Dokument-ID Dokumenttyp Autoren/innen Persönliche Herausgeber/innen Haupttitel Abstract Auflage Verlagsort Verlag Herausgeber (Institution) Erscheinungsjahr Titel des übergeordneten Werkes Jahrgang/Band ISBN Veranstaltung Veranstaltungsort Beginndatum der Veranstaltung Enddatum der Veranstaltung Ausgabe/Heft Erste Seite Letzte Seite URN DOI Lizenz Datum der Freischaltung OPUS4-24603 Zeitschriftenartikel Pittner, Andreas; Weiß, D.; Schwenk, Christopher; Rethmeier, Michael Fast temperature field generation for welding simulation and reduction of experimental effort The quality of welding processes is governed by the occurring induced distortions yielding an increase in production costs due to necessary reworking. Especially for more complex specimens, it is difficult to evaluate the optimal configuration of welding sequences in order to minimize the distortion. Even experienced welding operators can solve this task only by trial and error which is time and cost consuming. In modern engineering the application of welding simulation is already known to be able to analyse the heat effects of welding virtually. However, the welding process is governed by complex physical interactions. Thus, recent weld thermal models are based on many simplifications. The state of the art is to apply numerical methods in order to solve the transient heat conduction equation. Therefore, it is not possible to use the real process parameters as input for the mathematical model. The model parameters which allow calculating a temperature field that is in best agreement with the experiments cannot be defined directly but inversely by multiple simulations runs. In case of numerical simulation software based on finite discretization schemes this approach is very time consuming and requires expert users. The weld thermal model contains an initial weakness which has to be adapted by finding an optimal set of model parameters. This process of calibration is often done against few experiments. The range of model validity is limited. An extension can be obtained by performing a calibration against multiple experiments. The focus of the paper is to show a combined modelling technique which provides an efficient solution of the inverse heat conduction problem mentioned above. On the one hand the inverse problem is solved by application of fast weld thermal models which are closed form solutions of the heat conduction equation. In addition, a global optimization algorithm allows an automated calibration of the weld thermal model. This technique is able to provide a temperature field automatically that fits the experimental one with high accuracy within minutes on ordinary office computers. This fast paradigm permits confirming the application of welding simulation in an industrial environment as automotive industry. On the other hand, the initial model weakness is compensated by calibrating the model against multiple experiments. The unknown relationship between model and process parameters is approximated by a neural network. The validity of the model is increased successively and enables to decrease experimental effort, For a test case, it is shown that this approach yields accurate temperature fields within very short amount of time for unknown process parameters as input data to the model contributing to the requirement to construct a substitute system of the real welding process. Oxford Springer International Institute of Welding 2011 Welding in the world 55 09-10 83 90 2016-02-19 OPUS4-18300 Zeitschriftenartikel Pittner, Andreas; Weiß, D.; Schwenk, Christopher; Rethmeier, Michael Methodology to improve applicability of welding simulation The objective of this paper is to demonstrate a new simulation technique which allows fast and automatic generation of temperature fields as input for subsequent thermomechanical welding simulation. The basic idea is to decompose the process model into an empirical part based on neural networks and a phenomenological part that describes the physical phenomena. The strength of this composite modelling approach is the automatic calibration of mathematical models against experimental data without the need for manual interference by an experienced user. As an example for typical applications in laser beam and GMA-laser hybrid welding, it is shown that even 3D heat conduction models of a low complexity can approximate measured temperature fields with a sufficient accuracy. In general, any derivation of model fitting parameters from the real process adds uncertainties to the simulation independent of the complexity of the underlying phenomenological model. The modelling technique presented hybridises empirical and phenomenological models. It reduces the model uncertainties by exploiting additional information which keeps normally hidden in the data measured when the model calibration is performed against few experimental data sets. In contrast, here the optimal model parameter set corresponding to a given process parameter is computed by means of an empirical submodel based on relatively large set of experimental data. The approach allows making a contribution to an efficient compensation of modelling inaccuracies and lack of knowledge about thermophysical material properties or boundary conditions. Two illustrating examples are provided. London Maney Institute of Materials, Minerals and Mining 2008 Science and technology of welding and joining 13 6 496 508 10.1179/136217108X329322 2016-02-19 OPUS4-18290 Beitrag zu einem Sammelband Pittner, Andreas; Weiss, D.; Schwenk, Christopher; Rethmeier, Michael A methodology for the fast temperature field generation for welding simulation Cambridge TWI 2008 Proceedings of the 17th International Conference Computer Technology in Welding and Manufacturing 978-1-903761-07-6 17th International Conference "Computer Technology in Welding and Manufacturing" Cranfield, UK 2008-06-18 2008-06-19 1 12 2016-02-19 OPUS4-16491 Beitrag zu einem Sammelband Schwenk, Christopher; Rethmeier, Michael; Weiss, D. H.K.D.H. Bhadeshia, ; H. Cerjak, ; E. Kozeschnik, Rapid generation of temperature fields for simulation of welding distortions Graz, Austria Technische Universität Graz 2007 Mathematical Modelling of Weld Phenomena 8 978-3-902465-69-6 835 846 2016-02-19 OPUS4-19639 Beitrag zu einem Tagungsband Pittner, Andreas; Weiss, D.; Schwenk, Christopher; Rethmeier, Michael V.I. Makhnenko, Fast generation and prediction of welding temperature fields for multiple experiments The objective of this paper is to demonstrate a new simulation technique which allows the fast and automatic generation to temperature fields based on a combination of empirical and phenomenological modelling techniques. The automatic calibration of the phenomenological model is performed by a multi-variable global optimisation routine which yields the optimal fit between simulated and experimental weld charcteristics without the need for initial model parameters. For exemplary welding processes it is shown that linear 3D heat conduction models can approximate measured temperature fields with a high accuracy. The modelling approach presented comprises the automatic calibration against multiple experiments which permits simulating the temperature field for unknown process parameters. The validation of this composite simulation model is performed for exemplary welding processes and includes the prediction of the fusion line in the cross section and the corresponding thermal cycles. Kiev, Ukraine E.O. Paton Electric Welding Institute of the NAS of Ukraine 2008 Mathematical modelling and information technologies in welding and related processes - 4th International Conference (Proceedings) 4th International Conference - Mathematical modelling and information technologies in welding and related processes Katsiveli, Crimea, Ukraine 2008-05-27 2008-05-30 134 140 2016-02-19 OPUS4-19744 Forschungsbericht Pittner, Andreas; Weiss, D.; Schwenk, Christopher; Rethmeier, Michael Fast temperature field generation for welding simulation and reduction of experimental effort The quality of welding processes is governed by the occurring induced distortions yielding an increase in production costs due to necessary reworking. Especially for more complex specimens it is difficult to evaluate the optimal configuration of welding sequences in order to minimise the distortion. Even experienced welding operators can solve this task only by trial and error which is time and cost consuming. In modern engineering the application of welding simulation is already known to be able to analyse the heat effects of welding virtually. However, the welding process is governed by complex physical interactions. Thus, recent weld thermal models are based on many simplifications. The state of the art is to apply numerical methods in order to solve the transient heat conduction equation. Therefore, it is not possible to use the real process parameters as input for the mathematical model. The model parameters which allow calculating a temperature field that is in best agreement with the experiments cannot be defined directly but inversely by multiple simulations runs. In case of numerical simulation software based on finite discretisation schemes this approach is very time consuming and requires expert users. The weld thermal model contains an initial weakness which has to be adapted by finding an optimal set of model parameters. This process of calibration is often done against few experiments. The range of model validity is limited. An extension can be obtained by performing a calibration against multiple experiments. The focus of the paper is to show a combined modelling technique which provides an efficient solution of the inverse heat conduction problem mentioned above. On the one hand the inverse problem is solved by application of fast weld thermal models which are closed form solutions of the heat conduction equation. In addition, a global optimisation algorithm allows an automated calibration of the weld thermal model. This technique is able to provide a temperature field automatically that fits the experimental one with high accuracy within minutes on ordinary office computers. This fast paradigm permits confirming the application of welding simulation in an industrial environment as automotive industry. On the other hand, the initial model weakness is compensated by calibrating the model against multiple experiments. The unknown relationship between model and process parameters is approximated by a neural network. The validity of the model is increased successively and enables to decrease experimental effort. For a test case it is shown, that this approach yields accurate temperature fields within very short amount of time for unknown process parameters as input data to the model contributing to the requirement to construct a substitute system of the real welding process. Paris International Institute of Welding 2009 IIW Document SC-Auto-32-09 1 11 2016-02-19 OPUS4-20882 Beitrag zu einem Tagungsband Pittner, Andreas; Schwenk, Christopher; Weiß, D.; Rethmeier, Michael Application of a combined modelling technique to reduce experimental effort - a case study for laser-GMA-hybrid welding Saint Petersburg, Russia Saint Petersburg state polytechnic university 2009 VI. International conference "Beam technologies & laser application" VI. International conference "Beam technologies & laser application" Saint Petersburg, Russia 2009-09-23 2009-09-25 97 102 2016-02-19 OPUS4-23154 Beitrag zu einem Sammelband Pittner, Andreas; Schwenk, Christopher; Weiß, D.; Rethmeier, Michael Cerjak, H.; Enzinger, N. An efficient solution of the inverse heat conduction problem for welding simulation Verlag der Technischen Universität Graz 2010 Mathematical modelling of weld phenomena 9 978-3-85125-127-2 761 791 2016-02-19 OPUS4-55428 Zeitschriftenartikel Reuter, T.; Plotzki, David; Borges de Oliveira, F.; Wohlgemuth, F.; Bauer, F.; Ballach, F.; Kimmig, W.; Wagner, G.; Watzl, C.; Weiß, D.; Hausotte, T. Numerical measurement uncertainty evaluation for X-ray computed tomography using simulations - A first approach to build a digital twin The ability of industrial X-ray computed tomography (CT) to scan an object with several internal and external features at once causes increasing adoption in dimensional metrology. In order to evaluate the quality of a measurement value, the task-specific measurement uncertainty has to be determined. Currently, VDI/VDE 2630 part 2.1 gives a guideline to determine the uncertainty of CT measurements experimentally by conducting repeated measurements. This is costly and time-consuming. Thus, the aim is to determine the task-specific measurement uncertainty numerically by simulations (e. g. according to the guide to expression of uncertainty in measurement (GUM) Supplement 1). To achieve that, a digital twin is necessary. This contribution presents a simple first approach how a digital twin can be built. In order to evaluate this approach, a study comparing measurements and simulations of different real CT systems was carried out by determining the differences between the measurement results of the digital twin and of the measurement results of the real-world CT systems. The results have shown a moderate agreement between real and simulated data. To improve on this aspect, a standardized method to characterize CT systems and methods to implement CT parameters into the simulation with sufficient accuracy will be developed. Berlin De Gruyter 2022 tm - Technisches Messen 1 16 10.1515/teme-2022-0025 2022-08-03 OPUS4-19826 Zeitschriftenartikel Pittner, Andreas; Schwenk, Christopher; Rethmeier, Michael; Weiß, D. Automated generation of temperature fields for numerical welding simulation Tokyo, Japan Yosetsu Gakkai 2009 Quarterly journal of the Japan Welding Society 27 2 219 224 2016-02-19 OPUS4-18614 Beitrag zu einem Sammelband Pittner, Andreas; Schwenk, Christopher; Rethmeier, Michael; Weiß, D. Hirata, Yoshinori; Manabu Tanaka, Automated generation of temperature fields for numerical welding simulation Kyoto Japan Welding Society 2008 Proceedings of the 8th International Welding Symposium - Innovations in Welding and Joining for a New Era in Manufacturing 8th International Welding Symposium - Innovations in Welding and Joining for a New Era in Manufacturing Kyoto, Japan 2008-11-16 2008-11-18 158 2016-02-19 OPUS4-57870 Beitrag zu einem Tagungsband Asna Ashari, Parsa; Weiss, D.; Blind, K. Jakobs, K. Fuel-cell Vehicles in Relation to Electric and Internal Combustion Engine Vehicles - An Analysis of Technology Relations based on Publications, Patents, Standards Against the backdrop of the sustainability transition of economies worldwide, decarbonizing road traffic is high on the agenda. This has focused the interest of policymakers and automobile manufacturers on sustainable, zero-emission powertrain technologies. Among these technologies, hydrogen fuel cell (FC) vehicles have a positive climate impact, given that their hydrogen is produced from renewable energy. However, FC vehicles have not yet gained significant market shares. Therefore, based on the technological innovation systems (TIS) approach, this study analyzes how FC vehicles are influenced by EVs and internal combustion engine (ICE) vehicles as their context structures. To operationalize the technology relations between our focal FC-TIS and its context structures, we use the sum of international publications, patents filed at the European Patent Office, and international ISO and IEC standards as indicators for each technology. Our results show that the FC-TIS is dominated by its context structures, especially regarding commercially relevant patents and international standards. Therefore, we conclude that the FC-TIS is in its formative life-cycle phase and identify the need for intensified patenting and standardization in relation to the competing EVs and ICE vehicles. Aachen Verlagshaus Mainz RWTH Aachen 2023 Joint Proceedings EURAS & SIIT 2023 - (Responsible) Standardisation for Smart Systems 978-3-95886-491-7 27th EURAS Annual Standardisation Conference & 12th International Conference on Standardisation and Innovation in Information Technology (SIIT) - (Responsible) Standardisation for Smart Systems Aachen, Germany 28.06.2023 30.06.2023 1 20 2023-07-10