Wissenschaftliche Publikationen "Messtechnik + Simulation"

Zur Indoor-Navigation, die Anwendung in Intralogistik, Produktion und bei autonomen Systemen findet, wurden Methoden zur Verringerung der Störanfälligkeit untersucht. Mit drei verschiedenen Teilsystemen, nämlich Lokalisierung durch Ultraschall, Ultraweitbandfunk und Bildverarbeitung, wurden verschiedene Maßnahmen zur Sensordatenfusion erprobt, um die Performance zu steigern. Dabei diente das von Hahn-Schickard entwickelte Resilienzmaß technischer Systeme zur quantitativen Beurteilung. Die Teilsysteme wurden zunächst einzeln unter verschiedenen Störszenarien getestet. Danach fand eine Datenfusion aus Ultraschall- und Funklokalisierung mit den gleichen Störungen statt; zudem eine Dreierfusion, bei der die Bildverarbeitung hinzukam. Als Alternative zur Datenfusion diente eine mathematische Modifikation der Ultraschalllokalisierung, d.h. eine Arkustangens-Gewichtung der Störungen. Sie erbrachte im Vergleich zur Datenfusion eine annähernd gleiche Resilienzsteigerung, stellte aber im Sinne einer Kosten-Nutzen-Analyse den geringeren Optimierungsaufwand dar.

Organizational and technical approaches have proven successful in increasing the performance and preventing risks at socio-technical systems at all scales. Nevertheless, damaging events are often unavoidable due to a wide and dynamic threat landscape and enabled by the increasing complexity of modern systems. For overall performance and risk control at the system level, resilience can be a versatile option, in particular for reducing resources needed for system development, maintenance, reuse, or disposal. This paper presents a framework for a resilience assessment and management process that builds on existing risk management practice before, during, and after potential and real events. It leverages tabular and matrix correlation methods similar as standardized in the field or risk analysis to fulfill the step-wise resilience assessment and management for critical functions of complex systems. We present data needs for the method implementation and output generation, in particular regarding the assessment of threats and the effects of counter measures. Also included is a discussion of how the results contribute to the advancement of functional risk control and resilience enhancement at system level as well as related practical implications for its efficient implementation. The approach is applied in the domains telecommunication, gas networks, and indoor localization systems. Results and implications are further discussed.

 

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Electronic devices and the associated sensors are exposed to increasing mechanical, ther- 12 mal and chemical stress in modern applications. In many areas of application, the electronics are 13 completely encapsulated with thermosets in a single process step using the injection molding tech- 14 nology, especially with epoxy molding compounds (EMC). The implementation of the connection 15 of complete systems for electrical access through a thermoset encapsulation is of particular im- 16 portance. In practice, metal pin contacts are used for this purpose, which are encapsulated together 17 with the complete system in a single injection molding process step. However, this procedure con- 18 tains also challenges because the interface between the metallic pins and the plastic represents a 19 weak point for reliability. In order to investigate the reliability of the interface, metallic pin contacts 20 made of copper-nickel-tin alloy (CuNiSn) and bronze (CuSn6) are encapsulated with standard EMC 21 materials within the scope of this study. The metal surfaces made of CuNiSn are further coated with 22 silver (Ag) and tin (Sn). An injection molding tool to produce test specimens is designed and man- 23 ufactured according to the design rules of EMC processing. The reliability of the metal-plastic in- 24 terfaces are investigated by means of shear and leak tests. The results of the investigations show 25 that the reliability of the metal-plastic joints can be increased by using different material combina- 26 tions.

Time difference of arrival (TDOA) based indoor ultrasound localization systems are prone to multiple disruptions and demand reliable and resilient position accuracy during operation. In this challenging context, a missing link to evaluate the performance of such systems is a simulation approach to test their robustness in the presence of disruptions. This approach cannot only replace experiments in early phases of development but could also be used to study susceptibility, robustness, response and recovery in case of disruptions. The paper presents a simulation framework for a TDOA-based indoor ultrasound localization system and ways to introduce different types of disruptions.This framework can be used to test the performance of TDOA-based algorithms in the presence of disruptions. Resilience quantification results are presented for representative disruptions. Based on these quantities, it is found that localization with arc-tangent cost functions is approximately 30% more resilient than the linear cost function. The simulation approach is shown to apply to resilience engineering and can be used to increase the efficiency and quality of indoor localization methods.

 

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Hermeticity of an electronic package defines its effectiveness to seal and protect the encapsulated electronics from the ingress of contaminants, gases and moisture, as well as helping avoid toxic materials from inside the capsule contacting tissue. Using accelerated testing by methods of leak detection analysis, the theoretical limit of the lifetime due to water ingress of an encapsulated device can be estimated. However, classical methods are not sufficient for micro-encapsulations and exhibit limitations due to the resolution of the detection mechanisms required for such small cavities. With the availability of cumulative helium leak detection (CHLD) the detection limits can be extended by several magnitudes of resolution. However, limitations due to the physics of leakage apply. This paper discusses the limitations concerning the ability for combined gross, and fine leak testing in combination with outgassing effects using CHLD for miniaturized implantable medical devices. Practical aspects are evaluated regarding the applicability of CHLD for such micro encapsulations at the example of an AuSn sealed alumina package.

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The project “key enabling technologies for clean production” (KET4CP), which is supported by the European Commission, has the aim to connect small and medium-sized enterprises (SME) and Technology Centres (TC) for cleaner, greener and more efficient production. Within this context, SMEs and TCs across Europe work together to establish an open-innovation network and to raise awareness in productivity and environmental performance. This article presents how an open European network of TCs opens its innovation process to support SMEs to become cleaner, greener and more efficient. Furthermore, this article shows how the TCs and SMEs become a part of the open-eco-innovation platform in clean production and how successful the open-eco-innovation process of different European countries is. We revealed that a pan-European open innovation process for eco-innovations with TCs for key enabling technologies (KET TCs) and Enterprise Europe Network partners (EEN) is a successful approach for SMEs that want to produce and develop cleaner products. An application example is mentioned, in which TCs from different European countries have contributed to developing a product of a SME for energy harvesting. The SME, together with the TCs, developed a generator that is installed in city-level water supply pipes and so, it is outstanding in its application. This innovative application is also described in this article.

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When electronic assemblies are experiencing high current loading conditions, thermo-mechanical mismatch induced from the local Joule heating of the component and electromigration (EM)-induced void formation can lead to the failure of the solder interconnect. Scanning electron microscopy (SEM) and electron backscatter diffraction (EBSD) are adopted to investigate the microstructural evolution of solder joints of shunt components subjected to current stressing. Voids and micro-cracks initiate at the corner of solder meniscus, where the maximal divergence of material flux density is located on the basis of finite element method (FEM) simulation. The EM-induced voids introduce higher accumulated plastic strain in the solder joints, which will result in reduction in the lifetime of the electronic assemblies.

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Radio frequency reflectometry is widely used in non-destructive characterization of various materials and can also be applied to automatic impedance matching systems in telecommunication devices. Here, a novel, low cost, software defined approach for measuring the reflection coefficient without using mixers or power detectors is proposed, enabled by using under-sampling down-conversion with an analog-digital-converter. Minimizing the analog part of the system removes possible error sources and a modular design allows application in different fields as well as an implementation as an integrated circuit. Computer simulations as well as measurement results on a printed circuit board setup for a system frequency of 400 MHz are presented, permitting extrapolation to other ultra-high frequencies.

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