Open Access

The integration of EN AW 7075 aluminium in Body in White structures is a promising way to achieve weight savings, which in turn can make a significant contribution to reducing CO2-emissions. However, due to hot cracking susceptibility, conventional welding technologies offer limited possibilities to join the material. Therefore, laser beam welding in vacuum is introduced as a comparatively new joining technique. The investigations show, that it is possible to weld the EN AW 7075 alloy in an overlap joint configuration without pores or microcracks appearing in the weld seam. The weld seam has a very fine-grained structure, which presumably has a favourable effect on hot cracking mechanism. The prevention of cracking is likely due to the lower temperature gradient between the capillary wall and the fusion line caused by the low evaporation temperature due to the reduced pressure. The reduced temperature results in lower residual stresses, which presumably has a positive effect on the tendency to hot cracking. In addition, the fine-grained structures can absorb strain better than coarse grain structures, that usually occur in conventional laser beam welding.

Industrial communication at the field level is highly dependent on the standards and their implementation on industrial PCs and Programmable Logic Controllers. The integration of industrial sensors and actuators requires manual configuration by plant operators and automation engineers. Nowadays interoperability plays an important role in Industry 4.0. For this the OPC UA Foundation and Platform Industrie 4.0 organization have published the Field Device eXchange and Asset Administration Shell standards, respectively, to define interoperable metadata models. However, there is no single way to define a field device metadata model and reuse it with other systems. This leads to heterogeneous data models and a lack of agreement on a generic semantic model for field devices. In this paper, we propose the Industry 4.0 Field Device Ontology to enable an interoperable semantic definition of field devices. The goal of this ontology is to reuse existing information from field devices, such as device description files, device profiles, and their application data. This paper covers the design of the ontology to enable semantic interoperability of field devices, the generalization of application data, and its implementation with the OWL 2 Web Ontology Language. The main contribution of our work is to provide the basic building blocks to enable the development of interoperable field device applications and integration with Industry 4.0 information model standards.

In dieser Arbeit wird der Entwicklungprozess und die Validierung einer CI/CD-Pipeline für die Umfeldsensorik von Schienenfahrzeugen untersucht. Das Ziel ist, die Umsetzbarkeit der CI/CD-Pipeline unter Verwendung von Normen für die Anforderungen an die Softwareentwicklung in Bahnanwendungen zu prüfen und zu evaluieren. Hierbei werden Anforderungen auf Systemebene, Architektur und Komponentendesign definiert, die nach der Implementierung innerhalb der CI/CD-Pipeline auf ihre Korrektheitüberprüft werden. Mithilfe vordefinierter Fehlermetriken werden die Anforderungen der verschiedenen Phasen der Softwareentwicklung innerhalb jeder Teststufe verifiziert. Die Verwendung einer Simulationsumgebung für Schienenfahrzeuge zur Validierung der Systemanforderungen innerhalb der CI/CD-Pipeline wird zusätzlich überprüft. Die Ergebnisse zeigen, dass insbesondere die Installation von Abhängigkeiten, der Build- Prozess des Projekts, die Verifizierung der Modulanforderungen sowie die Bereitstellung der Software mittels Docker-Image erfolgreich automatisiert werden konnten. Die Integrationsund Systemtests zur Verifizierung der Architektur und Validierung des Gesamtsystems stellten sich jedoch aufgrund der hohen Komplexität als besonders herausfordernd bei der Umsetzung heraus. Insbesondere rechenintensive Prozesse wie die Validierung der Systemanforderungen mittels Simulation erwiesen sich als ressourcenintensiv, sodass eine Parallelisierung innerhalb der CI/CD-Pipeline nur mit zusätzlicher Hardwarekapazität realisierbar ist.

Thanks to its hollow shape and fibre-matrix material structure bamboo is an excellent light weight engineering material. Combined with the high availability and carbon sequestration potential, it represents a sustainable alternative for non-renewable resources like metals and plastics. The fast-growing plant produces mechanically strong culms with a flexural modulus-to-density ratio similar to aluminium. Existing applications use full culm bamboo as rods or beams in load-bearing structures. Typical examples are handmade construction applications and consumer goods such as bicycles. However, hardly any industrialized applications of bamboo culms can be found, especially in Europe. The development of design standards and the cultivation of bamboo in Europe might help to increase the use of bamboo as an engineering material. Nevertheless, there is a particular lack of scalable processing methods for bamboo culms. This is due to missing quality assurance, reliable handling and load-bearing joining methods for the naturally varying bamboo culms. The research project 'BambusFAB' focuses on these methods and integrates them into an automated, scalable production line. In three main steps, the production line processes individual bamboo culms and produces structures of various bamboo products. In the first step, the geometric properties, namely the outer contour of the bamboo culm, are determined by non-contact 2D laser triangulation and 2D digital image correlation. In addition, the bending stiffness curve of the culm is measured in a non-destructive 4-point bending test. In the second step, an algorithm uses the data obtained to determine pieces of the bamboo culms and to assign them to their most useful position in the given structures. The algorithm evaluates factors such as the outer diameter, bending stiffness, out-of-straightness and minimum offcuts. In the third step, the cut bamboo pieces are assembled in an automated frame jig by means of force-sensitive robot manipulation. The bamboo pieces are connected quickly and easily using a novel adhesive joining method, which additionally can be adapted to the outer contour of the bamboo piece by using an automated 3D printing workflow. As part of the research project, both a bamboo bicycle and a stroller frame are being built as use cases.

Interoperability at the field level is dependent on the specific technology implementation and its semantics. Integrating field devices with different communication protocols is not a simple process, as there is no direct semantic mapping between them. In recent years, standards such as the OPC UA Field eXchange and the Asset Administration Shell have proposed neutral data models to reduce the heterogeneity of field device semantics. However, to integrate different field device standards, a formal mapping between the semantic terms of these standards and the neutral data models must still be defined. A research topic that remains open is how different standards can be automatically mapped to a neutral interface independent of their implementation. In this paper we present a novel approach that generalizes the semantics of field devices at the communication level, enabling the use of inference rules that are independent of specific standards. Our method, based on the Industry 4.0 Field Device ontology, identifies the generic type of any field device and provides an interoperable capability description adaptable to various protocols. The framework includes a semantic broker that automates the creation of device instances, executes inference requests, and generates a generic semantic model for field devices. The objective of this work is to simplify the integration of field device semantics, with a generalization of the application layer and facilitate their mapping to other higher-level data models.