07 Fakultät Konstruktions-, Produktions- und Fahrzeugtechnik
Permanent URI for this collectionhttps://elib.uni-stuttgart.de/handle/11682/8
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Item Open Access Driving profiles of light commercial vehicles of craftsmen and the potential of battery electric vehicles when charging on company premises(2024) Heilmann, Oliver; Bocho, Britta; Frieß, Alexander; Cortès, Sven; Schrade, Ulrich; Casal Kulzer, André; Schlick, MichaelThis paper examines the extent to which it is possible to replace conventional light commercial vehicles in the heating, ventilation and air conditioning and plumbing trade with battery electric vehicles with an unchanged usage profile. GPS trackers are used to record the position data of 22 craft vehicles with combustion engines from eleven companies over the duration of one working week. Within this paper, various assumptions (battery capacity and average consumption) are made for battery electric vehicles and the charging power on the company premises. The potential of battery electric vehicles is evaluated based on the assumption that they are charged only on company premises. Using the collected data and the assumptions made, theoretical state of charge curves are calculated for the vehicles. The driving profiles of the individual vehicles differ greatly, and the suitability of battery electric vehicles should be considered individually. Battery capacity, vehicle energy consumption and charging power at the company have a substantial influence on the suitability of battery electric vehicles. Furthermore, there are differences between vehicles that can charge on the company premises at night and those that cannot or can only do so on some days.Item Open Access Generation of mechanical characteristics in workpiece subsurface layers through milling(2024) Storchak, Michael; Hlembotska, Larysa; Melnyk, OleksandrThe generation of mechanical characteristics in workpiece subsurface layers as a result of the cutting process has a predominant influence on the performance properties of machined parts. The effect of the end milling process on the mechanical characteristics of the machined subsurface layers was evaluated using nondestructive methods: instrumented nanoindentation and sclerometry (scratching). In this paper, the influence of one of the common processes of materials processing by cutting-the process of end tool milling-on the generation of mechanical characteristics of workpiece machined subsurface layers is studied. The effect of the end milling process on the character of mechanical property formation was evaluated through the coincidence of the cutting process energy characteristics with the mechanical characteristics of the machined subsurface layers. The total cutting power and cutting work in the tertiary cutting zone area were used as energy characteristics of the end milling process. The modes of the end milling process are considered as the main parameters affecting these energy characteristics. The mechanical characteristics of the workpiece machined subsurface layers were the microhardness of the subsurface layers and the total work of indenter penetration, determined by instrumental nanoindentation, and the maximum depth of indenter penetration, determined by sclerometry. Titanium alloy Ti10V2Fe3Al (Ti-1023) was used as the machining material. Based on the evaluation of the coincidence of the cutting process energy characteristics with the specified mechanical characteristics of the machined subsurface layers, the milling mode effect of the studied titanium alloy, in particular the cutter feed and cutting speed, on the generated mechanical characteristics was established.Item Open Access Technology selection for inline topography measurement with rover-borne laser spectrometers(2024) Ryan, Conor; Haist, Tobias; Laskin, Gennadii; Schröder, Susanne; Reichelt, StephanThis work studies enhancing the capabilities of compact laser spectroscopes integrated into space-exploration rovers by adding 3D topography measurement techniques. Laser spectroscopy enables the in situ analysis of sample composition, aiding in the understanding of the geological history of extraterrestrial bodies. To complement spectroscopic data, the inclusion of 3D imaging is proposed to provide unprecedented contextual information. The morphological information aids material characterization and hence the constraining of rock and mineral histories. Assigning height information to lateral pixels creates topographies, which offer a more complete spatial dataset than contextual 2D imaging. To aid the integration of 3D measurement into future proposals for rover-based laser spectrometers, the relevant scientific, rover, and sample constraints are outlined. The candidate 3D technologies are discussed, and estimates of performance, weight, and power consumptions guide the down-selection process in three application examples. Technology choice is discussed from different perspectives. Inline microscopic fringe-projection profilometry, incoherent digital holography, and multiwavelength digital holography are found to be promising candidates for further development.Item Open Access An exploratory analysis of the current status and potential of service-oriented and data-driven business models within the sheet metal working sector : insights from interview-based research in small and medium-sized enterprises(2024) Wirth, Jonas; Schneider, Mirko; Hanselmann, Leon; Fink, Kira; Nebauer, Stephan; Bauernhansl, ThomasResponding to changing value creation processes in the sheet metal working sector, where the complexity and interchangeability of products challenge traditional differentiation strategies, this exploratory analysis examines the integration of service-oriented and data-driven business models as new paths to ensure competitiveness, especially for small and medium-sized enterprises (SMEs). This study aims to capture the current state and challenges associated with the implementation of these business models in this sector. This research was conducted through semi-structured interviews with SMEs in the industry. The findings indicate that service-oriented and data-driven business models are not yet widely adopted and that manufacturing companies require support in their implementation. Fields of action were identified for the industry. These are “Creating awareness and understanding”, “Recognizing added value”, “Increasing company maturity”, and “Understanding the change process”. Cooperation between science and industry is essential in tackling these fields of action to ensure the successful integration of such business models in manufacturing companies. This paper identifies challenges in the fields of action that companies must address through a structured approach, promoting awareness, recognizing value, improving organizational maturity, and understanding the change process to successfully implement service-oriented and data-driven business models.Item Open Access Enzyme-assisted circular additive manufacturing as an enabling technology for a circular bioeconomy : a conceptual review(2024) Protte-Freitag, Kristin; Gotzig, Sophia; Rothe, Hannah; Schwarz, Oliver; Silber, Nadine; Miehe, RobertAdditive manufacturing (AM) is a decisive element in the sustainable transformation of technologies. And yet its inherent potential has not been fully utilized. In particular, the use of biological materials represents a comparatively new dimension that is still in the early stages of deployment. In order to be considered sustainable and contribute to the circular economy, various challenges need to be overcome. Here, the literature focusing on sustainable, circular approaches is reviewed. It appears that existing processes are not yet capable of being used as circular economy technologies as they are neither able to process residual and waste materials, nor are the produced products easily biodegradable. Enzymatic approaches, however, appear promising. Based on this, a novel concept called enzyme-assisted circular additive manufacturing was developed. Various process combinations using enzymes along the process chain, starting with the preparation of side streams, through the functionalization of biopolymers to the actual printing process and post-processing, are outlined. Future aspects are discussed, stressing the necessity for AM processes to minimize or avoid the use of chemicals such as solvents or binding agents, the need to save energy through lower process temperatures and thereby reduce CO2 consumption, and the necessity for complete biodegradability of the materials used.Item Open Access A 10 V transfer standard based on low-noise solid-state Zener voltage reference ADR1000(2024) Bülau, André; Walter, Daniela; Zimmermann, AndréVoltage standards are widely used to transfer volts from Josephson voltage standards (JVSs) at national metrology institutes (NMIs) into calibration labs to maintain the volts and to transfer them to test equipment at production lines. Therefore, commercial voltage standards based on Zener diodes are used. Analog Devices Inc. (San Jose, CA, USA), namely, Eric Modica, introduced the ADR1000KHZ, a successor to the legendary LTZ1000, at the Metrology Meeting 2021. The first production samples were already available prior to this event. In this article, this new temperature-stabilized Zener diode is compared to several others as per datasheet specifications. Motivated by the superior parameters, a 10 V transfer standard prototype for laboratory use with commercial off-the-shelf components such as resistor networks and chopper amplifiers was built. How much effort it takes to reach the given parameters was investigated. This paper describes how the reference was set up to operate it at its zero-temperature coefficient (z.t.c.) temperature and to lower the requirements for the oven stability. Furthermore, it is shown how the overall temperature coefficient (t.c.) of the circuit was reduced. For the buffered Zener voltage, a t.c. of almost zero, and with amplification to 10 V, a t.c. of <0.01 µV/V/K was achieved in a temperature span of 15 to 31 °C. For the buffered Zener voltage, a noise of ~584 nVp-p and for the 10 V output, ~805 nVp-p were obtained. Finally, 850 days of drift data were taken by comparing the transfer standard prototype to two Fluke 7000 voltage standards according to the method described in NBS Technical Note 430. The drift specification was, however, not met.Item Open Access Hydrogen micro-systems : households’ preferences and economic futility(2024) Klingler, Anna-Lena; Dörr, JulianThis study examines the potential market for residential hydrogen systems in light of the trends towards digitalisation and environmental awareness. Based on a survey of 350 participants, the results indicate that although energy experts are sceptical about the benefits of residential hydrogen systems due to their high costs, households are highly interested in this technology. The sample shows a willingness to invest in hydrogen applications, with some households willing to pay an average of 24% more. An economic assessment compared the cost of a residential hydrogen system with conventional domestic energy systems, revealing significant additional costs for potential buyers interested in hydrogen applications.Item Open Access Cu-doped calcium phosphate supraparticles for bone tissue regeneration(2024) Höppel, Anika; Bahr, Olivia; Ebert, Regina; Wittmer, Annette; Seidenstuecker, Michael; Carolina Lanzino, M.; Gbureck, Uwe; Dembski, SofiaCalcium phosphate (CaP) minerals have shown great promise as bone replacement materials due to their similarity to the mineral phase of natural bone. In addition to biocompatibility and osseointegration, the prevention of infection is crucial, especially due to the high concern of antibiotic resistance. In this context, a controlled drug release as well as biodegradation are important features which depend on the porosity of CaP. An increase in porosity can be achieved by using nanoparticles (NPs), which can be processed to supraparticles, combining the properties of nano- and micromaterials. In this study, Cu-doped CaP supraparticles were prepared to improve the bone substitute properties while providing antibacterial effects. In this context, a modified sol-gel process was used for the synthesis of CaP NPs, where a Ca/P molar ratio of 1.10 resulted in the formation of crystalline β-tricalcium phosphate (β-TCP) after calcination at 1000 °C. In the next step, CaP NPs with Cu 2+ (0.5-15.0 wt%) were processed into supraparticles by a spray drying method. Cu release experiments of the different Cu-doped CaP supraparticles demonstrated a long-term sustained release over 14 days. The antibacterial properties of the supraparticles were determined against Gram-positive ( Bacillus subtilis and Staphylococcus aureus ) and Gram-negative ( Escherichia coli ) bacteria, where complete antibacterial inhibition was achieved using a Cu concentration of 5.0 wt%. In addition, cell viability assays of the different CaP supraparticles with human telomerase-immortalized mesenchymal stromal cells (hMSC-TERT) exhibited high biocompatibility with particle concentrations of 0.01 mg mL -1 over 72 hours.Item Open Access A data-driven approach for cutting force prediction in FEM machining simulations using gradient boosted machines(2024) Reeber, Tim; Wolf, Jan; Möhring, Hans-ChristianCutting simulations via the Finite Element Method (FEM) have recently gained more significance due to ever increasing computational performance and thus better resulting accuracy. However, these simulations are still time consuming and therefore cannot be deployed for an in situ evaluation of the machining processes in an industrial environment. This is due to the high non-linear nature of FEM simulations of machining processes, which require considerable computational resources. On the other hand, machine learning methods are known to capture complex non-linear behaviors. One of the most widely applied material models in cutting simulations is the Johnson-Cook material model, which has a great influence on the output of the cutting simulations and contributes to the non-linear behavior of the models, but its influence on cutting forces is sometimes difficult to assess beforehand. Therefore, this research aims to capture the highly non-linear behavior of the material model by using a dataset of multiple short-duration cutting simulations from Abaqus to learn the relationship of the Johnson-Cook material model parameters and the resulting cutting forces for a constant set of cutting conditions. The goal is to shorten the time to simulate cutting forces by encapsulating complex cutting conditions in dependence of material parameters in a single model. A total of five different models are trained and the performance is evaluated. The results show that Gradient Boosted Machines capture the influence of varying material model parameters the best and enable good predictions of cutting forces as well as deliver insights into the relevance of the material parameters for the cutting and thrust forces in orthogonal cutting.Item Open Access The “Fluid Jacobian” : modeling force-motion relationships in fluid-driven soft robots(2024) Remy, C. David; Brei, Zachary; Bruder, Daniel; Remy, Jan; Buffinton, Keith; Gillespie, R. BrentIn this paper, we introduce the concept of the Fluid Jacobian, which provides a description of the power transmission that operates between the fluid and mechanical domains in soft robotic systems. It can be understood as a generalization of the traditional kinematic Jacobian that relates the joint space torques and velocities to the task space forces and velocities of a robot. In a similar way, the Fluid Jacobian relates fluid pressure to task space forces and fluid flow to task space velocities. In addition, the Fluid Jacobian can also be regarded as a generalization of the piston cross-sectional area in a fluid-driven cylinder that extends to complex geometries and multiple dimensions. In the following, we present a theoretical derivation of this framework, focus on important special cases, and illustrate the meaning and practical applicability of the Fluid Jacobian in four brief examples.