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Das kontinuierliche Streben, Strukturbauteile immer ressourcenschonender und effizienter zu gestalten, führt zu einer Reduktion der Bauteilmasse, aber auch der Dämpfung. Allerdings stellen Dämpfungsmechanismen einen entscheidenden Faktor zur Beeinflussung des Schwingungsverhaltens dynamischer Systeme dar. So können z. B. Fahrzeugschwingungen den Fahrkomfort mindern oder im schlimmsten Fall zum Bauteilversagen führen. Einen effektiven, kostengünstigen und einfach zu integrierenden Ansatz zur Schwingungsreduktion, stellt der Effekt der Partikeldämpfung dar. Insbesondere in pulverbettbasierten additiven Fertigungsverfahren wie dem PBF-LB/M, kann während des Bauprozesses unverschmolzenes Pulver in dafür vorgesehenen Bauteilkavitäten belassen und so ein hochintegrierter Partikeldämpfer gefertigt werden. Durch eine Integration der pulvergefüllten Kavitäten im Bereich der neutralen Faser kann eine hohe Dämpfung bei geringfügiger Beeinflussung der Bauteilmasse und -steifigkeit realisiert werden. Neben den zahlreichen Vorteilen ist der Einsatz laserstrahlgeschmolzener Partikeldämpfer jedoch aktuell noch stark limitiert. Die Ursachen sind vor allem die zahlreichen Auslegungsparameter, die hochgradig nichtlineare Wechselwirkungen aufweisen. Infolge dessen liegen noch keine ausreichenden Auslegungswerkzeuge wie Kennfelder, mechanische Ersatzmodelle oder Gestaltungsrichtlinien vor. Der erste Aspekt dieser Arbeit widmet sich der experimentellen Charakterisierung laserstrahlgeschmolzener Partikeldämpfer aus Aluminium AlSi10Mg und Werkzeugstahl 1.2709. Neben dem Material, werden die relevanten Einflussfaktoren Anregungskraft, Frequenz und Hohlraumvolumen analysiert. Dazu wird eine Impulshammeranregung von Biegebalken durchgeführt und die Dämpfung über das Circle-Fit Verfahren ausgewertet. Dabei konnte für ausgewählte partikelgedämpfte Balken die Dämpfung um bis zu einem Faktor von 20 gegenüber einem vollversinterten Referenzbalken gesteigert werden. Anschließend wird ein mechanisch

Additive manufacturing using Powder Bed Fusion by Laser Beam (PBF-LB) enables products with high design freedom. In addition, the ability to process more than one material in all three spatial directions makes it possible to produce highly functional components in one single process. This article investigates whether multi-material manufacturing using PBF-LB is suitable for producing coils for electric motors, which are designed with integrated cooling channels to increase the power density. For this purpose, the copper alloy CuCr1Zr for the coils and the stainless steel 1.4404 (316L) for the core are processed simultaneously. The component designs were verified using 2D and 3D finite element analysis and then manufactured in a multi-material PBF-LB process. While good electrical conductivity of the copper alloy was achieved by heat treatment, it was found that thermal distortion caused deviations from the nominal geometry. The measurement of the electrical properties showed that this distortion leads to short-circuit currents within the coils and the teeth. On this basis, ideas for solutions were developed, with the help of which the functionality of the coils can be ensured or the power density can also be increased. In addition to adapting the design of the component, this includes processing additional or other materials, such as soft magnetic composites.

The deep-drawability of a sheet metal blank is strongly influenced by the tribological conditions prevailing in a deep-drawing process. Therefore, new methods to influence the tribology represent an important research topic. In this work, the application of a process-integrated lubrication in a deep-drawing process is investigated. Most promising geometries of the lubrication channels and outlet openings are first identified by means of numerical simulation at the example of a demonstrator process. Cylindrical test specimens with the specified channel geometries are additively manufactured and installed in a strip drawing test stand. Additive manufacturing enables the possibility of manufacturing complex channel geometries which cannot be manufactured by conventional methods. A hydraulic metering device for conveying lubricant is connected to the cylindrical test specimens. Thus, hydraulically lubricated strip drawing tests are performed. The tests are evaluated according to the force curves and the fluid mechanical buildup of pressure cushion. The performance of process-integrated lubrication is thus analyzed and evaluated. By means of a coupled forming and SPH simulation, the lubrication channels could be optimally designed. From the practical tests, it could be achieved that the drawing force decreases up to 27% with pressure cushion build up. In this research, a hydraulic lubrication in the area of highest contact normal stresses is the most optimal process parameter regarding friction reduction.

Additively manufactured particle dampers can significantly improve component damping. However, if designed incorrectly, the damping can be worsened. For the design of additively manufactured particle dampers, there are not yet sufficient design rules and models to describe the effect due to numerous design parameters. The research question answered in this paper describes how the effect of particle damping can be characterised as a function of excitation force and excitation frequency for different cavity sizes. To characterise the effect of particle damping, a 33 full factorial test plan is constructed, and the damping is determined experimentally. It is shown that the damping can be reliably evaluated with the circle‐fit method. The effect of particle damping is investigated for beams made of AlSi10Mg, 1.2709 and Ti6Al4V. As a result, a positive effect of the particle damping in a frequency range from 500 to 30,000 Hz and partly up to the 9th bending mode can be proven. It is shown that, for the first bending mode, there is an optimum at approx. 2000 Hz. For the optimum, the increase of the damping for the tool steel 1.2709 to 28 and for the aluminium alloy AlSi10Mg to 18 can be proven. © 2022 by the authors. Licensee MDPI, Basel, Switzerland.

Damping mechanisms are a crucial factor for influencing the vibration behavior of dynamic systems. In many applications vibrations are undesirable and need to be reduced by appropriate measures. For instance, vibrations in vehicles can reduce driving comfort or in civil engineering resonance damage can occur in constructions. An interesting and cost-effective way of increasing damping is particle damping. In modern processes of additive manufacturing, like laser powder bed fusion (LPBF), unmelted powder can be left inside a structure on purpose after making and thus producing integrated particle dampers already. Additively manufactured particle damping has not yet reached the industrial level because there are no detailed specifications for the design process. This includes the modeling of (non-linear) dynamic properties, based on numerous design parameters. The state of the art reveals that the effect of particle damping has been convincingly demonstrated, but transferability of the obtained information is still limited. In this paper the effect of particle damping is investigated experimentally with LPBF manufactured beam structures made of AlSi10Mg. Particle damping is evaluated in terms of performance curves for different beam parameter sets. The aim is to help the designer, who needs to keep amplitudes in certain range to estimate the damping of the potential particle damper via the given performance curves. Damping is determined via experimental modal analysis by impulse excitation. The response is evaluated in the frequency domain using the Circle-Fit method with a focus on the beams first bending mode of vibration. Beyond that, a significantly increased damping could be verified up to the seventh bending mode covering a frequency range between 600 Hz and 18k Hz. Damping through particle-filled cavities shows up to 20 times higher damping compared to the same component with fused powder.

In the event of damage to additively manufactured components whose shape cannot be produced by machining, an additive repair can potentially be not only ecologically but also ecologically more favorable than the production of a new component. In addition, a number of hurdles that otherwise often impede the use of additive repair, e.g. the availability of the material of the damaged component for the additive process, are eliminated. As far as the authors are aware, this publication is the first to present a process for the additive refurbishment of additively manufactured components using the example of a wheel carrier. In this context, the possibility of increasing the fatigue strength of a structural component in refurbishment is discussed for the first time. To increase the fatigue strength of the wheel carrier, the chosen approach is to integrate the effect of particle damping into the component. Particularly in the case of components subjected to bending stresses, the effect of particle damping can be integrated into the component's interior without having to accept a significant loss of strength.