Fraunhofer-Institut für Produktionsanlagen und Konstruktionstechnik IPK

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Simulating flow behaviour of wet particles within the immersed tumbling process

2021 , Uhlmann, Eckart , Polte, Julian , Kuche, Yves , Landua, Fabian

For many production chains, it is mandatory to involve special finishing of the manufactured parts for the chipping of the edges as well as the polishing of surfaces. One commonly used method is the immersed tumbling process, where any workpiece is dragged through a particle filled container. In many cases, the immersed tumbling process operates in environments with added liquids, leading to changes in particle-tool interaction and general flow behaviour of the used particles. Whilst the discrete element method for simulating particles is mainly limited to dry particles, the used software ROCKY DEM from ESSS, Florianópolis, Brasil, comes with a built-in liquid-bridge model to simulate water-covered particles and granulate and furthermore an extension for system couplings with Ansys Fluent of the company ANSYS, INC., Canonsburg, Pennsylvania. The latter can be used to create from both software one three-phase-model with higher amounts of actually simulated water. In thi s study, small amounts of water were added to differently shaped particles using the build-in liquid-bridge model, to analyse and compare the particles flow characteristics in both, wet and dry environments. To gather significant information leading towards precise comparisons, the particles trajectories, velocities and resulting forces against the workpieces can be specifically observed and analysed, whilst this kind of process knowledge could previously never been taken into account without simulation.

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Concept for an actuated variable tool electrode for use in sinking EDM

2021 , Uhlmann, Eckart , Streckenbach, Jan , Thißen, Kai , Schulte Westhoff, Bela , Masoud, Abd Elkarim , Maas, Jürgen

Typically, a large number of individual tool electrodes has to be used in sinking electrical discharge machining (sinking EDM) to successfully machine a single workpiece. Due to non-uniform wear and insufficient flushing of the working gap electrode geometries have a significant effect on the process efficiency. This paper discusses the use of an actuated variable tool electrode for sinking EDM to reduce the number of required tool electrodes and to increase the overall process efficiency. A miniaturised linear actuator was developed to individually move electrode segments to form the target shape for the tool electrode. The coordinated actuation of bundled electrode segments introduces new methods for the active flushing within the working gap, which cannot be implemented in conventional sinking EDM. Intelligent sinking strategies can further improve process efficiency by creating and sinking sub-geometries into the workpiece offering improved flushing conditions compa red to the original geometry.

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Photocatalytic effect of TiO2-coated surfaces on the pathogenic microorganisms E.coli and S.aureus

2021 , Uhlmann, Eckart , Hein, Christoph , Brehmer, Annika

The use of titanium dioxide as a strong photocatalytic substance can have a large effect in combating the spread of pathogens through heavily contaminated surfaces. For this purpose, various materials, such as metal, glass, and polymer were coated with rutile- and anatase-rich titanium dioxide by sol-gel method. The contact angle and photocatalytic activity of the coated surface were measured under UV irradiation. The anatase-rich titanium dioxide showed higher photocatalytic activity, which further increased with the coating thickness. The process temperature had an effect on the photocatalytic activity due to the temperature-dependent conversion of anatase to rutile crystal conformation. The coated surfaces had strongly reduced contact angles compared to the uncoated material. In particular, the anatase-rich surfaces resulted in superhydrophilic properties. Photocatalytically induced antibacterial activity against pathogenic microorganisms in liquid environments was d emonstrated, especially for gram-negative Escherichia coli bacteria.

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Validation of Immersive Design Parameters in Driving Simulation Environments

2021 , Lyga, Yvonne , Lau, Merle , Brandenburg, Elisabeth , Stark, Rainer

Driving simulators are used for the prospective validation of technical systems in the automotive sector. The design of simulation environments can affect drivers and should be considered in investigations of driver-vehicle interactions. The aim of this research is to minimize the gap between driving simulators and real car studies by integrating immersive parameters into simulated driving environments. Stereoscopy, surround sound and motion feedback were analyzed with regard to driver behavior and experience and were then compared to data of a real drive from a previous investigation. The authors conducted a study with N = 48 participants performing a dual-task scenario in a driving simulator. Results reveal significant effects of immersive design parameters on gaze behavior and mental workload. Findings provide guidance for an efficient and cost-effective development of driving simulation environments.

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Time-Sensitive Networking over Metropolitan Area Networks for Remote Industrial Control

2021 , Tschöke, Simon , Lynker, Frederic , Buhr, Hauke , Schreiner, Florian , Willner, Alexander , Vick, Axel , Chemnitz, Moritz

The benefits of the currently evolving IEEE Time-Sensitive Networking (TSN) standard have already been globally recognized. Whereas the application of TSN in a LAN is currently widely and globally tested, TSN in a Metropolitan Area Network (MAN) has not been a major focus until now. The possible benefits of utilizing co-located Edge Clouds in order to support multiple urban production sites with industrial realtime applications open a wide range of new business models. Therefore, we have analyzed the feasibility of transparently using PROFINET over TSN via a Dense Wavelength Division Multiplex (DWDM) link, where a machine park is controlled remotely by an Edge-based virtual Programmable Logic Controller (vPLC). As a result, we are able to setup a TSN connection over a MAN with a one-way delay of about 156.5 J.ms and a jitter of about 12 ns. This work can be extended to allow for dynamically provisioned TSN flows and multi-path Frame Replication and Elimination (FRER) for distributed hard real-time machine control and adoption to Ultra-Reliable Low-Latency Communication (URLLC) 5G campus networks.

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Interaction between capabilities of Model Based Systems Engineering on sensor models

2021 , Manoury, Marvin Michael , Schmidt, Simon , Stark, Rainer

In modern product development, models are often used for different purposes, e.g., system synthesis, trade-off analysis of system parameters or visualization and creation of design concepts. For some models, this purpose as well as the model itself might change over time. New interactions with the target system can occur and new details are added over time. Both have to be integrated immediately into the development procedure. When models are not maintained up to date and not used by different stakeholders, the benefits of the model-based approach are lessened due to the effort for generation and maintenance. The five development capabilities of MBSE, comprising Systems Environment Analytics (SEA), Systems Definition and Derivation (SDD), Systems Interaction Modeling (SIM), Systems Lifecycle Engineering (SLE) and the MBSE Capability and Maturation Matrix (CMM) address this topic on a capability level.In this article, the authors point out the interaction between these d evelopment capabilities on the example of a Pedestrian Emergency Braking System (PEBS) development in automotive industry, with a focus on sensor models. It will be shown exemplary how one development capability might influence another and how this interaction supports the development of complex systems.

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A contribution to the interpretation of organizational resilience (Or) based on the analysis of key drivers and conceptual elements

2021 , Hecklau, Fabian , Kidschun, Florian , Kohl, Holger , Hizal, Gamze Gül

Organizations are increasingly confronted with unexpected events, which can occur within or outside the organization and relate to various dimensions or aspects. The significance and extent of its impact on the organization can be quite surprising (Duchek 2020). Despite the fact that academic interest in this subject area has grown steadily in recent years, its conceptualization is not yet fully developed. There is no consensus on the meaning of resilience and the elements it contains. This paper contributes to the understanding and need for organizational resilience (OR) and also reveals gaps in its conceptualization. Resilience is understood as the ability of an organization to repel, prepare for, consider, absorb, recover from and adapt ever more successfully to actual or potential adverse events. Those events are either catastrophes or processes of change with catastrophic outcome which can have human, technical or natural causes.(Thoma 2014) In order to survive in an uncertain environment and promote future success, organizations must be able to deal with all these manifestations of the unexpected and catapult themselves out of the crisis. They have to develop a capacity for resilience that enables them to react appropriately to unexpected events and to make capital from events that could potentially threaten the survival of an organization (Lengnick-Hall et al. 2011; Duchek 2020; Denyer 2017; Aguilar 1967). In literature and practice, there are various approaches to OR, which consist of phase models that also allow an assessment of an organization as resilience using a maturity model. From the examined methods in this paper it follows that the resilience capability is questioned only after occurrence of an adverse event and no "preparation phase" according to the Fraunhofer resilience cycle exists. This ex post approach endangers not only the competitive position, but also the existence of an organization.

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How Pedestrians Perceive Autonomous Buses: Evaluating Visual Signals

2021 , Brandenburg, Elisabeth , Kozachek, Diana , Konkol, Kathrin , Woelfel, Christiane , Geiger, Andreas , Stark, Rainer

With the deployment of autonomous buses, sophisticated technological systems are entering our daily lives and their signals are becoming a crucial factor in human-machine interaction. The successful implementation of visual signals requires a well-researched human-centred design as a key component for the new transportation system. The autonomous vehicle we investigated in this study uses a variety of these: Icons, LED panels and text. We conducted a user study with 45 participants in a virtual reality environment in which four recurring communication scenarios between an autonomous driving bus and its potential passengers had to be correctly interpreted. For our four scenarios, efficiency and comprehension of each visual signal combination was measured to evaluate performance on different types of visual information. The results show that new visualization concepts such as LED panels lead to highly variable efficiency and comprehension, while text or icons were well ac cepted. In summary, the authors of this paper present the most efficient combinations of visual signals for four reality scenarios.

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Towards a Framework for Impact Assessment of Research & Technology Organisations

2021 , Kidschun, Florian , Hecklau, Fabian

Due to their ability to bridge the gap between knowledge created by basic research and market requirements, Research and Technology Organisations (RTOs) play a major role in countriesâ innovation systems. Their R&D results should lead to innovations, which in turn generate the economic output of public investment in research and development. Moreover, they should support the foundation of new companies and industrial innovations. RTOs can thus be seen as intermediaries between R&D and the industry, while they themselves constitute to a certain extent entrepreneurs and actors in applied R&D that focus on industrial and commercial application right from the start of their activities. Therewith, RTOs pursue to increase the competitiveness of the entire economy. With a growing demand for evaluating their actual contribution in national innovation systems, simply stating the goal of positive impact to stakeholders like governments, the public, investors etc. is not enough; its accomplishment needs to be proven by robust evidence. In this regard, the value of an impact assessment is determined by the strength of the evidence produced and the credibility of the evaluation. RTOâs research activities and their impacts are diverse in nature and occur across many sectors of the economy. To gain transparent insights into relevant and comprehensive performance metrics showing the impact of RTOs from a micro- and macroeconomic perspective, impacts are only appropriate for evaluation if a causal relationship can be drawn back to their origin. While some impacts are primarily economic and suitable for quantitative analysis, others have to be evaluated qualitatively. Regardless of its type, each impact needs to be assessed within a common framework to enable a comprehensive understanding of RTO's impact. Within this contribution, an impact assessment framework is established with the aim to enable the identification of causal relationships between impacts and their origin.

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Business model development in European aerospace start-ups: The case of the spaceup project

2021 , Steinhöfel, Erik , Singer, Katrin

In their quest for market establishment and organizational maturity, business model development (BMD) plays a crucial role for start-ups. After foundation, primary focus is no longer on generating promising business ideas, but on commercializing a start-upâs inherent potential. This particularly applies to innovative, technology-based start-ups. Here, superior functions in relation to existing solutions resulting from advancements in technologies and the value associated with such functional superiority are center of entrepreneurial activity and BMD. This study presents the BMD methodology applied for supporting 60 technology-based, aerospace-related start-ups on their path to becoming leading companies in their field and the results of its application in the frame of the SpaceUp project. The methodology was carried out in a two-stage process. First, a questionnaire was provided to the start-ups to capture and assess their business model (BM). In a second step, based on the information provided, a detailed evaluation of the start-upsâ BM was carried out and starting points for further development were generated. In order to assess the relevance and usefulness of the results generated by applying the methodology, a quantitative survey was conducted among the start-ups. The survey showed that the generated results were perceived as beneficial by the start-ups and that the application of the methodology therefore proved successful in the project.

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