiten im Bereich der Entwicklung robuster und zuverlässiger numerischer Zwillinge, geeigneter Optimierungstools sowie digitaler Workflows diskutiert. T2 - 11. Jahrestagung des DAfStb mit 63. Forschungskolloquium der BAM Green Intelligent Building CY - Berlin, Germany DA - 16.10.2024 KW - 3D Betondruck KW - Design- und Prozessoptimierung KW - Modellierung KW - Simulation PY - 2024 AN - OPUS4-61575 LA - mul AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -