1,425 research outputs found
Feeling machine for process monitoring of components with stock allowance
To realize the increasing automation and flexibilization of production, it is necessary to monitor component-specific characteristics under fluctuating production conditions. Signals with a high correlation to the process quality have to be evaluated. In machining, the process force is an important measurand, which is sensitive to changes in the process. Feeling machines with force-sensitive machine tool components are therefore a promising signal source to monitor the machining. However, the force is also sensitive to non-critical process fluctuations such as stock allowance. Consequently, it is necessary to perform signal pre-processing and generate features that increase the robustness of the monitoring. In this paper, the material-specific cutting force was investigated for the first time concerning its suitability for process monitoring of parts with a stock allowance. The sensitivity of confidence limits was evaluated based on the normed bandgap. For the investigation, face turning processes of 20MnCr5 were carried out. The results show that the use of material-specific cutting force improves the sensitivity of the confidence limits to process errors. In this context, the feeling machine can be used to substitute the dynamometer for process monitoring. © 2021 by the authors. Licensee MDPI, Basel, Switzerland
Feeling machine for process monitoring of turning hybrid solid components
The realization of the increasing automation of production systems requires the guarantee of process security as well as the resulting workpiece quality. For this purpose, monitoring systems are used, which monitor the machining based on machine control signals and external sensors. These systems are challenged by innovative design concepts such as hybrid components made of different materials, which lead to new disturbance variables in the process. Therefore, it is important to obtain as much process information as possible in order to achieve a robust and sensitive evaluation of the machining. Feeling machines with force sensing capabilities represent a promising approach to assist the monitoring. This paper provides, for the first time, an overview of the suitability of the feeling machine for process monitoring during turning operations. The process faults tool breakage, tool wear, and the variation of the material transition position of hybrid shafts that were researched and compared with a force dynamometer. For the investigation, longitudinal turning processes with shafts made of EN AW-6082 and 20MnCr5 were carried out. The results show the feeling machine is sensitive to all kinds of examined errors and can compete with a force dynamometer, especially for roughing operations. © 2020 by the authors. Licensee MDPI, Basel, Switzerland
Transfer as a reciprocal process: How to foster receptivity to results of transdisciplinary research
Transdisciplinary research (TDR) seeks to address real-world problems and aims to be socially transformative. This normative objective extends beyond particular TDR projects, as real-world problems are embedded in concrete contexts but, at the same time, are also related to wider societal challenges that are not restricted to one context. Therefore, TDR generally entails transfer of knowledge and results to other contexts. However, the TDR discourse has mainly treated transfer efforts from the perspective of scientific generalization, translation and packaging of knowledge. Within this understanding of transfer, little attention has been paid to interplay between contexts and the role of new contexts themselves.
This article is based on qualitative explorative research on four TDR projects. Its results were iteratively derived through project analysis, reflection on insights from the literature and discussions with TDR experts. We propose that transfer is a complex reciprocal process in which different types of knowledge are provided and transferred to other contexts, where knowledge is adapted, enriched and modified. In addition to project researchers, actors in other (pick-up) contexts also play an important role for successful transfer and appropriation of TDR results. Generating transfer potential within the duration of a project depends on being aware of potential pick-up contexts. To address the interdependent aspects of transfer (results, mediation, and appropriation in other contexts), we present a comprehensive model outlining TDR transfer processes. To support projects seeking to raise their transfer potential in a more conscious manner, we also formulate three overarching recommendations: 1) process results for transfer adequately, 2) identify and support intermediaries and, 3) increase awareness of and address other contexts. Considering these recommendations while also being aware of their interdependence may increase potential for transfer of knowledge and results to other contexts. Our conceptual understanding acknowledges the complexity and non-linearity of endeavors to take advantage of case-specifically gained knowledge and results in other contexts or at other scales
Societal effects of transdisciplinary sustainability research—How can they be strengthened during the research process?
Transdisciplinary sustainability research aims to mitigate or to solve complex societal problems and advance the production of scientific knowledge. Reflexive approaches to transdisciplinary research processes are outlined to systematically strengthen the potential for societal effectiveness. So far, it is rare to find empirically based analyses of the links between the quality of the research process and the methods applied on the one hand and the effects achieved on the other.
This paper thus addresses the issue of heightening the societal effects of transdisciplinary sustainability research. The objective is to explore ways of consciously promoting societal effectiveness in transdisciplinary research. We argue that these possibilities evolve at the intersection between the general project framework and an adaptive shaping of transdisciplinary research processes. A reflexive approach of this kind proactively considers the dynamics of interests and concerns, roles and responsibilities, the collaboration culture within a project, and the connectivity to the context of action addressed. Its deployment presupposes an appreciation of the basic conditions, i.e. the historical development of the respective problem, the heterogeneity of actors involved, the general environment and, finally, the funding conditions
Tentative Theses on Transformative Research in Real-World Laboratories: First Insights from the Accompanying Research ForReal
Real-world laboratories are growing in popularity promising a contribution to both: the understanding and facilitation of societal transformation towards sustainability. Baden-WĂĽrttemberg substantially funds real-world labs as part of the initiative "science for sustainability". To facilitate learning with and from these so-called BaWĂĽ-Labs, they are supported by accompanying research conducted by two teams. This article presents first insights and theses on real-world labs as a research format, based in particular on the work of the accompanying research team ForReal. The team supports the labs in their realization and in providing general insights, e.g. by learning from related international research approaches and dialog with international experts, and analyzes suitable quality features and methods (the latter together with the University of Basel team). The theses presented here put up for discussion first insights on real-world labs as a transformative research approach and reflect on them from a theoretical perspective. They illustrate the relevance of a goal-oriented use of methods and present learning processes as core characteristics of real-world labs. The theses were formulated based on discussions with the BaWĂĽ-Labs, exchange in international contexts as well as a thematic literature review
Statistical analysis of pulsed laser beam welding repair strategies of nickel-base superalloys
Pulse shaping is a suitable option to adapt energy input and temperature gradients in the base material during filler wire assisted laser beam welding, although the influence on the temperature-depended microstructure and γ’-precipitation strengthening of Nickel-base superalloys as well as the process windows are not sufficiently understood so far. Therefore, the influence of pulse parameters, preheating temperature, hot-wire heating power and wire feeding rate on the deposition process and the resulting macro- and microstructure of similar Nickel-base superalloy joints of Inconel 738 low carbon (IN 738 LC) with Haynes (HS 282) filler are investigated. The statistical analysis of the multidimensional parameter space with respect to the geometric properties of the weld seams (dilution, aspect ratio and wetting angle) and hot-crack formation revealed high reliability and predictability concerning individual choice of suitable parameters in field repair application
Gyrokinetic simulations of neoclassical electron transport and bootstrap current generation in tokamak plasmas in the TRIMEG code
For magnetic confinement fusion in tokamak plasmas, some of the limitations
to the particle and energy confinement times are caused by turbulence and
collisions between particles in toroidal geometry, which determine the
"anomalous" and the neoclassical transport, respectively. In this work, we
focus on the implementation of neoclassical physics in the gyrokinetic code
TRIMEG, which is a TRIangular MEsh-based Gyrokinetic code that can handle both
the closed and open field line geometries of a divertor tokamak. We report on
the implementation of a simplified Lorentz collision operator in TRIMEG. Since
the code uses an unstructured mesh, a procedure for calculating the flux
surface averages of particle and energy fluxes and the bootstrap current is
derived without relying on the poloidal coordinate, which is useful also for
other simulations in unstructured meshes. With the newly implemented collision
operator, we study electron transport and bootstrap current generation for
various simplified and realistic geometries. In comparison to neoclassical
theory, good agreement is obtained for the large aspect ratio case regarding
the particle and energy fluxes as well as the bootstrap current. However, some
discrepancies are observed at moderate aspect ratio and for a case with the
realistic geometry of the ASDEX Upgrade tokamak. These deviations can be
explained by different treatments and approximations in theory and simulation.
In this paper, we demonstrate the capability to calculate the electron
transport and bootstrap current generation in TRIMEG, which will allow for the
self-consistent inclusion of neoclassical effects in gyrokinetic simulations in
the future
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