TY - CHAP A1 - Höller, Christoph A1 - Parzinger, Michael A1 - Schanda, Ulrich T1 - The Sound Reduction Index of Homogeneous Building Elements according to Annex B of ISO 12354-1 – Discussion and Proposal for Changes T2 - Proceedings of DAS|DAGA 2025, 51st Annual Meeting on Acoustics, March 17-20, 2025, Copenhagen N2 - Annex B of ISO 12354-1:2017 describes a procedure for the calculation of the frequency-dependent sound reduction index of homogeneous building elements such as concrete floors or masonry walls. With the introduction of EN 12354-5:2023 and an upcoming change in DIN 4109-2 regarding the calculation of sound levels due to service equipment, it is anticipated that the practical relevance and usage of Annex B will increase in the future. For this reason, the procedure has recently been investigated by an informal working group of academics from several German universities. It was found that Annex B contains some errors, missing references, and ambiguities in the calculation procedure. Based on these discussions, some changes were proposed to the committee responsible for the standard (CEN/TC 126/WG 2). While the general calculation procedure was left unchanged, the proposed changes focus on the influence of shear deformation, the radiation factor for free waves, a moving average function to limit the variability in the coincidence region, and the calculation examples provided in the annex. This contribution provides an overview of the procedure, presents some background information on the underlying theory, and discusses the proposed changes. Y1 - 2025 SN - 978-3-939296-23-2 U6 - https://doi.org/10.71568/dasdaga2025.147 SP - 312 EP - 315 CY - Berlin ER - TY - CHAP A1 - Bäumler, Georg A1 - Höller, Christoph T1 - Modifying a Wall Transmission Suite to Measure Diffuse Field Sound Absorption Coefficients – A Case Study T2 - Proceedings of DAS|DAGA 2025, 51st Annual Meeting on Acoustics, March 17-20, 2025, Copenhagen N2 - The determination of the diffuse field sound absorption coefficient is carried out in reverberation chambers that comply with the requirements of the corresponding standard, ISO 354. No such chamber exists at OTH Regensburg University of Applied Sciences, but a new wall transmission suite according to ISO 10140 is available. This student project investigates the possibility of using the wall transmission suite to measure absorption coefficients for teaching and research purposes.To assess the suitability of the room, the diffusivity was evaluated using the standard deviation of both the reverberation times and the equivalent continuous sound pressure levels at multiple positions within the room. These results, along with a comparison with expected values for a diffuse sound field, guided the design of reflector panels to introduce diffuse reflections. The implementation features acrylic (PMMA) as the primary material in combination with dense viscoelastic damping sheets, resulting in a low vibration solution. Suspended from the ceiling of the chamber, these improved the diffusivity of the sound field, making the room suitable for absorption measurements across a broad frequency range. Y1 - 2025 SN - 978-3-939296-23-2 U6 - https://doi.org/10.71568/dasdaga2025.291 SP - 1191 EP - 1194 CY - Berlin ER - TY - CHAP A1 - Mühlberger, Thomas A1 - Schoplocher, Paul Dragos A1 - Steffens, Oliver ED - Fouad, Nabil A. T1 - Thermische Gebäudesimulation: aktuelle Anwendungen und Erweiterungen mittels der Finite‐Elemente‐Methode T2 - Bauphysik-Kalender 2025: Simulationen, BIM und KI N2 - Nach einem kurzen historischen Abriss der Entwicklung der Gebäudesimulation wird die aktuell übliche gleichungsbasierte Kompaktmodell-Simulation beschrieben und deren praktische Anwendung aufgezeigt. Dabei wird auf die Bedeutung der Validierung von Simulationstools und auf etablierte Validierungsstandards eingegangen. Gebäudesimulation dient der Optimierung des Bauens in allen Planungsphasen. Mit Praxisbeispielen vom sommerlichen Wärmeschutz bis hin zur Modellierung innovativer Konstruktionen werden unterschiedliche Einsatzbereiche demonstriert. Im zweiten Teil wird die Verwendung der Finite-Elemente-Methode (FEM) für die bauphysikalische Modellierung vorgestellt. Anhand von Beispielen zeigen wir, dass die (rechenzeitintensive) FEM aufgrund einer detaillierteren Modellierung von Geometrie, Strahlung und Konvektion präzisere Simulationsergebnisse liefert. Zum Abschluss werden Wege vorgeschlagen, wie dies zur Erweiterung der schnelleren Kompaktmodell-Simulation eingesetzt werden kann. KW - Energieeffizienz KW - Finite-Elemente-Methode KW - Gebäudesimulation KW - Kompaktmodelle KW - thermische Bauphysik Y1 - 2025 SN - 9783433034514 U6 - https://doi.org/10.1002/9783433612095.ch12 SP - 435 EP - 468 PB - Ernst & Sohn CY - Berlin ER - TY - CHAP A1 - Buchner, Stefan A1 - Wagner, Marcus A1 - Höller, Christoph T1 - Inverse Acoustic Characterization of Rigid Porous Media using Artificial Neural Networks T2 - Proceedings of DAS|DAGA 2025, 51st Annual Meeting on Acoustics, March 17-20, 2025, Copenhagen N2 - Porous sound absorbers can be described by the isotropic Biot model, and its fluid phase can be represented by the Champoux-Allard model. To apply these models to a given absorber material, the five acoustical and the four mechanical material parameters must be known. The direct measurement of these parameters is complex and requires cost-intensive measurement equipment. Current inverse methods to obtain these material parameters solve an optimization problem, trying to fit the absorption or impedance curve of the material model to the impedance tube measurement data. Solving this optimization problem, i.e. finding the global minimum, is not guaranteed in an acceptable amount of time, as the optimization problem possesses a multitude of local minima. This work proposes an alternative, data driven approach using artificial neural networks to obtain the material parameters necessary for the characterization of open porous materials. The approach only requires the results of standard impedance tube measurements. The characterization of rigid- and elastic frame materials has been investigated. The datasets were generated using the rigid and elastic frame models for porous absorbers. The approach shows good results for impedance curves generated by the analytical models, the validation with real-world impedance tube measurement data is currently under investigation. Y1 - 2025 SN - 978-3-939296-23-2 U6 - https://doi.org/10.71568/dasdaga2025.142 SP - 847 EP - 850 CY - Berlin ER -