What is OPUS?
Siegen University Library provides a free of charge repository named OPUS Siegen (OPUS = Online PUblication Server) with the purpose to publish, archive and retrieve electronical documents produced at the University of Siegen.
What will you find here?
You will find Open-Access-Publications from all faculties of Siegen University and from the "universi" publishing house. The University Library applies acknowledged quality standards and offers support for publishing your documents.
How to participate?
For uploading documents, sign on to OPUS via Shibboleth using your ZIMT-Account.
Recently published
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Publication Open Access Die Rolle kollektiver Identifikation für den Erfolg geopolitischer Strategien(2025-05-07)A newly developed research concept aims to close an important research gap in geopolitics and political geography. The focus is on comparing the geopolitical resources of different states and geographical regions, determining the intensity of collective identification with geographical regions, and empirically investigating the implementation of hard and soft power. Based on various research hypotheses, the research concept is applied to several empirical case studies.Source Type: - Some of the metrics are blocked by yourconsent settings
Publication Open Access Kämpfe um Fiktionen. Mithu Sanyals „Identitti“ zwischen Populärem Realismus und Postautonomie(2026-05-07)This article examines the tension between authorship and identity in works of Popular Realism, using Mithu Sanyal’s novel “Identitti” as a case study. At its core is the question of the extent to which the identity of authors and their (potential) experience of and exposure to marginalization function as a criterion for legitimacy and as a determinant of popularity. The starting point for these reflections is a critical engagement with Moritz Baßler’s concepts of Popular Realism and New/Modern Midcult. A brief analysis demonstrates how these concepts can be applied to Sanyal’s novel, and the points of criticism identified in this context – particularly the insufficient separation of ethics and aesthetics – lead to a plea for a post-autonomous perspective. In this perspective, the intertwining of ethics and aesthetics as well as the authorization to narrate are recognized as a specific potential of contemporary literature. - Some of the metrics are blocked by yourconsent settings
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Publication Open Access 1 3 - Some of the metrics are blocked by yourconsent settings
Publication Open Access Design and Development of Hybrid Tools for Rotary Draw Bending Using Digital Twin and Additive Manufacturing Processes(2026)Rotary draw bending (RDB) process is a profile bending process mostly used in industrial practices for bending metal tubes. Presently, RDB process is conducted by using geometry specific bending tools. The fundamental tools used in RDB process are pressure-die, bend-die, clamp-dies, wiper-die, collet and mandrel. These tools have simplified geometries with a semi-circular tool surface which corresponds to only one specific tube diameter. This makes RDB process inflexible because different tube diameters cannot be used with a specific set of bending tools. In addition to process-flexibility, the modern production regime of present era needs bending tools to be cost effective and light weight. This doctoral thesis is aimed to utilize modern manufacturing techniques, i.e., 3D printing processes and digital twin of RDB process, to develop the geometric design of bending tools which should be cost effective, light weight and provides process-flexibility to RDB process. A digital twin of the RDB process is developed and the accuracy of the digital twin is verified by comparing the FE-simulation results with practically conducted experiments. The design factors which critically influence the tool design are identified through digital twin prototyping. The digital twin prototyping method encompasses systematic development and testing of 3D printed polymeric tools in RDB process. Topology optimization of a conventional tool geometry is conducted in order to identify minimum material required within the tool. The results obtained from digital twin prototyping and topology optimization envisioned the development of a hybrid tool. A hybrid tool consists of two different materials i.e., polymers and metals. The materials of a hybrid tool are selected from Ashby material charts on the basis of requirements resulting from process parameterization and topology optimization. A model of the hybrid tool is developed according to material properties of selected materials and identified tool design factors. The model is imported in digital twin of RDB process and tool performance is investigated by conducting process simulations with different tube diameters. After obtaining process feasibility through digital twin, the hybrid tool consisting of polymer - PLA and metal - stainless steel is practically 3D printed and experimentally tested in an actual RDB process. The experimental results demonstrates that a 3D printed hybrid tool is capable of conducting bending operations with different tube diameters while enabling significant material saving within the tool. A comparison is made between the novel 3D printed hybrid tools and conventional steel tools. A design formula is presented that determines the efficiency of bending tools through Tool Efficiency index (TEi). For practical applications, the geometry of 3D printed hybrid tools is standardized through aspect ratio and corresponding upscale size factors.4 7

