Alexander Stolz

Alexander Stolz
Fraunhofer Institute for High-Speed Dynamics, Ernst-Mach-Institut | EMI · Safety Technologies and Protective Structures

Dr.-Ing.

About

116
Publications
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625
Citations

Publications

Publications (116)
Article
Full-text available
Fatally injured vulnerable road users, especially pedestrians who collided with motorised vehicles, account for 31% of all recorded fatalities in urban traffic in the EU. Autonomous vehicles will improve this situation in the future, reducing the impact of the human factor in critical traffic situations. The development of autonomous driving functi...
Article
Full-text available
The growing variety of transportation options and increasing traffic congestion pose new challenges for road safety. As a result, there is an intensified focus on developing automated driving features and assistance systems aimed at minimizing accidents caused by human errors. The creation of these systems requires a substantial amount of testing k...
Article
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This paper presents a semi-automated approach for assessing building vulnerability on an urban scale, specifically focusing on floods and heavy rainfall events. The method involves three steps: categorization of buildings using open geodata, development of parametric building models for each category, and probabilistic analysis to generate fragilit...
Article
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The behavior of road or perimeter protection barriers under vehicle impact are usually investigated based on crash tests and finite element (FE) numerical approaches, which are ether expensive or time-consuming. Several studies have proposed to reduce the computation time of the numerical analysis by substituting the complex FE models of vehicles u...
Article
In an online survey, 154 decision-makers from the food industry were asked about resilience management, coping with disruptions, resilience characteristics, resilience dimensions and investment needs in their companies. This article analyses the survey, presents methods for assessing resilience and identifies potential for improvement. 84% of those...
Article
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A clear procedure for determining the performance of vehicle security barriers (VSB) will aid event planners and security forces in selecting an appropriate type of VSB and placing it at a safe distance from the crowd. This paper presents a numerical analysis procedure for precisely determining the penetration distance of vehicles running over VSBs...
Article
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A rheological model is proposed that captures the performance loss and properties of a potential subsequent recovery of socio-technical systems subject to arbitrary disruptions. The model facilitates the quantitative assessment of such systems’ resilience. While most models known from the literature describe systems that fully recover from aforemen...
Conference Paper
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Despite being at the two edge of soil dynamics, blast and earthquake engineering find a common ground by looking for solution able to develop resilient structures and infrastructures. In this field, the soil structure interaction (SSI) and the development of constitutive models, especially for geomaterials, play a significant role. Moreover, experi...
Conference Paper
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Due to the increase in the frequency and intensity of natural disasters such as heavy rainfall events, the evaluation of the vulnerability of the built environment is becoming increasingly important. Evaluation techniques for each separate building often require detailed geometric models of the supporting structures and time-consuming simulations....
Preprint
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Angle-of-Arrival estimation technology, with its potential advantages, emerges as an intriguing choice for indoor localization. Notably, it holds the promise of reducing installation costs. In contrast to ToF/TDoA based systems, AoA-based approaches require a reduced number of nodes for effective localization. This characteristic establishes a trad...
Conference Paper
The resistance of bedded or earth-covered civil engineering constructions to soil penetration, buried explosion or mine blast is governed by the dynamic mechanical properties of all soil layers involved. In this context, two different granular materials are characterized under high rate loading. The strain rates range from quasi-static (10-5 s-1) t...
Article
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The present work describes the characterization of two different granular materials, a fine cohesive and a coarse cohesionless soil, with regard to their behavior under high-rate loading. The conditions range from quasi-static ( 105 s −1 ) to dynamic strength ( 102 s −1 ) using a standard press and a Split-Hopkinson Bar (SHB) with a triaxial pressu...
Article
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Angle-of-Arrival (AoA) estimation technology, with its potential advantages, emerges as an intriguing choice for indoor localization. Notably, it holds the promise of reducing installation costs. In contrast to Time-of- Flight (ToF)/Time-Difference-of-Arrival (TDoA) based systems, AoA-based approaches require a reduced number of nodes for effective...
Conference Paper
In case of an explosion event, in addition to the direct risk from the blast wave, secondary risks arise from component debris ejected from an affected structure. In particular, concrete and masonry wall elements represent a potential hazard because they show a high degree of fragmentation when exposed to an extreme load (e.g. blast waves, contact...
Article
<Pipeline networks are an efficient and widespread transportation system for supplying natural gas as well as increasingly green gas to Europe. However, they are exposed to risks arising from environmental factors, accidents, crime and political issues. This work contributes to the assessment of gas transmission networks and enables a targeted impr...
Conference Paper
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Risk control and resilience of critical infrastructures (CI) and similar cyber physical socio technical systems are increasingly requested by legal regulations and emerging technical standards at international, European (ECI) and national levels, e.g. the German KRITIS umbrella law. Along with the increase of knowledge, the number of methods for CI...
Conference Paper
Sparse arrays have the ability to estimate the Direction-of-Arrival (DoA) of more sources than available sensors by placing sensors in a specific geometry. This reduces the hardware complexity, respectively provides the possibility of estimating a large number of concurrent sources. In this contribution we present a measurement platform to experime...
Article
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Border control systems at Europe’s Schengen (and worldwide) borders are necessary to mitigate cross-border threats, but are perceived as free-traveling bottlenecks. Today’s applicable European regulations demand rule-based control schemes and do not allow risk-based elements. A policy shift towards risk-based border control has been considered in s...
Conference Paper
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Autonomous driving has been among the most actively researched topics over the past decades. Today, automotive vehicles are already equipped with driving assistance systems with partial autonomous driving capabilities. Thus, the need for quantitative and qualitative assessment of automated driving functions becomes increasingly vital. The used hard...
Article
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An anticipated challenge for the offshore wind industry is the legally standardized decommissioning of offshore wind infrastructure after the expiration of the respective approval period. To meet the energy and climate targets set by, e.g., the German Federal Government, this challenge must be mastered in the context of sustainability. Potential co...
Chapter
The work focuses on the impact of disruptions on a railway transportation network. The modeling of the transportation network with the help of graph theory is presented and criticality/vulnerability assessment and impact propagation in these networks is studied. Furthermore, the work emulates defined mitigation measures in the modelled network and...
Chapter
In the EU project SAFETY4RAILS, the project partners developed a collaborative toolkit that is able to assess and eventually improve the resilience of rail and metro transportation and its infrastructure against various cyber, physical and combined cyber-physical threats. In general, to improve a property of a system such as resilience, it is neces...
Article
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Offshore wind energy (OWE) production is a crucial element for increasing the amount of renewable energy. Consequently, one can observe a strong and constant rise of the OWE industry, turning it to an important contributor of national energy provision. This trend, however, is accompanied by increasing pressure on the reliability, safety, and securi...
Article
Bonn / Dresden / Freiburg. Globale Lieferketten der Agrar- und Ernährungsindustrie werden immer wieder durch disruptive Ereignisse wie dem Angriffskrieg Russlands auf die Ukraine oder Umweltkatastrophen nachhaltig beeinträchtigt.
Chapter
Terrorism is first and foremost viewed as a matter of security policy; however, its emergence, perception, effects, prevention and mitigation actually involve a multitude of societal sectors as well as academic fields, which also means that numerous academics, practitioners and decision-makers are in a position to contribute to analysing and counte...
Book
Vergangene und aktuelle Ereignisse untermauern die Tatsache, dass terroristische Angriffe zwar statistisch selten sind, jedoch schwerwiegende Konsequenzen haben, wenn sie Wirklichkeit werden. Neben personellen Schäden führen auch potentielle Schäden an Gebäuden zu einer zusätzlichen Gefährdung für Personen. Nicht zuletzt wird auch die Gebrauchstaug...
Article
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Blast loading scenarios and the corresponding hazards have to be evaluated for infrastructure elements and buildings especially at industrial sites for safety and security issues. Point fixed corrugated metal sheets are often applied as façade elements and can become a hazard for humans if they are pulled off. This paper investigates the dynamic be...
Chapter
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Increasing the safety and security of critical infrastructure in Europe is the overarching goal that underlies this work. It presents a Conceptual Model (CM) enabling a comprehensive and structured description of critical infrastructure systems as well as the derivation of Concept of Operations (CONOPS). Hereby, the CM is based on definition of sys...
Article
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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 contro...
Article
Rising extremes and varieties of threats towards socio technical systems ask for improved overall risk control and resilience enhancement. Most current classical approaches focus on the assessment of single or multiple threat events countering system objectives. However, more recent approaches ask for the identification, determination and use of ti...
Conference Paper
As extreme weather events become more frequent and world's population is growing an increasing number of built areas and critical infrastructure networks are challenged by natural hazards like heavy rain, urban flooding or landslides. At the same time, the quantity and quality of remote sensing data delivering earth observation products is continuo...
Conference Paper
Questions and answers are a fast way to assess complex day-to-day situations. They can be adopted to the framing conditions and are path-dependent, allowing in-depth analysis of critical issues. Questionnaires try to take up the natural setting using pre-defined sets of questions that cover an area. Often, for comparison of results, they use fixed...
Conference Paper
Natural Gas consumed in Europe is mainly imported via pipelines from Russia, Norway and Algeria. Disruption to the gas network can have serious impact on the supply of gas to the consumers within the gas network and therefore should be prevented. In order to make the European gas network more resilient to disruptions due to various causes predictiv...
Conference Paper
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A growing number of consumer and industrial functionalities, including safety relevant and safety critical functions and services, rely on reliable and resilient telecommunication infrastructures. As telecommunication grids advance virtualization, are designed resembling the internet and are moving towards 5G, the interest to quantify their resilie...
Article
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Followed by the 9/11 attacks in 2001 and the subsequent events, terrorism and other asymmetrical threat situations became increasingly important for security-related efforts of most western societies. In a similar period, the development of data gathering and analysis techniques especially using the methods of machine learning has made rapid progre...
Conference Paper
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The Fraunhofer EMI shock-tube facility “Blast-STAR” is used to simulate blast loadings from high explosive detonations similar to realistic conditions. Mainly tests on explosion-resistant safety glazing and façades are carried out. Due to the extreme conditions during the test, it is not trivial to accurately analyze the specimen reaction and in pa...
Chapter
The resilience analysis performed in RESISTO follows an enhanced risk and resilience management process based on the ISO 31000 risk management standard . The main inputs needed for the resilience quantification are gathered at separate steps of the management process: a precise understanding of the system context and the system itself including all...
Article
The failure of structural components, e.g. masonry walls, due to accidental or intentional explosions exhibits a considerable risk to the health of persons, operational safety, and surrounding structures. The debris throw originating from overloaded structural elements poses a significant threat to structures and persons in the surrounding environm...
Conference Paper
Engineering approaches, like single degree of freedom (SDOF) models, can give fast and effective decision support to estimate the damage behavior of structural elements subjected to blast loading. The results can be integrated into risk and resilience methods to evaluate the effectiveness of security measures against such loading cases. The softwar...
Article
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The hazard to persons and structures derived from secondary explosion effects, associated with blast loads on structural components resulting in e.g. debris throw, may exceed the hazard range from the blast wave itself. The debris throw hazard potential is related to the initial fragment throw parameters as launch velocities, angles and masses duri...
Article
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The present paper describes essential results of comprehensive experimental investigations of the analysis of rc‐slabs under impact loads. The presented work was done in collaboration between the Fraunhofer Institute for High‐Speed Dynamics – Ernst‐Mach‐Institut (EMI) and the Technical University of Dresden (TUD) in the national research project “i...
Conference Paper
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The use of the Split Hopkinson Pressure Bar (SHPB) for the dynamic characterization of materials under high strain rates is well established. It is used to characterize the response of materials under tensile, compressive and shear loadings, with strain rates from 100 – 104 s-1 among other configurations. But, through all these possibilities, contr...
Chapter
The protection of buildings and infrastructure against highly dynamic loadings caused by explosions requires a profound analysis of the dynamic structural and material behavior. High speed recording devices are a valuable instrumentation to support the respective studies. The present chapter gives different examples that emphasize the importance of...
Conference Paper
Quantitative risk analysis (QRA) procedures require classifying the level of damage a building will or has sustained after an extreme loading event such as an explosion. Prior to an explosive event, such an assessment helps identifying weak spots in need of strengthening. In post-explosion analysis, QRA supports first responders by pinpointing buil...
Conference Paper
Bauwerke können durch dynamische Anregung wie bei seismischer Einwirkung extrem belastet werden. Die potentiellen Auswirkungen von Erdbebenszenarien werden im Rahmen von Risikoanalysen betrachtet, um die mögliche Gefährdung einschätzen zu können und gegebenenfalls Gegenmaßnahmen einzuleiten. Die Belastung der einzelnen Bauteile durch seismische Ere...
Article
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## Proceedings of ICSMESP 2017 - International Conference on Structural and Mechanical Engineering for Security and Prevention 2017, 14-16 June, Prague, CZ ## The determination of the blast protection level of civil engineering buildings components against explosive effects represents a topic of crucial importance, in current practice. However, so...
Article
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The Riedel–Hiermaier–Thoma model, which is available in ANSYS Autodyn since 2000 as a description of concrete and similar geological materials in highly dynamic loading situations, has recently been implemented in the multi-purpose Finite Element code LS-DYNA. This article gives a brief overview of the physical details and verifies the new implemen...
Article
Zur Einschätzung von Gebäudeschäden nach möglichen Extrembelastungen infolge außergewöhnlicher Einwirkungen wird ein auf physikalischen Modellen basierendes Ingenieurverfahren vorgestellt, das es erlaubt, auf Grundlage initialer Einzelbauteilschädigungen den zu erwartenden Gesamtgebäudeschaden semi-quantitativ zu beschreiben. Hierzu wurden für vers...
Conference Paper
Multifunktionale Großbauwerke stellen Planer und Ingenieure aufgrund ihrer Dimensionen und ihrer heterogenen Nutzung vor große Herausforderungen gerade in Bezug auf Sicherheit, Robustheit und Resilienz. Für multifunktional genutzte, repräsentative Gebäudekomplexe in urbaner Umgebung werden in Übersicht Planungsgrundlagen bereitgestellt, sodass dies...
Chapter
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Based on representative challenges of sustainable, efficient and resilient and systems, a working definition of Resilience Engineering is provided. It is used to derive five objectives of Reslience Engineering: (A) technical-engineering approach, (B) extension and where appropriate replacement of (classical) risk approaches, (C) seamless extensions...
Article
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Das Verständnis von Impaktvorgängen auf Stahlbetonstrukturen ist von grundlegender Bedeutung für die Auslegung von Bauwerken in Hinblick auf die Bewertung außergewöhnlicher Belastungssituationen, wie beispielsweise Steinschlag oder aber Fahrzeug‐ oder Flugzeuganprall. Bei hohen Verzerrungsraten, die sich bei derartigen Belastungen im Bauteil einste...
Article
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The need for the assessment of structures subjected to natural and man-made hazard scenarios is steadily increasing. The analysis of a building structure with regards to potential progressive collapse as the result of a single hazardous event requires the realistic assessment of the residual capacity of structural members after the initial event. C...
Article
Alongside the accidental release of potentially hazardous substances, incidents evolving around the physical aspects of explosions are the second most reported type of hazard in the processing industry (ZEMA, 2002). The sudden failure of a component processing combustible gases exhibits a considerable risk to the operational safety of the affected...
Technical Report
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The determination of the blast protection level of laminated glass windows and façades is of crucial importance, and it is normally done by using experimental investigations. In recent years numerical methods have become much more powerful also with respect to this kind of application. This report attempts to give a first idea of a possible standar...
Article
Full-text available
Resilience engineering can be defined to comprise originally technical, engineering and natural science approaches to improve the resilience and sustainability of socio technical cyber-physical systems of various complexities with respect to disruptive events. It is argued how this emerging interdisciplinary technical and societal science approach...
Conference Paper
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Since buildings are not exclusively subjected to quasi-static and classical dynamic loads, such as wind loads or earthquakes, but also impact loads caused by vehicles or even airplanes, a good understanding of the structural behaviour and the resulting damage of reinforced concrete structures under such scenarios is of high importance. Methods for...
Article
The analysis of the resistance of structural components to explosive loading conditions is important for the design and assessment of buildings which are potentially exposed to explosions. Explosive loading conditions may arise from sabotage, terroristic attacks or accidental explosions and pose a significant hazard. The characteristics of explosiv...
Article
The most-widely used approach to explosion consequence analysis is the classical engineering method based on the combination of TNT equivalence, scaled distances and overpressure-based damage levels. This approach rests on established and easily comprehensible elements and permits a fast assessment of explosion consequences. There are however sever...
Article
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Special Issue "Advancements in Design, Analysis, and Retrofitting of Structures Exposed to Blast" The determination of the blast protection level of laminated glass windows and facades is of crucial importance, and it is normally done by using experimental investigations. In recent years numerical methods have become much more powerful also with r...
Technical Report
Full-text available
It is important to protect critical buildings (shopping centres, government buildings and embassies), infrastructure and utilities, train and underground stations from being damaged, destroyed or disrupted by deliberate acts of terrorism, criminal activity and malicious behaviour. Normal regulations and building guidelines do not generally take int...
Conference Paper
Full-text available
The accidental detonation of ammunition stacked inside a storage enclosure can have disastrous effects. Additional to the related blast wave, the potential damage caused by debris throw is significant. Not only is the human body more vulnerable to flying debris than to air-pressure waves, but the unobstruct-ed ejection can extend into distances far...