@article{34000,
abstract = {{Abstract
This paper presents the characterization of the microstructure evolution during flow forming of austenitic stainless steel AISI 304L. Due to plastic deformation of metastable austenitic steel, phase transformation from γ-austenite into α’-martensite occurs. This is initiated by the formation of shear bands as product of the external stresses. By means of coupled microscopic and micromagnetic investigations, a characterization of the microstructure was carried out. In particular, this study shows the distribution of the strain-induced α’-martensite and its influence on material properties like hardness at different depths. The microstructural analyses by means of electron backscattered diffraction (EBSD) technique, evidence a higher amount of α’-martensite (ca. 23 %) close to the outer specimen surface, where the plastic deformation and the direct contact with the forming tool take place. In the middle area (ca. 1.5 mm depth from the outer surface), the portion of transformed α’-martensite drops to 7 % and in the inner surface to 2 %. These results are well correlated with microhardness and micromagnetic measurements at different depths. EBSD and atomic force microscopy (AFM) were used to make a detailed characterization of the topography and degree of deformation of the shear bands. Likewise, the mechanisms of nucleation of α’-martensite were discussed. This research contributes to the development of micromagnetic sensors to monitor the evolution of properties during flow forming. This makes them more suitable for closed-loop property control, which offers possibilities for an application-oriented and more efficient production.}},
author = {{Rozo Vasquez, Julian and Kanagarajah, Hanigah and Arian, Bahman and Kersting, Lukas and Homberg, Werner and Trächtler, Ansgar and Walther, Frank}},
issn = {{2195-8599}},
journal = {{Practical Metallography}},
keywords = {{Metals and Alloys, Mechanics of Materials, Condensed Matter Physics, Electronic, Optical and Magnetic Materials}},
number = {{11}},
pages = {{660--675}},
publisher = {{Walter de Gruyter GmbH}},
title = {{{Coupled microscopic and micromagnetic depth-specific analysis of plastic deformation and phase transformation of metastable austenitic steel AISI 304L by flow forming}}},
doi = {{10.1515/pm-2022-0064}},
volume = {{59}},
year = {{2022}},
}
@article{33999,
abstract = {{The production of complex multi-functional, high-strength parts is becoming increasingly important in the industry. Especially with small batch size, the incremental flow forming processes can be advantageous. The production of parts with complex geometry and locally graded material properties currently depicts a great challenge in the flow forming process. At this point, the usage of closed-loop control for the shape and properties could be a feasible new solution. The overall aim in this project is to establish an intelligent closed-loop control system for the wall thickness as well as the α’-martensite content of AISI 304L-workpieces in a flow forming process. To reach this goal, a novel sensor concept for online measurements of the wall thickness reduction and the martensite content during forming process is proposed. It includes the setup of a modified flow forming machine and the integration of the sensor system in the machine control. Additionally, a simulation model for the flow forming process is presented which describes the forming process with regard to the plastic workpiece deformation, the induced α’-martensite fraction, and the sensor behavior. This model was used for designing a closed-loop process control of the wall thickness reduction that was subsequently realized at the real plant including online measured feedback from the sensor system.}},
author = {{Kersting, Lukas and Arian, Bahman and Vasquez, Julian Rozo and Trächtler, Ansgar and Homberg, Werner and Walther, Frank}},
issn = {{1662-9795}},
journal = {{Key Engineering Materials}},
keywords = {{Mechanical Engineering, Mechanics of Materials, General Materials Science}},
pages = {{862--874}},
publisher = {{Trans Tech Publications, Ltd.}},
title = {{{Innovative Online Measurement and Modelling Approach for Property-Controlled Flow Forming Processes}}},
doi = {{10.4028/p-yp2hj3}},
volume = {{926}},
year = {{2022}},
}
@inproceedings{36563,
author = {{Rozo Vasquez, Julian and Walther, Frank and Arian, Bahman and Homberg, Werner and Kersting, Lukas and Trächtler, Ansgar}},
booktitle = {{Proceedings of the 14th International Conference on Barkhausen Noise and Micromagnetic Testing}},
location = {{Stockholm}},
title = {{{Soft sensor concept for micromagnetic depth-specific analysis of phase transformation during flow forming of AISI 304L steel.}}},
year = {{2022}},
}
@book{36412,
author = {{Kersting, Lukas and Trächtler, Ansgar and Arian, Bahman and Homberg, Werner and Rozo Vasquez, Julian and Walther, Frank}},
isbn = {{978-3-948749-23-1 }},
publisher = {{Diedrich}},
title = {{{Echtzeitfähige Modellierung eines innovativen Drückwalzprozesses für die eigenschaftsgeregelte Herstellung gradierter Bauteile.}}},
year = {{2022}},
}
@article{33338,
author = {{Hein, Maxwell}},
journal = {{Crystals}},
publisher = {{MDPI}},
title = {{{Influence of Physical Vapor Deposition on High-Cycle Fatigue Performance of Additively Manufactured Ti-6Al-7Nb Alloy}}},
doi = {{10.3390/cryst12091190}},
year = {{2022}},
}
@misc{29000,
abstract = {{This thesis aims to provide a bidirectional chatbot solution for the requirement engineering process. The Sonderforschungsbereich (SFB) 901 intends to provide the composition of software service On-the-Fly (OTF). The sub-project (B1) of the SFB 901 project deals with the parameters of service configuration. OTF Computing aims to eradicate the dependency on the requirement engineers for the software development process. However, there is no existing bidirectional chatbot solution that analyses user software requirements and provides viable suggestions to the user regarding their service. Previously, CORDULA chatbot was developed to analyze the software requirements but cannot keep the conversation’s context. The Rasa framework is integrated with the knowledge base to solve the issue, the knowledge base provides domain-specific knowledge to the chatbot. The software description is passed through the natural language understanding process to give consciousness to the chatbot. This process involves various machine learning models, including app family classification, to correctly identify the domain for user OTF service. The statistical models like naïve Bayes, kNN and SVM are compared with transformer models for this classification task. Furthermore, the entities (functional requirements) are also separated from the user description.
The chatbot provides the suggestion of requirements from the preliminary service template with the support of the knowledge base. Furthermore, the generated response is compared with the state-of-the-art DialoGPT transformer model and ChatterBot conversational library. These models are trained over the software development related conversational dataset. All the responses are ranked using the DialoRPT model, and the BLEU score to evaluates the models’ responses. Moreover, the chatbot mod- els are tested with human participants, they used and scored the chatbot responses based on effectiveness, efficiency and satisfaction. The overall response accuracy is also measured by averaging the user approval over the generated responses.}},
author = {{Ahmed, Mobeen}},
title = {{{Knowledge Base Enhanced & User-centric Dialogue Design for OTF Computing}}},
year = {{2022}},
}
@article{32869,
abstract = {{The further development of in-mold-assembly (IMA) technologies for structural hybrid components is of great importance for increasing the economic efficiency and thus the application potential. This paper presents an innovative IMA process concept for the manufacturing of bending loaded hybrid components consisting of two outer metal belts and an inner core structure made of glass mat reinforced thermoplastic (GMT). In this process, the core structure, which is provided with stiffening ribs and functional elements, is formed and joined to two metal belts in one single step. For experimental validation of the concept, the development of a prototypic molding tool and the manufacturing of hybrid beams including process parameters are described. Three-point bending tests and optical measurement technologies are used to characterize the failure behavior and mechanical properties of the produced hybrid beams. It was found that the innovative IMA process enables the manufacturing of hybrid components with high energy absorption and low weight in one step. The mass-specific energy absorption is increased by 693 % compared to pure GMT beams.}},
author = {{Stallmeister, Tim and Tröster, Thomas}},
issn = {{1662-9795}},
journal = {{Key Engineering Materials}},
keywords = {{Mechanical Engineering, Mechanics of Materials, General Materials Science}},
pages = {{1457--1467}},
publisher = {{Trans Tech Publications, Ltd.}},
title = {{{In-Mold-Assembly of Hybrid Bending Structures by Compression Molding}}},
doi = {{10.4028/p-5fxp53}},
volume = {{926}},
year = {{2022}},
}
@inproceedings{39639,
author = {{Finke, Josefine and Horwath, Ilona and Matzner, Tobias and Schulz, Christian}},
booktitle = {{Artificial Intelligence in HCI}},
pages = {{149--160}},
publisher = {{Springer International Publishing}},
title = {{{(De)Coding Social Practice in the Field of XAI: Towards a Co-constructive Framework of Explanations and Understanding Between Lay Users and Algorithmic Systems}}},
doi = {{10.1007/978-3-031-05643-7_10}},
year = {{2022}},
}
@inbook{39638,
author = {{Horwath, Ilona}},
booktitle = {{Inter- und multidisziplinäre Perspektiven der Geschlechterforschung}},
editor = {{Schnegg, Kordula and Tschuggnall, Julia and Voithofer , Caroline and Auer , Manfred}},
pages = {{71--101}},
publisher = {{innsbruck university press}},
title = {{{Algorithmen, KI und soziale Diskriminierung}}},
volume = {{4}},
year = {{2022}},
}
@inbook{39637,
author = {{Horwath, Ilona and Kastein, Mara and Finke, Josefine}},
booktitle = {{Care-Arbeit und Gender in der digitalen Transformation}},
editor = {{Kastein, Mara and Weber, Lena}},
pages = {{119--134}},
publisher = {{Juventa Verlag}},
title = {{{Waschen, Warten, Wege ebnen. Ambivalente Fürsorge und der männliche Heldenmythos in der Feuerwehr}}},
year = {{2022}},
}
@inproceedings{33803,
author = {{Hanses, Hendrik and Horwath, Ilona}},
booktitle = {{Conference proceedings 38th Danubia Adria Symposium on Advances in Experimental Mechanics}},
editor = {{Kourkoulis, Stavros K.}},
isbn = {{978-618-86278-0-2}},
location = {{Poros}},
title = {{{OPERATIONAL AND DEMAND-ORIENTED FIREFIGHTING EQUIPMENT }}},
year = {{2022}},
}
@inproceedings{32871,
author = {{Triebus, Marcel and Ostermann, Moritz and Tröster, Thomas and Horwath, Ilona}},
booktitle = {{Materials in Car Body Engineering - Bad Nauheim}},
location = {{Bad Nauheim}},
title = {{{Advanced Automotive Components by Fiber-Metal-Laminates}}},
year = {{2022}},
}
@inproceedings{44376,
author = {{Tonbul, Güldeniz and Kappler, Julian and Murugan, Saravanakumar and Schoch, Roland and Nowakowski, Michal and Lange, Pia and Bauer, Matthias and Buchmeiser, Michael R.}},
location = {{Edinburgh}},
title = {{{Development of Battery System Based on Na-S and Characterization Using X-ray Absorption Spectroscopy}}},
year = {{2022}},
}
@article{30213,
abstract = {{Requirement changes and cascading effects of change propagation are major sources of inefficiencies in product development and increase the risk of project failure. Proactive change management of requirement changes yields the potential to handle such changes efficiently. A systematic approach is required for proactive change management to assess and reduce the risk of a requirement change with appropriate effort in industrial application. Within the paper at hand, a novel method for Proactive Management of Requirement Changes (ProMaRC) is presented. It is developed in close collaboration with industry experts and evaluated based on workshops, pilot users’ feedback, three industrial case studies from the automotive industry and five development projects from research. To limit the application effort, an automated approach for dependency analysis based on the machine learning technique BERT and semi-automated assessment of change likelihood and impact using a modified PageRank algorithm is developed. Applying the method, the risks of requirement changes are assessed systematically and reduced by means of proactive change measures. Evaluation shows high performance of dependency analysis and confirms the applicability and usefulness of the method. This contribution opens up the research space of proactive risk management for requirement changes which is currently almost unexploited. It enables more efficient product development.}},
author = {{Gräßler, Iris and Oleff, Christian and Preuß, Daniel}},
issn = {{2076-3417}},
journal = {{Applied Sciences}},
keywords = {{Fluid Flow and Transfer Processes, Computer Science Applications, Process Chemistry and Technology, General Engineering, Instrumentation, General Materials Science}},
number = {{4}},
publisher = {{MDPI AG}},
title = {{{Proactive Management of Requirement Changes in the Development of Complex Technical Systems}}},
doi = {{10.3390/app12041874}},
volume = {{12}},
year = {{2022}},
}
@inbook{44462,
author = {{Eckel, Julia}},
booktitle = {{Mimesis Expanded. Die Ausweitung der mimetischen Zone}},
editor = {{Balke, Friedrich and Linseisen, Elisa}},
pages = {{267--294}},
publisher = {{Fink}},
title = {{{Animation und Mimesis. Zur digitalen Expansion bewegtbildlicher Mimesis und ‚animimetischem‘ Denken}}},
year = {{2022}},
}
@article{30228,
abstract = {{Confidence in additive manufacturing technologies is directly related to the predictability of part properties, which is influenced by several factors. To gain confidence, online process monitoring with dedicated and reliable feedback is desirable for every process. In this project, a powder bed monitoring system was developed as a retrofit solution for the EOS P3 laser sintering machines. A high-resolution camera records each layer, which is analyzed by a Region-Based Convolutional Neural Network (Mask R-CNN). Over 2500 images were annotated and classified to train the network in detecting defects in the powder bed at a very high level. Each defect is checked for intersection with exposure areas. To distinguish between acceptable imperfections and critical defects that lead to part rejection, the impact of these imperfections on part properties is investigated.}},
author = {{Klippstein, Sven Helge and Heiny, Florian and Pashikanti,, Nagaraju and Gessler, Monika and Schmid, Hans-Joachim}},
journal = {{JOM - The Journal of The Minerals, Metals & Materials Society (TMS)}},
location = {{Online}},
pages = {{1149–1157}},
publisher = {{Springer}},
title = {{{Powder Spread Process Monitoring in Polymer Laser Sintering and its Influences on Part Properties}}},
doi = {{https://doi.org/10.1007/s11837-021-05042-w }},
volume = {{74}},
year = {{2022}},
}
@inproceedings{33356,
abstract = {{By monitoring the recoating process within polymer laser sintering production, it was shown that multiple powder-spread-flaws can be detected. Those groove-like flaws are expected to be the result of agglomerates jamming between the recoater and the last powder layer. This work is analyzing the interaction between powder-spread-flaws and part properties, showing the influence of the recoating process on the performance of laser sintering parts. Therefore, artificial powder-spread-flaws are applied to the build jobs of tensile test specimens which are measured and analyzed regarding the elongation at break, strength and fracture position. For the characteristics of the flaws, the artificial grooves are varied in depth and width. Furthermore, the position of the flaw is changed form mid part to close to surface areas. It was shown, that several flaws are visible at the part surface, resulting in stress concentration and reduced performance. But there are as well parts with flaw-layers, which are not visible after the build process on the part. Those parts can have significantly reduced mechanical properties as well.}},
author = {{Klippstein, Sven Helge and Schmid, Hans-Joachim}},
booktitle = {{Proceedings of the 33nd Annual International Solid Freeform Fabrication Symposium}},
keywords = {{Selective Sasersintering, Process Monitoring, Powder Spread}},
title = {{{Powder Spread Flaws in Polymer Laser Sintering and its Influences on Mechanical Performance}}},
year = {{2022}},
}
@article{44468,
author = {{Schmidt, Stephan and Gräßer, Melanie and Schmid, Hans-Joachim}},
issn = {{1064-8275}},
journal = {{SIAM Journal on Scientific Computing}},
keywords = {{Applied Mathematics, Computational Mathematics}},
number = {{4}},
pages = {{B1175--B1194}},
publisher = {{Society for Industrial & Applied Mathematics (SIAM)}},
title = {{{A Shape Newton Scheme for Deforming Shells with Application to Capillary Bridges}}},
doi = {{10.1137/20m1389054}},
volume = {{44}},
year = {{2022}},
}
@article{44469,
author = {{Menge, Dennis and Schmid, Hans-Joachim}},
issn = {{1022-1360}},
journal = {{Macromolecular Symposia}},
keywords = {{Materials Chemistry, Polymers and Plastics, Organic Chemistry, Condensed Matter Physics}},
number = {{1}},
publisher = {{Wiley}},
title = {{{Low Temperature Laser Sintering with PA12 and PA6 on a Standard System}}},
doi = {{10.1002/masy.202100397}},
volume = {{404}},
year = {{2022}},
}
@phdthesis{30255,
author = {{Wiens, Eugen}},
isbn = {{978-3-8440-8408-5}},
publisher = {{Shaker}},
title = {{{Innendrückwalzen – Ein innovatives Umformverfahren zur inkrementellen Formgebung von wanddickenkonturierten Rohren mit lokal einstellbaren mechanischen Eigenschaften}}},
year = {{2022}},
}