@misc{AbasAlkahtaniKhalidetal., author = {Abas, Muhammad and Alkahtani, Mohammed and Khalid, Qazi Salman and Hussain, Ghulam and Abidi, Mustufa Haider and Buhl, Johannes}, title = {Parametric Study and Optimization of End-Milling Operation of AISI 1522H Steel Using Definitive Screening Design and Multi-Criteria Decision-Making Approach}, series = {Materials}, volume = {15}, journal = {Materials}, number = {12}, issn = {1996-1944}, doi = {10.3390/ma15124086}, language = {en} } @misc{BesongBuhlBambach, author = {Besong, Lemopi Isidore and Buhl, Johannes and Bambach, Markus}, title = {Increasing formability in hole-flanging through the use of punch rotation based on temperature and strain rate dependent forming limit curves}, series = {International Journal of Material Forming}, volume = {15}, journal = {International Journal of Material Forming}, number = {3}, issn = {1960-6214}, doi = {10.1007/s12289-022-01684-6}, pages = {1 -- 21}, language = {en} } @misc{IsrarBuhlHaerteletal., author = {Israr, Rameez and Buhl, Johannes and H{\"a}rtel, Sebastian and Bambach, Markus}, title = {Reinforcement of Tooling Using Residual Stresses Generated by Cladding by Arc Welding}, series = {Metals}, volume = {12}, journal = {Metals}, number = {6}, issn = {2075-4701}, doi = {10.3390/met12060984}, pages = {30}, abstract = {Cladding is typically used to protect components from wear and corrosion while also improving the aesthetic value and reliability of the substrate. The cladding process induces significant residual stresses due to the temperature difference between the substrate and the clad layer. However, these residual stresses could be effectively utilized by modifying processes and geometrical parameters. This paper introduces a novel methodology for using the weld-cladding process as a cost-effective alternative to various existing reinforcement techniques. The numerical analyses are performed to maximize the reinforcement of a cylindrical tool. The investigation of how the weld cladding develops compressive stresses on the specimen in response to a change in the weld beads and the welding sequence is presented. For the benchmark shape, experimental verification of the numerical model is performed. The influence of the distance between the weld beads and the effect of the tool diameter is numerically investigated. Furthermore, the variation in compressive stresses due to temperature fluctuations during the extrusion process has been evaluated. The results showed that adequate compressive stresses are generated on the welded parts through the cladding process after cooling. More compressive stresses are induced in the tool as the cross-section of the weld bead is increased. Furthermore, keeping a gap between the adjacent beads improves tool reinforcement. Hence, the targeted reinforcement of the substrate can be achieved by optimizing the welding sequence and process parameters.}, language = {en} } @misc{SydowJhanjiHaelsigetal., author = {Sydow, Benjamin and Jhanji, Avantika and H{\"a}lsig, Andr{\´e} and Buhl, Johannes and H{\"a}rtel, Sebastian}, title = {The Benefit of the Process Combination of Wire Arc Additive Manufacturing (WAAM) and Forming—A Numerical and Experimental Study}, series = {Metals}, volume = {12}, journal = {Metals}, number = {6}, issn = {2075-4701}, doi = {10.3390/met12060988}, pages = {13}, language = {en} } @misc{EmdadiBolzBuhletal., author = {Emdadi, Aliakbar and Bolz, Sebastian and Buhl, Johannes and Weiß, Sabine and Bambach, Markus}, title = {Laser Powder Bed Fusion Additive Manufacturing of Fe3Al-1.5Ta Iron Aluminide with Strengthening Laves Phase}, series = {Metals}, volume = {12}, journal = {Metals}, number = {6}, issn = {2075-4701}, doi = {10.3390/met12060997}, language = {en} } @misc{ErtugrulHaelsigHenseletal., author = {Ertugrul, G{\"o}khan and H{\"a}lsig, Andre and Hensel, Jonas and Buhl, Johannes and H{\"a}rtel, Sebastian}, title = {Efficient Multi-Material and High Deposition Coating including Additive Manufacturing by Tandem Plasma Transferred Arc Welding for Functionally Graded Structures}, series = {Metals}, volume = {12}, journal = {Metals}, number = {8}, issn = {2075-4701}, doi = {10.3390/met12081336}, pages = {1 -- 17}, language = {en} } @misc{OmairAlkahtaniAyazetal., author = {Omair, Muhammad and Alkahtani, Mohammed and Ayaz, Kashif and Hussain, Ghulam and Buhl, Johannes}, title = {Supply Chain Modelling of the Automobile Multi-Stage Production Considering Circular Economy by Waste Management Using Recycling and Reworking Operations}, series = {Sustainability}, volume = {14}, journal = {Sustainability}, number = {22}, issn = {2071-1050}, doi = {10.3390/su142215428}, abstract = {The supply chain management plays a crucial role in delivering products from a supplier, through the manufacturer, distributors, and retailers to the targeted customers. The lifecycle of the products can be ended at any stage due to imperfect quality or waste, which are typically not managed well for a good price. This product's life can be extended and increased with the use of the circular economy for the value addition processes which turn the waste into byproducts, which can be sold with maximum profit. The automobile industry is associated with various other small industries and is very significant for the economy at the local, national, and international levels. However, the industry also requires sustainable development in its supply chain management, gained by introducing the circular economy concept to manage and reduce the generated waste. The consumption of carbon fiber-reinforced composites (CFRCs) in the manufacturing of numerous automotive parts has acquired immense attention this decade, but the process also generates imperfect products (waste). The proposed model is based on a mathematical formulation to manage imperfect production by reworking and recycling, where the former is required to re-add value to the proportion of the rejected parts, and the latter is to recycle the remaining scrap into useful products by using a circular economy. The outsourcing operation is also added to provide an optimal level of inventory and lot sizing for minimizing the total cost of the supply chain management. Data from the automobile part industry are tested to provide the practical implications of the proposed SCM mathematical model. Sensitivity analysis is performed to understand the significance level of the individual parameters affecting the objective function, i.e., the total cost of the SCM. The results show a meaningful insight for the managers to obtain the benefits of the circular economy in multi-stage automobile part production for sustainable and resilient supply chain management.}, language = {en} } @misc{HussainAlkahtaniAlsultanetal., author = {Hussain, Ghulam and Alkahtani, Mohammed and Alsultan, Marwan and Buhl, Johannes and Gupta, Munish Kumar}, title = {Chip formation, cutting temperature and forces measurements in hard turning of Gcr15 under the influence of PcBN chamfering parameters}, series = {Measurement}, volume = {Vol. 204}, journal = {Measurement}, issn = {1873-412X}, doi = {10.1016/j.measurement.2022.112130}, language = {en} } @misc{HirtlerUensalBuhletal., author = {Hirtler, Markus and {\"U}nsal, Ismail and Buhl, Johannes and Bambach, Markus}, title = {Investigation of quench hardening behavior of directed energy deposited 22MnB5 steel for local reinforcement of hot stamping parts}, series = {CIRP Journal of Manufacturing Science and Technology}, volume = {Vol. 39}, journal = {CIRP Journal of Manufacturing Science and Technology}, issn = {1878-0016}, doi = {10.1016/j.cirpj.2022.08.003}, pages = {223 -- 231}, language = {en} } @misc{HartRawungBuhlHaerteletal., author = {Hart-Rawung, Thawin and Buhl, Johannes and H{\"a}rtel, Sebastian and Bambach, Markus}, title = {Intelligent Iterative Experimental Design to Achieve Maximum Model Quality for Phase Change of 22MnB5}, series = {Key Engineering Materials}, volume = {926}, journal = {Key Engineering Materials}, publisher = {Verlag Trans Tech Publications Ltd}, doi = {https://doi.org/10.4028/p-0cnty5}, pages = {2031 -- 2039}, language = {en} } @misc{BesongBuhlHaerteletal., author = {Besong, Lemopi Isidore and Buhl, Johannes and H{\"a}rtel, Sebastian and Bambach, Markus}, title = {Increasing the Forming Limits in Hole Flanging of Dual-Phase (DP) 1000 Steel Using Punch Rotation}, series = {Key Engineering Materials}, volume = {Vol. 926}, journal = {Key Engineering Materials}, issn = {1662-9795}, doi = {10.4028/p-06y8un}, pages = {717 -- 723}, language = {en} } @misc{AfzalBuhl, author = {Afzal, Muhammad Junaid and Buhl, Johannes}, title = {Numerical Study to Promote the Residual Stresses Development during ISF Process with Improvement in Two Point Incremental Die Forming}, series = {Key Engineering Materials}, volume = {Vol. 926}, journal = {Key Engineering Materials}, issn = {1662-9795}, pages = {752 -- 759}, language = {en} } @techreport{BuhlButzWesseletal., author = {Buhl, Johannes and Butz, Alexander and Wessel, Alexander and Morand, Lukas}, title = {Intelligente Werkstoffpr{\"u}fung mit automatisierter Versuchsplanung und Modellidentifikation}, publisher = {Euro{\"a}ische Forschungsgesellschaft f{\"u}r Blechverarbeitung}, address = {Hannover}, isbn = {978-3-86776-639-5}, pages = {78, XX}, language = {de} } @misc{GeroldBuhlGeiger, author = {Gerold, Stefanie and Buhl, Johannes and Geiger, Sonja M.}, title = {How to Enhance Time Wealth? Insights from Changes in Time Use and Working Conditions During the COVID-19 Lockdown in Germany}, series = {Social Indicators Research}, volume = {171}, journal = {Social Indicators Research}, issn = {1573-0921}, doi = {10.1007/s11205-023-03252-0}, pages = {349 -- 371}, abstract = {This paper investigates the changes in time use, working conditions and subjective time wealth during the COVID-19 pandemic in Germany. Our analysis draws on panel data collected before and during the first lockdown among 786 employees. It employs a recently developed scale on time wealth which has been suggested as a comprehensive measure to capture the subjective experience of time. We provide separate analyses according to gender and essential occupation. First-difference regressions are applied to examine how changes in time use and changes in working conditions during the lockdown affected subjective time wealth. Our results show a general growth in time wealth during the lockdown which is, among other factors, driven by a decline in work hours and an increase in sleep duration. We also find positive effects on time wealth from decreased time pressure at work, more autonomy in organising one's working day, and an improved reconciliation of work and private life. This study contributes to existing research by identifying key aspects how to improve time wealth among employees.}, language = {en} } @misc{GruegerFischerWolletal., author = {Gr{\"u}ger, Lennart and Fischer, Tim Sebastian and Woll, Ralf and Buhl, Johannes}, title = {Absicherung von Risiken beim Prozess des Wire Arc Additive Manufacturing}, series = {Industry 4.0 Science}, volume = {2024}, journal = {Industry 4.0 Science}, number = {1}, issn = {2942-6154}, doi = {10.30844/I4SD.24.1.63}, pages = {63 -- 69}, language = {de} } @misc{GruegerFischerWolletal., author = {Gr{\"u}ger, Lennart and Fischer, Tim Sebastian and Woll, Ralf and Buhl, Johannes}, title = {Safeguarding Against Risks in the Wire Arc Additive Manufacturing Process}, series = {Industry 4.0 Science}, volume = {2024}, journal = {Industry 4.0 Science}, number = {1}, issn = {2942-6170}, doi = {10.30844/I4SE.24.1.63}, pages = {63 -- 69}, abstract = {In this article, the potential risks in wire arc additive manufacturing are analyzed using failure mode and effects analysis. To achieve this, 186 possible causes of risk were analyzed and the five most critical risks were discussed in detail. Four significant risk factors were identified in the construction process. The fifth risk relates to the shielding gas flow. This is only one influencing factor among the welding parameters, which have strong interactions with each other. Therefore, their relationships should be analyzed on the basis of numerous tests.}, language = {en} } @misc{JenschBuhlLaueetal., author = {Jensch, Felix and Buhl, Johannes and Laue, Robert and H{\"a}rtel, Sebastian}, title = {Application of the plane-strain-compression-test to determine the local mechanical properties of LPBF-manufactured 316l components}, series = {Material Forming: The 26th International ESAFORM Conference on Material Forming, Krak{\´o}w, Poland, April 19-21, 2023}, volume = {28}, journal = {Material Forming: The 26th International ESAFORM Conference on Material Forming, Krak{\´o}w, Poland, April 19-21, 2023}, doi = {10.21741/9781644902479-17}, pages = {149 -- 149}, language = {en} } @techreport{GruegerSydowWolletal., author = {Gr{\"u}ger, Lennart and Sydow, Benjamin and Woll, Ralf and Buhl, Johannes}, title = {Design of a Cost-Effective and Statistically Validated Test Specification with Selected Machine Elements to Evaluate the Influence of the Manufacturing Process with a Focus on Additive Manufacturing}, doi = {https://doi.org/10.3390/met13111900}, pages = {49}, abstract = {Due to their versatile advantages, the use of additively manufactured components is growing. In addition, new additive manufacturing processes are constantly being developed, so that a wide range of printing processes are now available for metal. Despite the same starting material, the microstructure and thus also the final mechanical properties differ greatly compared to conventional processes. In most cases, only direction-dependent characteristic values from the uniaxial tension are used to qualify a printing process before it is used. The literature, on the other hand, demonstrates that the results are not transferable to other loading conditions. In this work, several engineering tests were integrated into a single test specimen so that they can be determined on the same specimen. The test specimen can be used to test tooth root strength, bending strength, notched bar impact energy, and thread strength depending on the mounting direction, thus representing industrial loading cases. In this study, test specimens were fabricated by conventional manufacturing (machining), L-PBF (Laser Powder Bed Fusion), and WA-DED (Wire Arc Direct Energy Deposition), and the results were compared using statistical methods. Factors to capture manufacturing influence and buildup direction were statistically validated on 316L. The work shows a benchmark with a typical initial microstructure of rolled and milled material, L-PBF, and WA-DED parts on loads close to the application and thus simplifies an industry-oriented evaluation of a new manufacturing process.}, language = {en} } @misc{AlimovHaertelBuhletal., author = {Alimov, Artem and H{\"a}rtel, Sebastian and Buhl, Johannes and Gardill, Markus and Knaack, Marcus}, title = {Erfassung von Pressen­ver­formungen mit Radarsensoren}, series = {wt Werkstattstechnik}, volume = {113}, journal = {wt Werkstattstechnik}, number = {10}, issn = {1436-4980}, doi = {10.37544/1436-4980-2023-10-47}, pages = {425 -- 431}, language = {de} } @misc{BuhlHaertelBesong, author = {Buhl, Johannes and H{\"a}rtel, Sebastian and Besong, Lemopi Isidore}, title = {Temperature Control of the Two-Point Incremental Forming Process to Achieve Homogeneous Martensite Content Based on Finite Element Simulations}, series = {Proceedings of the 14th International Conference on the Technology of Plasticity - Current Trends in the Technology of Plasticity, ICTP 2023 - Volume 1}, journal = {Proceedings of the 14th International Conference on the Technology of Plasticity - Current Trends in the Technology of Plasticity, ICTP 2023 - Volume 1}, editor = {Mocellin, Katia}, publisher = {Springer}, address = {Cham}, isbn = {978-3-031-41022-2}, issn = {2195-4356}, doi = {10.1007/978-3-031-41023-9_74}, pages = {739 -- 747}, abstract = {Deformation-induced martensite has been observed in the incremental sheet forming of metastable austenitic stainless steels (MASS). The presence of martensite improves the characteristics of the springs. Martensite transformation usually occurs at low temperatures (<70 ℃). Depending on the tool speed, incremental forming of disk springs requires between 3 to 5 min. The forming time needs to be short to increase the process output in industrial settings. However, accelerating the process leads to high temperatures above the martensite transformation temperature that suppress martensite formation, necessitating temperature control during forming. It is suggested to enhance the martensite content of the blank by cooling during the forming operation. In this contribution, two-point incremental sheet forming is conducted to determine the influence of process temperature on the phase content of MASS disk springs. A temperature-dependent phase change material model that includes the strain rate effect is implemented in finite element (FE) simulations to predict the martensite content. FE simulations are performed to investigate the convection coefficients and cooling time leading to process temperatures below 70 ℃. The framework can be used to control and speed up the incremental forming of disk springs while maintaining a high martensite content.}, language = {en} }