Hier finden Sie eine Übersicht der sieben Promtionsthemen, weitere Informationen zu den Betreuungs-Tandems (BTU & BAM) und die jeweilige Stellenaussschreibung.

Die Bewerbungsfrist wurde für folgende Stellen verlängert:

  • PhD Topic 3 – Evaluation of the influence of lubricants on pre-ignition of hydrogen for engine relevant conditions (Frist: 17.06.2022)
  • PhD Topic 6 – Influence of manufacturing-induced imperfections on the operational safety of composite H2 pressure vessels (Frist: 03.08.2022)

Für Rückfragen kontaktieren Sie bitte die Ansprechperson des enstprechenden Promotionsthemas (siehe jeweils »Stellenausschreibung und Kontakt«).

PhD Topic 1 – Efficient PMC qualification strategies for next generation H2-pressure vessels Lead: BAM (Ausschreibung geschlossen)

Beschreibung

Pressure vessels in light weight design are manufactured from polymer matrix composites (PMC), mainly from carbon-fibre reinforced plastics (CFRP). While the fibre orientation and strength in fibre direction respects the global stress state and the requirements of the filament wind process, the in-service life is mainly influenced by the inter-fibre failure due to long term and cyclic thermo-mechanical loading under in-service conditions. An increased focus on a circular economy plays a major role in the materials selection process. Hence new polymer-matrix systems and fibre filament sizings have to be designed and qualified. State of the art are uniaxial standard test on flat specimens for material characterization.

In a joint research project between the BTU-Cottbus, institute “Polymerbasierter Leichtbau (PbL)” and BAM FB-5.3, Polymer Matrix Composites”, more efficient concept of testing tubular specimens will be investigated. With continuous fibre reinforced tubular specimens manufactured using the filament winding technique, more realistic multiaxial (tension shear, tension-tension) testing is possible. The inter-fibre failure mechanisms are characterized in-situ with non-destructive testing. Additionally, the tubular specimens can be pre-aged with inner H2-pressure during tensile testing. Finally, due to the opportunity of multiaxial testing the new PMC materials can be qualified for H2 applications using lower number of test specimens in a more realistic and efficient manner. Testing of tubular PMC specimens has not been exhaustively studied to-date due to the fact, that no standardized geometries and test procedures exist. Hence, an additional aim of the project is to build a fundamental basis for an international standard for a tubular specimen geometry used for the characterization of PMC.

Deliverables

  • Design, manufacturing and test of representative tubular specimens
  • Built-up of in-situ H2-pressurized tubes in tensile test
  • Multiaxial test-protocols for standardisation
Stellenausschreibung und Kontakt

Doktorand*in (m/w/d) – Polymer-matrix composites for next generation H2-pressure vessels (PhD Topic 1)

Bewerbungsfrist: 03.06.2022


Kontakt

Prof. Dr.-Ing. Vol­ker Trap­pe 
Fachbereich 5.3 Polymere Verbundwerkstoffe, BAM
Volker.Trappe(at)bam.de
T +49 30 8104-3386

PhD Topic 2 – Novel materials and coatings for the detection of hydrogen and hydrocarbons Lead: BTU (Ausschreibung geschlossen)

Beschreibung

Atomic layer deposition (ALD) is a very promising route to manufacture chemical sensors due to a very high degree of precision with respect to chemical composition and morphology of the active sensor’s surface. The key for using this technology to develop efficient sensor materials for selective and sensitive detection of hydrogen lies in the optimization of this method by applying different analytical tools (e.g., X-ray photoelectron spectroscopy, time-of-flight secondary ion mass spectrometry, focused ion beam and electron microscopy) as part of developing the synthesis process.

The aim of this project is to gain an insight into the materials properties and synthesis process by a unique combination of surface sensitive methods. This insight will allow the characterization of the nucleation and growth process, which needs to be adapted carefully as the materials properties are strongly dependent on the specific choice of precursors employed and their chemical reaction with the substrate as well as remaining contaminants, which might lower the efficiency of the final product. To complement the deposition and analysis techniques, kinetic Monte Carlo (kMC) modelling will accompany the present work. KMC methods are particularly suitable to model ALD processes as the microscopic lattice structure and atomic interactions, as well as microscopic film growth processes are accounted for. When opting for a proper lattice Monte Carlo Model, statements can be made concerning the deposition conditions, the chemical composition of the thin layer, as well as of the surface morphology.

The project is structured as a complete R&D process from production to testing thanks to the collaboration between experts from both BTU Cottbus and BAM and the utilization of state-of-the-art facilities in both institutes.

Deliverables:

  • ALD preparation recipes for the deposition of metal oxide layers tailored to specific sensor requirements
  • Dissemination of characterization and knowledge about the gas-oxide interaction depending on external variables (temperature, pressure, gas composition)
  • Detailed assessment of the sensor response depending on gas composition and exposure

PhD Topic 3 – Evaluation of the influence of lubricants on pre-ignition of hydrogen for engine relevant conditions Lead: BTU (Bewerbung möglich bis 17. Juni 2022)

Beschreibung

The operation of gas engines with green hydrogen from renewable energy sources is a future technology to achieve CO2-neutrality in the energy and transport sector. To increase the thermal efficiency of such piston engines the increase of compression ratio and charging of the intake air are applied. This leads to higher compression pressures and temperatures during the engine operation cycle. Further, to avoid galling and excess thermal stresses of the piston rings and cylinder surfaces, lubricating oils are necessary.

Due to the higher thermal auto-ignition propensity of engine oils compared to hydrogen, the oil can cause self-ignition under certain conditions, leading to low-speed pre-ignition (LSPI) phenomena. The LSPI creates strong pressure gradients within the combustion chamber, which can destroy the components, such as piston and valves. For example, low oil viscosities and high calcium content could enhance high pre-ignition rates. Hence, it is important to improve the knowledge of the impact of lubricant properties on LSPI in hydrogen engines.

In the joint research project between BTU Cottbus-Senftenberg, Chair of “Thermodynamics / Thermal Process Engineering”, and BAM Competence Centre “H2Safety@BAM”, the lubricating oil self-ignition process within hydrogen/air-mixtures will be investigated. Two approaches will be facilitated to investigate the self-ignition process: 1. An experimental investigation of the influence of lubricant oil properties under engine-relevant conditions, 2. A numerical investigation to understand the effects of physical and chemical processes on lubricant oil self-ignition. The results will contribute to the H2 safety for gas engine operation by proposing optimum lubricant properties to avoid LSPI, while ensuring appropriate lubrication.

Deliverables

  • Fundamental understanding of the influence of lubricant properties on the pre-ignition in hydrogen/air-mixtures
  • Validated detailed kinetic model for prediction of pre-ignition in hydrogen/air mixtures and addition of various lubricants
  • Contribution to H2 safety by evaluating optimum properties of lubricants for prevention of pre-ignition in hydrogen engines

PhD Topic 4 – Digital sensor twin for hydrogen applications Lead: BAM (Ausschreibung geschlossen)

Beschreibung

The optimisation and validation of the process management of hydrogen plants with sensor technologies is the main goal of the project. For this purpose, sensor networks with digitally supported data mining strategies are to be intelligently designed (keywords: artificial intelligence AI or digital twin). Many sensors / sensor systems are available as basic components for this purpose, which, similar to the human senses, monitor physical and chemical parameters on and in plants. In conjunction with computer systems with sufficient performance, the detection and interpretation of malfunctions and process monitoring is thus guaranteed. The project brings together technologies from different fields (microsensors, especially digital hydrogen selective gas sensors, temperature, and humidity sensors; low-power radio/wired networking; sensor fusion based on artificial intelligence) and integrates them for the first time into sensor nodes for, e. g. H2 plant monitoring at fuelling stations, that are multifunctional and offer a constant expansion of their functional spectrum through the learning of signal patterns. Since the project is stepping on the simulation knowledge and the exact signal patterns and application cases are not known a priori due to a lack of corresponding experience, an early establishment of sensor nodes in the field is indispensable to be able to gather experience and, above all, concrete data, and demonstrate online evaluation of the data patterns in the sensor network to develop a methodological approach for digital twins which.

Deliverables:

  • Development of a sensor network concept considering literature research, market and patents survey of commercially available sensor elements and detection systems
  • Establishing a sensor node system for monitoring and an apparatus for sensor tests
  • Digital twin for the determination of hydrogen in air
  • Testing of novel H2 sensitive materials and coatings for the investigation of hydrogen distribution in the sensitive layer with generated test gases (connection to topic of novel sensor materials and coatings)
Stellenausschreibung und Kontakt

Doktorand*in (m/w/d) der Fachrichtung Informatik, Prozessanalytik oder vglb. (PhD Topic 4) 

Bewerbungsfrist: 03.06.2022


Kontakt

Dr. rer. nat. Carlo Tiebe
Fachbereich 6.4 Materialinformatik, BAM
Carlo.Tiebe(at)bam.de
T +49 30 8104-4518

PhD Topic 5 – Influence of manufacturing process-related residual stresses in wound composite material on the operational safety of H2 pressure vessels Lead: BAM (Ausschreibung geschlossen)

Beschreibung

The storage of hydrogen is essential for the successful implementation of the energy transition and emission-free mobility. Modern type IV pressure vessels essentially consist of a polymer liner and a continuous fibre-reinforced composite deposited on the liner. The composite can be created in the pressure vessel using winding technology, the AFP process (Automated Fibre Placement) or by braiding.

During the production process, the fibres must be placed under pretension. Without suitable countermeasures, this leads to a reduction of the originally introduced residual stresses in the winding process layer by layer. As a result, the different layers of the same direction bear unevenly. This leads to reduced strength and reliability. To prevent this, the liner can be supported by internal pressure in such a way that a uniform pretension and load distribution are achieved across the wall thickness.

For a better understanding of the influence of residual stress and the methods of prevention, these two aspects are to be systematically investigated. For this purpose, extensive simulations of the tank wall and hydraulic tests on a series of model tanks are planned. These model tanks are to be designed and manufactured to the pressure level usual for hydrogen itself and equipped with integrated sensors. The tests will be carried out hydraulically and are to be statistically evaluated. The doctoral thesis described in this way is intended to describe the influence of the residual stresses caused by the manufacturing process on the operational safety of H2 storage tanks and concrete approaches for avoiding these imperfections. Within the scope of the described doctoral thesis, it is intended to describe the influence of the residual stresses caused by the manufacturing process on the operational safety of H2 storage systems and to demonstrate an approach for avoiding these imperfections.

Deliverables:

  • Description of the FE-model of the model composite pressure vessel including the winding and curing process under consideration of a controlled internal pressure in the liner
  • Determination of the design and the manufacturing process (filament winding and AFP process) of model composite pressure vessels including the targeted parameters
  • Implementation and application of a suitable test setup with integrated SHM system
  • Report on the findings, including the impact of internal stresses by internal pressure on strength and reliability aspects.

PhD Topic 6 – Influence of manufacturing-induced imperfections on the operational safety of composite H2 pressure vessels Lead: BTU (Bewerbung möglich bis 17. Juni 2022)

Beschreibung

The storage of hydrogen is essential for the successful implementation of the energy transition and emission-free mobility. Modern type IV pressure vessels essentially consist of a polymer liner and a continuous fibre-reinforced composite deposited on the liner. The composite can be created in the pressure vessel using winding technology, the AFP process (Automated Fibre Placement) or by braiding.

During the manufacturing process, imperfections are introduced into the composite pressure vessels, which can lead to a significant reduction in operational reliability.

In order to increase the lightweight level of H2 pressure vessels and to increase their reliability, knowledge about the influence of manufacturing imperfections on the operational safety of H2 pressure vessels is essential.

In the joint research project between the BTU-Cottbus, Chair of “Polymer-based Lightweight Design (PbL)” and BAM Divisoon-3.5, “Safety of Gas Storage Systems”, it will be possible to demonstrate the influence of manufacturing-related imperfections as a function of the material combination used on the operational reliability of H2 storage tanks by means of extensive structural tests. The scientific issue is considered using two approaches: The verification of critical, manufacturing-induced imperfections and the derivation of corresponding recommendations for vessel design and manufacturing. In addition, the increase of operational safety through the optimization of a new material combination based on a fracture toughness-modified thermoset matrix system with thereby increased tolerance against damage initiation by manufacturing-induced imperfections.

Deliverables:

  • Development and manufacturing (filament winding and AFP process) of a representative composite test specimen with targeted  imperfections
  • Implementation and application of a suitable test setup with integrated SHM system
  • Description of the FE-model of the model composite test specimen including manufacturing-induced imperfections
  • Derivation of design rules and new material concepts (fracture toughness modification)
  • Report on the findings, including the impact of manufacturing-induced imperfections on the operational safety and Derivation of design rules and material concepts

PhD Topic 7 – Influence of fires on tanks for cryogenic fluids Lead: BAM (Ausschreibung geschlossen)

Beschreibung

Liquid hydrogen (LH2) is seen as the most important transport mode on the way to establishing hydrogen (H2) in the energy industry. In addition, LH2 has the long-term potential to become the energy carrier for energy-intensive sectors of the economy, such as heavy-duty transport.

Transport and storage of LH2 occur at temperatures below -240°C and typically at overpressures. The development of suitable systems for this purpose is highly interdisciplinary and involves a great deal of technical effort. Commercial products for this purpose were developed particularly with the mid-20th century emergence of the liquefied natural gas (LNG) market, which requires similar technical solutions. Various suitable technologies were developed, driven by the steadily increasing demand over the last decades and the economic efficiency of the transport systems of LNG.

The situation is different concerning safety. So far, this has only been addressed in a few studies, so there are numerous gaps in knowledge that need to be filled. The focus of the project is to investigate the influence of fires on tanks for cryogenic fluids. For this purpose, research is to be carried out on:

  • how fires affect super insulation,
  • how fires affect a cryogenic hazardous material in such a tank,
  • which models can be used to calculate such incidents.
Stellenausschreibung und Kontakt

Doktorand*in (m/w/d) der Fachrichtung Maschinenbau, Thermodynamik, Werkstofftechnik, Verfahrenstechnik oder vergleichbar (PhD Topic 7) 

Bewerbungsfrist: 03.06.2022


Kontakt

Prof. Dr.-Ing. Frank Otremba
Fachbereich 3.2 Gefahrguttanks und Unfallmechanik, BAM
E Frank.Otremba(at)bam.de
T +49 30 8104-1320