TY - CONF A1 - Javaheri, E. A1 - Pittner, Andreas A1 - Graf, B. A1 - Rethmeier, Michael T1 - Instrumented indentation technique and its application for the determination of local material properties of welded steel structures N2 - The determination of mechanical properties of welded Steel structures such as strength or ductility is a subject of high interest for the majority of Companies in the area of metal Processing. The material Parameters can be obtained by performing the tensile test on the samples made from a part of a component. In some cases, it is highly expensive to produce the tensile specimens especially from the weld metal, which contains different type of microstructure such as weld seam or heat affected zone in an extremely small area. Therefore, a method is described in this paper to determine the material Parameters of high strength Steel structures and welded joints locally and without any additional effort to perform the tensile test. In this method, instrumented indentation technique (IIT), an indenter is pushed on the flat surface of a specimen in a certain period of time and simultaneously the applied force and the corresponding indentation path are measured. The data related to the force-indentation diagram is given as input to an artificial neural network (ANN) to obtain the material Parameters. The ANN can be trained by generating the large qualitative data sets with numerical Simulation of the IIT procedure. The Simulation must be run several times with the different material model parameter sets to generate the numerous force-indentation diagrams as the inputs of ANN. Then, the trained ANN is validated by performing the IIT on the welded joints and comparing the obtained material Parameters from ANN with the tensile test. Consequently, the mechanical properties of welded joints can be determined by performing the IIT and evaluating the resulting data by the ANN. T2 - 39. Assistentenseminar CY - Eupen, Germany DA - 12.09.2018 KW - Steel PY - 2019 SN - 978-396144-070-2 SP - 146 EP - 152 PB - DVS Media GmbH AN - OPUS4-51317 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schaumann, P. A1 - Schürmann, K. A1 - Pittner, Andreas A1 - Rethmeier, Michael T1 - Prediction of the Initial Fatigue Crack Location of Automatically Welded Tubular Joints for Jacket Support Structures N2 - To increase the competitiveness of jacket substructures compared to monopiles a changeover from an individual towards a serial jacket production based on automated manufactured tubular joints com-bined with standardized pipes has to be achieved. Therefore, this paper addresses fatigue tests of automatical-ly welded tubular X-joints focusing on the location of the technical fatigue crack. For this X-joint, the detect-ed location of the technical crack is then compared to numerical investigations predicting the most fatigue prone notch considering the structural stress approach as well as the notch stress approach. Additionally, the fatigue prone hot spot according to both approaches is compared for a typical offshore jacket double-K-joint to emphasize the significance of the presented outcomes for the existing offshore structures. Besides, the welding process of the automated manufactured tubular X-joints is presented. T2 - 7th International Conference on Structural Engineering, Mechanics and Computation (SEMC) CY - Cape Town, SOUTH AFRICA DA - 02.09.2019 KW - Lightweight Design KW - Jacket Support Structures KW - Arc Welding Automation KW - Fatigue KW - Offshore Wind PY - 2019 SN - 978-1-138-38696-9 U6 - https://doi.org/10.1201/9780429426506-100 VL - 2019 SP - 575 EP - 580 AN - OPUS4-51847 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schaumann, P. A1 - Schürmann, K. A1 - Pittner, Andreas A1 - Rethmeier, Michael T1 - Automatically Welded Tubular X-Joints - Welding Procedure and Prediction of the Technical Fatigue Crack Location N2 - To increase the competitiveness of jacket substructures compared to monopiles a changeover from an individual towards a serial jacket production based on automated manufactured tubular joints combined with standardized pipes has to be achieved. Therefore, this paper ad-dresses the welding process of automated manufactured tubular X-joints. Additionally, fatigue tests of the automatically welded tubular joints are presented focusing on the location of the technical fatigue crack. The detected location of the technical crack is compared to numerical investigations predicting the most fatigue prone notch con-sidering the structural stress approach as well as the notch stress ap-proach. T2 - 29th International Ocean and Polar Engineering Conference CY - Honolulu, Hawaii, USA DA - 16.06.2019 KW - Notch stress approach KW - Tubular X-joints KW - Automated manufacturing KW - Fatigue tests KW - Structural stress approach PY - 2019 SN - 978-1-880653-85-2 SP - 4098 EP - 4105 AN - OPUS4-51848 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schaumann, P. A1 - Schürmann, K. A1 - Pittner, Andreas A1 - Rethmeier, Michael T1 - Automatically Welded Tubular X Joints for Jacket Substructures – Prediction of the Technical Fatigue Crack Location N2 - To increase the competitiveness of jacket substructures compared to monopiles a changeover from an individual towards a serial jacket production based on automated manufactured tubular joints combined with standardized pipes has to be achieved. Therefore, this paper addresses fatigue tests of automatically welded tubular X-joints focusing on the location of the technical fatigue crack. The detected location of the technical crack is compared to numerical investigations predicting the most fatigue prone notch considering the structural stress approach as well as the notch stress approach. Besides, the welding process of the automated manufactured tubular X-joints is presented. T2 - Nordic Steel 2019 CY - Copenhagen, Denmark DA - 18.09.2019 KW - Automated arc welding KW - Fatigue tests KW - Tubular X-joints KW - Technical crack detection KW - Local fatigue approaches PY - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-518490 VL - 3 IS - 3-4 SP - 823 EP - 828 PB - Wiley-VCH Verlag GmbH on behalf of Ernst & Sohn Verlag für Architektur und technische Wissenschaften GmbH & Co. KG CY - Berlin AN - OPUS4-51849 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -