TY - GEN A1 - Gerold, Stefanie A1 - Buhl, Johannes A1 - Geiger, Sonja M. T1 - How to Enhance Time Wealth? Insights from Changes in Time Use and Working Conditions During the COVID-19 Lockdown in Germany T2 - Social Indicators Research N2 - 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. Y1 - 2023 U6 - https://doi.org/10.1007/s11205-023-03252-0 SN - 1573-0921 VL - 171 SP - 349 EP - 371 ER - TY - GEN A1 - Grüger, Lennart A1 - Fischer, Tim Sebastian A1 - Woll, Ralf A1 - Buhl, Johannes T1 - Absicherung von Risiken beim Prozess des Wire Arc Additive Manufacturing T2 - Industry 4.0 Science KW - Additive Manufacturing KW - Wire Arc Additive Manufacturing KW - Failure Mode and Effects Analysis Y1 - 2024 U6 - https://doi.org/10.30844/I4SD.24.1.63 SN - 2942-6154 VL - 2024 IS - 1 SP - 63 EP - 69 ER - TY - GEN A1 - Grüger, Lennart A1 - Fischer, Tim Sebastian A1 - Woll, Ralf A1 - Buhl, Johannes T1 - Safeguarding Against Risks in the Wire Arc Additive Manufacturing Process T2 - Industry 4.0 Science N2 - 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. KW - additive manufacturing KW - wire arc additive manufacturing KW - failure mode and effects analysis Y1 - 2024 U6 - https://doi.org/10.30844/I4SE.24.1.63 SN - 2942-6170 VL - 2024 IS - 1 SP - 63 EP - 69 ER - TY - GEN A1 - Jensch, Felix A1 - Buhl, Johannes A1 - Laue, Robert A1 - Härtel, Sebastian T1 - Application of the plane-strain-compression-test to determine the local mechanical properties of LPBF-manufactured 316l components T2 - Material Forming: The 26th International ESAFORM Conference on Material Forming, Kraków, Poland, April 19-21, 2023 KW - LPBF-Process, Local Properties, Plane-Strain-Compression-Test Y1 - 2023 U6 - https://doi.org/10.21741/9781644902479-17 VL - 28 SP - 149 EP - 149 ER - TY - RPRT A1 - Grüger, Lennart A1 - Sydow, Benjamin A1 - Woll, Ralf A1 - Buhl, Johannes T1 - 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 N2 - 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. KW - manufacturing factor KW - testing specification KW - laser powder bed fusion KW - wire arc direct energy deposition KW - 316L KW - significance KW - statistical method KW - benchmark geometry Y1 - 2023 UR - https://www.mdpi.com/2075-4701/13/11/1900 U6 - https://doi.org/https://doi.org/10.3390/met13111900 ER - TY - GEN A1 - Alimov, Artem A1 - Härtel, Sebastian A1 - Buhl, Johannes A1 - Gardill, Markus A1 - Knaack, Marcus T1 - Erfassung von Pressen­ver­formungen mit Radarsensoren T2 - wt Werkstattstechnik Y1 - 2023 U6 - https://doi.org/10.37544/1436-4980-2023-10-47 SN - 1436-4980 SN - 1436-5006 VL - 113 IS - 10 SP - 425 EP - 431 ER - TY - GEN A1 - Buhl, Johannes A1 - Härtel, Sebastian A1 - Besong, Lemopi Isidore ED - Mocellin, Katia T1 - Temperature Control of the Two-Point Incremental Forming Process to Achieve Homogeneous Martensite Content Based on Finite Element Simulations T2 - Proceedings of the 14th International Conference on the Technology of Plasticity - Current Trends in the Technology of Plasticity, ICTP 2023 - Volume 1 N2 - 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. Y1 - 2023 SN - 978-3-031-41022-2 SN - 978-3-031-41023-9 U6 - https://doi.org/10.1007/978-3-031-41023-9_74 SN - 2195-4356 SP - 739 EP - 747 PB - Springer CY - Cham ER - TY - GEN A1 - Hussain, G. A1 - Hassan, Malik A1 - Wei, Hongyu A1 - Buhl, Johannes A1 - Xiao, Maohua A1 - Iqbal, Asif A1 - Qayyum, Hamza A1 - Riaz, Asim Ahmed A1 - Muhammad, Riaz A1 - Ostrikov, Kostya T1 - Advances on Incremental forming of composite materials T2 - Alexandria Engineering Journal Y1 - 2023 U6 - https://doi.org/10.1016/j.aej.2023.07.045 SN - 1110-0168 VL - Vol. 79 SP - 308 EP - 336 ER - TY - GEN A1 - Hart-Rawung, Thawin A1 - Horn, Alexander A1 - Buhl, Johannes A1 - Bambach, Markus A1 - Merklein, Marion T1 - A unified model for isothermal and non-isothermal phase transformation in hot stamping of 22MnB5 steel T2 - Journal of Materials Processing Technology Y1 - 2023 U6 - https://doi.org/10.1016/j.jmatprotec.2023.117856 SN - 1873-4774 SN - 0924-0136 VL - 313 ER - TY - CHAP A1 - Israr, Rameez A1 - Buhl, Johannes ED - Khan, Wasim Ahmed T1 - An Introduction to Additive Manufacturing (AM) of Metals and Its Trends in Wire-Arc Additive Manufacturing (WAAM) Simulations T2 - Machine Tools : An Industry 4.0 Perspective Y1 - 2023 U6 - https://doi.org/10.1201/9781003220985 PB - CRC Press CY - Boca Raton ER -