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Buch
Abschlussergebnisbericht - KMU-Wissenstransferlabor „Digitale Fabrik“
(2023-04)
Der digitale Wandel stellt aufgrund der hohen Gestaltungskomplexität insbesondere kleine und mittlere Unternehmen (KMU) immer noch vor große Herausforderungen. Reifegradmodelle und Roadmaps bieten Möglichkeiten, diese Komplexität beherrschbar zu machen. Vor diesem Hintergrund hat das Fachgebiet Produktionsorganisation und Fabrikplanung an der Universität Kassel im Rahmen des Forschungsprojektes Wissenstransferlabor „Digitale Fabrik“ (Wislab) ein KMU-spezifisches Reifegradmodell, einen zugehörigen Erhebungsleitfaden ...
Dissertation
Modellierung von offenen Absorptionsanlagen zur Raum- und Prozessluftentfeuchtung
(2023)
Luftentfeuchtung erfolgt in herkömmlichen Trocknungs- und Klimatisierungsanlagen durch eine Kühlung der feuchten Luft unter ihren Taupunkt (Kondensationsentfeuchter) und einer anschließenden Erwärmung bis zu der gewünschten Temperatur. Das Prinzip dieser Betriebsweise birgt einen unnötigen Stromverbrauch. In der vorliegenden Dissertation wird daher ein alternatives Luftentfeuchtungsverfahren beschrieben, bei dem die Luftentfeuchtung durch einen offenen Absorptionsprozess realisiert wird. In dem offenen Absorptionsprozess ...
Dissertation
Die Gestaltung gesunder und effektiver digital vermittelter Kommunikation im Kontext von Remote Leadership – eine Betrachtung unter Berücksichtigung des Aspektes der psychologisch sicheren Kommunikation
(2023)
Einhergehend mit einer fortschreitenden Globalisierung und Digitalisierung nimmt auch die Verbreitung von Remote Leadership, auf Distanz vermittelter Führungs- und Kommunikationsprozesse, seit mehreren Jahren stetig zu; im Zuge der Covid-19-Pandemie hat sich diese Entwicklung nochmals beschleunigt. Unternehmen, die angesichts eines internationalen Wettbewerbs mit einem wachsenden Innovations- und Optimierungsdruck konfrontiert sind, müssen in der modernen Arbeitswelt, wollen sie wettbewerbsfähig und erfolgreich ...
Aufsatz
Beam powder bed fusion for direct microstructure design – In-depth analysis of prospects and limitations of the multi spot scanning strategy
(2023)
The electron beam powder bed fusion process generally results in a strong 〈001〉 texture alongside the build direction for Inconel 718. This is a result of prevailing high thermal gradients between the melted surface and the solid material. However, based on specific beam movement patterns, the solidification behaviour can be altered towards an equiaxed, isotropic microstructure. The present study focuses on the “multi spot scanning” strategy directly provided by the machine manufacturer. The operation mode of the ...
Aufsatz
On the Monotonic and Cyclic Behavior of an Al-Mg-Zn-Cu-Si Compositionally Complex Alloy
(2023-08-03)
In present work, the monotonic and cyclic properties of a novel Al-Mg-Zn-Cu-Si compositionally complex alloy (CCA) are investigated. Microstructural studies reveal that a eutectic phase and fishbone-type structures are embedded in the Al-matrix. The mechanical properties of this CCA obtained under compressive loading are found to be promising. However, low ultimate strength and brittle behavior are seen under tension. The fatigue performance of the alloy in the low-cycle fatigue (LCF) regime is poor. Microstructural ...
Aufsatz
Hot Sheet Metal Forming Strategies for High-Strength Aluminum Alloys: A Review—Fundamentals and Applications
(2023-05-17)
In the past decade, aluminum alloys have become important structural materials in the automotive industry, thanks to their low density, high strength, high fracture toughness, and good fatigue performance. However, an important limitation of aluminum alloys is their poor formability at room temperature; as a result, numerous studies have been conducted with the aim of developing forming techniques to overcome this and facilitate the forming of more complex-shaped components. Following an overview on the metallurgical ...
Aufsatz
Experimental Analysis of the Stability of Retained Austenite in a Low-Alloy 42CrSi Steel after Different Quenching and Partitioning Heat Treatments
(2023-06-21)
Quenching and partitioning (Q&P) steels are characterized by an excellent combination of strength and ductility, opening up great potentials for advanced lightweight components. The Q&P treatment results in microstructures with a martensitic matrix being responsible for increased strength whereas interstitially enriched metastable retained austenite (RA) contributes to excellent ductility. Herein, a comprehensive experimental characterization of microstructure evolution and austenite stability is carried out on a ...
Aufsatz
Electron Beam Welding of Hot-Rolled Fe–Mn–Al–Ni Shape Memory Alloy Sheets
(2023-04-25)
The present study focuses on the weldability of hot-rolled Fe–Mn–Al–Ni shape memory alloy sheets by vacuum electron beam welding. Tailored process-specific welding parameters, such as preheating with electron beam or beam oscillation during welding, allowed defect-free joining with very thin weld seams and heat-affected zones. By applying a post-weld cyclic heat treatment, abnormal grain growth can be promoted across the weld seams. However, regardless of the selected welding parameters, some specimens are characterized ...
Aufsatz
Low-Cycle-Fatigue Performance of Stress-Aged EN AW-7075 Alloy
(2023-05-05)
The effect of a novel heat treatment, that is, aging under superimposed external stress, on the fatigue performance and microstructural evolution of a high-strength aluminum alloy (EN AW-7075) is presented. Stress aging, a combination of heat treatment and superimposed external stress, can enhance the mechanical properties of EN AW-7075 under monotonic loading due to the acceleration of precipitation kinetics. Scanning electron microscopy (SEM) and scanning transmission electron microscopy (STEM) reveal that a longer ...
Aufsatz
On the Reliability of Automated Analysis of Fracture Surfaces Using a Novel Computer Vision-Based Tool
(2023-08-05)
Fracture surface analysis is of utmost importance with respect to structural integrity of metallic materials. This especially holds true for additively manufactured materials. Despite an increasing trend of automatization of testing methods, the analysis and classification of fatigue fracture surface images is commonly done manually by experts. Although this leads to correct results in most cases, it has several disadvantages, e.g., the need of a huge knowledge base to interpret images correctly. In present work, an ...