TY - JOUR A1 - Müller, Philipp A1 - Miccoli, Lorenzo A1 - Fontana, Patrick A1 - Ziegert, C. T1 - Development of partial safety factors for earth block masonry N2 - The main aim of the research was the development of a first valid database for material parameters of earth block masonry (EBM) with particular regard to statistical characteristics. A solid database is needed for the determination of the materials partial safety factor. Therefore, compressive strength tests were carried out with two types of earth blocks and two types of prefabricated earth mortar. The evaluation has shown that the mean variation of the compressive strength was remarkably less than expected, which indicates high quality standards of the components earth block and mortar with regard to industrial production. Using the reliability method, a partial safety factor for EBM subjected to compression was determined on the basis of these test results. The findings have shown that a common calculation method for EBM based on partial safety factors following the valid masonry construction standard is feasible. KW - Partial safety factor KW - Earth block masonry (EBM) KW - Reliability KW - Compressive strength PY - 2017 DO - https://doi.org/10.1617/s11527-016-0902-9 SN - 1871-6873 SN - 1359-5997 VL - 50 IS - 1 SP - 1 EP - 14 PB - Springer AN - OPUS4-38937 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Müller, Philipp A1 - Unger, Jörg F. T1 - Waves in inhomogeneous meshes N2 - Elastic waves in inhomogeneous meshes avoiding numerical artifacts Elastic waves in solids resulting from damage processes, e.g. microcracking are used to monitor the integrity of structures. The numerical modelling of these acoustic Emission processes is hindered by the different scales involved. Crack opening is a fast process and the size of the damaged zone is small, leading to small time steps and fine meshes in a numerical finite element simulation. On the other hand the relevant wave Propagation takes place on a much larger spatial scale, e.g covering the distance between Emission source and sensor. To avoid numerical oscillations, the mesh size at the emission source has to be coupled to its time scale. Using higher order spectral elements can be beneficial with respect to the needed number of degrees of freedom. To make the computation of an acoustic emission process feasible one is lead to coarsening the mesh for larger distances to the source. Solution components with a higher frequency will be reflected at mesh density steps. The mesh coarsening has to be done in a way to avoid or minimize this kind of reflections. To get more insight into the propagation characteristics of the numerical solution, dispersion curves are calculated for different element types assuming a structured mesh with constant element size. Coupling two meshes with different mesh densities will then lead to frequency dependent reflections at the boundary similar to the coupling of different materials. The starting mesh density is dictated by the acoustic emission source time scale. The largest allowable mesh size needs to resolve the components of propagating signal with the highest frequency, smallest wavelength which is given by the bandwidth of the sensor. Still coarser meshes may be used when high frequency components are propagated by a different method. T2 - COMPDYN 2019 CY - Crete, Greece DA - 24.06.2019 KW - FEM KW - Waves KW - Dispersion PY - 2019 AN - OPUS4-48582 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - RPRT A1 - Seifert, Lando A1 - Philipp, Markus A1 - Ebell, Gino A1 - Moersch, Jörg A1 - Müller, Thoralf T1 - Final report on WIPANO research project - A new test method for evaluating prestressing steels' susceptibility to stress corrosion cracking N2 - For the safety of prestressed concrete structures, a test of prestressing steel products for hydrogen-induced stress corrosion cracking is mandatory. The current standardized test methods according to DIN EN ISO 15630-3 have proven deficiencies concerning the reproducibility of the results and thus make it difficult to assess the susceptibility clearly. The WIPANO research project funded by BMWK aimed to improve the test method regarding reproducibility and reliability of results. The project created constant and reproducible test conditions by modifying material, electrolyte, and process parameters. This allowed a clear differentiation between good and bad products. As part of the project, a round robin test was initiated to confirm the applicability and reproducibility of the new test method. The new test method was evaluated for its applicability to the prestressing steel product wire. A draft standard with a proposed conformity criterion for these products was submitted to the responsible ISO committee for approval. According to the current feedback from the committee, the draft standard will be included in the informative annex of the testing standard, which could pave the way for mirroring at European and national standardization levels. KW - Prestressing steels KW - ISO 15630-3 KW - Hydrogen-induced stress corrosion cracking KW - Brittle fracture PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-581269 DO - https://doi.org/10.26272/opus4-58126 N1 - Funding source: Federal Ministry of Economic Affairs and Climate Action (BMWK), 11019 Berlin; FKZ: 03TNH019A/B/D SP - 1 EP - 106 PB - Bundesanstalt für Materialforschung und -prüfung (BAM) CY - Berlin AN - OPUS4-58126 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - RPRT A1 - Seifert, Lando A1 - Philipp, M. A1 - Ebell, Gino A1 - Moersch, J. A1 - Müller, Thoralf T1 - Gemeinsamer Schlussbericht zum Forschungsvorhaben - Entwicklung eines neuen Prüfverfahrens zur Beurteilung der Spannungsrisskorrosionsempfindlichkeit von Spannstählen für den Spannbetonbau N2 - Für die Sicherheit von Spannbetonbauwerken ist eine Empfindlichkeitsprüfung von Spannstahlprodukten gegenüber der wasserstoffinduzierten Spannungsrisskorrosion zwingend erforderlich. Die derzeitig normativ festgelegten Prüfmethoden nach DIN EN ISO 15630-3 zeigen nachweislich Schwächen hinsichtlich der Reproduzierbarkeit der Ergebnisse und erschweren damit die eindeutige Bewertung der Empfindlichkeit. Ziel des Forschungsvorhabens der Förderinitiative WIPANO des BMWK war es, die Prüfmethode hinsichtlich der Reproduzierbarkeit und Aussagesicherheit zu verbessern. Im Projekt wurden durch materialseitige, elektrolytische und verfahrenstechnische Parameteränderungen konstante und reproduzierbare Prüfbedingungen geschaffen. Dies ermöglichte eine eindeutige Differenzierung zwischen Gut- und Schlechtprodukten. Innerhalb des Projekts wurde ein Ringversuch initiiert, welcher die Anwendbarkeit und Reproduzierbarkeit der neuen Prüfmethode bestätigte. Das neue Prüfverfahren wurde hinsichtlich der Anwendbarkeit für das Spannstahlerzeugnis Draht evaluiert. Ein entsprechender Normentwurf mit einem Vorschlag für ein Konformitätskriterium dieser Erzeugnisse wurde dem zuständigen ISO-Gremium präsentiert und zur Abstimmung überlassen. Nach aktueller Rückmeldung seitens des Gremiums wird der Normentwurf den Eingang in den informativen Anhang der Prüfnorm finden, dies könnte den Weg für eine Spiegelung auf europäischer und nationaler Normungsebene ebnen. KW - Spannstahl KW - Spannungsrisskorrosion KW - ISO 15630-3 KW - Wasserstoff KW - Permeationsmessung KW - WIPANO PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-577922 DO - https://doi.org/10.26272/opus4-57792 SP - 1 EP - 106 PB - Bundesanstalt für Materialforschung und -prüfung (BAM) CY - Berlin AN - OPUS4-57792 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -