TY - CONF A1 - Popiela, Bartosz T1 - Non-Destructive Testing of Type 4 Composite Pressure Vessels N2 - Non-Destructive Testing (NDT) of type 4 composite pressure vessels can be seen as key to better understanding the behaviour of the composite structure and the impact of the manufacturing process on its quality. In this presentation, NDT methods used in the “Trustworthy Hydrogen” project are introduced. A brief discussion of the observed phenomena is provided. T2 - Visit of a delegation from Korea Fire Institute (KFI) CY - Berlin, Germany DA - 24.06.2024 KW - Composite KW - Pressure vessel KW - Non-destructive testing PY - 2024 AN - OPUS4-60401 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Popiela, Bartosz T1 - FEM-Analyse der Reparaturstellen an FKV-Sandwichplatten N2 - Untersuchung des Einflusses des Reparaturpatches auf das Verhalten der reparierten GFK-Sandwichproben unter Zug-, Druck- und Schubbeanspruchung. T2 - 25. Nationales SAMPE-Symposium CY - Kassel, Germany DA - 18.02.2020 KW - Rotorblätter KW - Glasfaserverstärkter Kunststoff KW - Sandwichstruktur PY - 2020 AN - OPUS4-50544 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bernardy, Christopher A1 - Konert, Florian A1 - Popiela, Bartosz A1 - Sarif, Raduan T1 - H2Safety@BAM: Competence Center for safe hydrogen technologies N2 - Presentation of the competence center H2Safety@BAM at the European PhD Hydrogen Conference 2024 in Ghent, Belgium. T2 - European PhD Hydrogen Conference 2024 (EPHyC2024) CY - Ghent, Belgium DA - 20.03.2024 KW - H2safety KW - Hydrogen KW - Safety KW - Competence center PY - 2024 AN - OPUS4-59756 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Popiela, Bartosz T1 - Performance of Type 4 Composite Pressure Vessels: Impact of Residual Stress State N2 - This presentation summarizes the results of an experimental study on slow burst tests, involving two pressure vessel designs with different residual stress states. The significant performance differences between the two designs highlight the critical role of residual stress state in filament-wound structures T2 - Composites Research Seminar at the Innovative Design and Integrated Manufacturing Lab, Seoul National University CY - Seoul, South Korea DA - 22.11.2024 KW - Composite KW - Pressure vessel KW - Residual stresses KW - Burst test KW - Filament winding PY - 2024 AN - OPUS4-61734 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Popiela, Bartosz T1 - BAM 3.5 and Trustworthy Hydrogen: Experimental Investigation of Type 4 Composite Pressure Vessels N2 - The presentation provided a brief introduction to Division 3.5 at BAM and detailed an experimental study of composite pressure vessels as part of the 'Trustworthy Hydrogen' project. It included an in-depth analysis of slow burst test evaluations. T2 - Lab Seminar of IDIM SNU CY - Seoul, South Korea DA - 26.11.2024 KW - Composite KW - Pressure vessel KW - Residual stresses KW - Burst test PY - 2024 AN - OPUS4-61779 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wätzold, Florian A1 - Popiela, Bartosz A1 - Mayer, Jonas T1 - Methodology for AI-Based Search Strategy of Scientific Papers: Exemplary Search for Hybrid and Battery Electric Vehicles in the Semantic Scholar Database N2 - The rapid development of artificial intelligence (AI) has significantly enhanced productivity, particularly in repetitive tasks. In the scientific domain, literature review stands out as a key area where AI-based tools can be effectively applied. This study presents a methodology for developing a search strategy for systematic reviews using AI tools. The Semantic Scholar database served as the foundation for the search process. The methodology was tested by searching for scientific papers related to batteries and hydrogen vehicles with the aim of enabling an evaluation for their potential applications. An extensive list of vehicles and their operational environments based on international standards and literature reviews was defined and used as the main input for the exemplary search. The AI-supported search yielded approximately 60,000 results, which were subjected to an initial relevance assessment. For the relevant papers, a neighbourhood analysis based on citation and reference networks was conducted. The final selection of papers, covering the period from 2013 to 2023, included 713 papers assessed after the initial review. An extensive discussion of the results is provided, including their categorisation based on search terms, publication years, and cluster analysis of powertrains, as well as operational environments of the vehicles involved. This case study illustrates the effectiveness of the proposed methodology and serves as a starting point for future research. The results demonstrate the potential of AI-based tools to enhance productivity when searching for scientific papers. KW - Search strategy KW - Methodology KW - Artificial intelligence KW - Literature review KW - Battery electric vehicles KW - Hydrogen-powered vehicles PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-622012 DO - https://doi.org/10.3390/publications12040049 VL - 12 IS - 4 SP - 1 EP - 16 PB - MDPI CY - Basel, Switzerland AN - OPUS4-62201 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Ghaznavi, Ali A1 - Kästle, Emanuel D. A1 - Popiela, Bartosz A1 - Duffner, Eric T1 - Damage monitoring of hydrogen composite pressure vessels using acoustic emission technique and machine learning N2 - A good understanding of the structural stability of hydrogen composite overwrapped pressure vessels (COPV) is important for the cost-effective design and safe operation of hydrogen storage systems. Acoustic emission (AE) monitoring is a non-destructive method sensitive to microstructural damages such as e.g. fiber breakage, and matrix cracking in COPVs. This study proposes a novel approach for damage monitoring by integrating acoustic emission techniques with machine learning (ML) algorithms to classify and predict damage types in COPVs. However, training accurate classification models requires extensive labeled datasets, which are very challenging to generate due to the nature of AE signal data and the lack of in-situ observations of microscopic failures in COPVs. Our research overcomes this limitation by automating the labeling process of AE signal data for different COPVs using unsupervised ML methods. The most representative features were extracted and then selected from recorded AE signals. Different unsupervised clustering algorithms were utilized based on various extracted feature combinations. The most stable clustering result was achieved and later used as appropriate labels for training classification algorithms. A deep neural network-based deep learning (DL) architecture was used to train discriminative models on AE data, identify patterns, and classify damage types into different classes with improved accuracy and speed for each COPV. Results demonstrate the potential of the proposed combined deep learning approach to train predictive models in identifying failure patterns. The trained models based on individual COPVs show high training, validation, and test accuracy for unseen datasets and offer enhanced predictive capabilities by following advanced DL techniques compared to traditional monitoring methods. The proposed method highlights its potential to improve the efficiency and safety of hydrogen storage systems. T2 - SCHALL 25 CY - Dresden, Germany DA - 26.03.2025 KW - Sequential Neural Network KW - Acoustic Emission KW - Composite Overwrapped Pressure Vessels KW - Damagemonitoring KW - Machine Learning KW - Deep Learning KW - Deep Neural Network PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-629040 DO - https://doi.org/10.58286/30958 SP - 1 EP - 12 AN - OPUS4-62904 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ghafafian, Carineh A1 - Popiela, Bartosz A1 - Trappe, Volker T1 - Failure Mechanisms of GFRP Scarf Joints under Tensile Load N2 - A potential repair alternative to restoring the mechanical properties of lightweight fiberreinforced polymer (FRP) structures is to locally patch these areas with scarf joints. The effects of such repair methods on the structural integrity, however, are still largely unknown. In this paper, the mechanical property restoration, failure mechanism, and influence of fiber orientation mismatch between parent and repair materials of 1:50 scarf joints are studied on monolithic glass fiber-reinforced polymer (GFRP) specimens under tensile load. Two different parent orientations of [-45/+45]2S and [0/90]2S are exemplarily examined, and control specimens are taken as a baseline for the tensile strength and stiffness property recovery assessment. Using a layer-wise stress analysis with finite element simulations conducted with ANSYS Composite PrepPost to support the experimental investigation, the fiber orientation with respect to load direction is shown to affect the critical regions and thereby failure mechanism of the scarf joint specimens. KW - Scarf joint KW - Glass fiber reinforced polymers KW - Failure mechanisms PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-523952 DO - https://doi.org/10.3390/ma14071806 VL - 14 IS - 7 SP - 1806 PB - MDPI CY - Basel, Switzerland AN - OPUS4-52395 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Popiela, Bartosz T1 - Influence of manufacturing process related residual stresses in wound composite material on the operational safety of H2 pressure vessels: PhD Topic Introduction N2 - Short introduction of the PhD Topic 5 in the BTU-BAM Graduate School "Trustworthy Hydrogen". Description of the objectives, deliverables and expected added value of the thesis. T2 - Introduction Week - BTU-BAM Graduate School "Trustworthy Hydrogen" CY - Berlin, Germany DA - 16.01.2023 KW - Residual stress KW - Composite KW - Pressure vessel KW - Hydrogen PY - 2023 AN - OPUS4-56882 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Popiela, Bartosz A1 - Günzel, Stephan A1 - Schukar, Marcus A1 - Mair, Georg W. A1 - Krebber, Katerina A1 - Seidlitz, Holger T1 - Impact of internal pressure control during manufacturing on residual stresses and safety performance of type 4 pressure vessels N2 - Composite pressure vessels are commonly manufactured using the wet filament winding process, where various process parameters can influence the performance of the finished component. In this study two designs of wet filament wound 6.8-liter type 4 composite pressure vessels were manufactured. Both differ only by the internal pressure used during the filament winding, which primarily influences the residual stress state in the composite structure. An extensive experimental study was carried out, including 10 slow burst tests and strain measurements with fiber optic sensors. Significant differences can be observed in the performance of the two designs even though the used stacking sequence, materials and other manufacturing parameters are the same for both designs. A discussion of the differences in the behavior of both cylinder types is provided, including the strain distribution in slow burst tests and failure mechanism. KW - Residual stresses KW - Slow burst tests KW - Filament winding KW - Type 4 composite pressure vessels KW - Hydrogen PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-626663 DO - https://doi.org/10.1016/j.jcomc.2025.100581 SN - 2666-6820 VL - 17 SP - 1 EP - 9 PB - Elsevier B.V. CY - Amsterdam, Netherlands AN - OPUS4-62666 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Popiela, Bartosz T1 - Experimental study on the impact of manufacturing process related residual stresses in wound composite material on the operational safety of H2 pressure vessels N2 - The presentation is an update on the progress of the PhD Project. It focuses on the experimental investigation of the impact of residual stresses on the reliability of type 4 composite pressure vessels. T2 - Summer School 2024 - BTU-BAM Graduate School "Trustworthy Hydrogen" CY - Cottbus, Germany DA - 07.10.2024 KW - Composite KW - Pressure vessel KW - Residual stresses KW - Burst test PY - 2024 AN - OPUS4-61272 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Popiela, Bartosz T1 - Creep Phenomena During Initial Loading of Type 4 Composite Pressure Vessels N2 - A poster presentation on the impact of creep phenomena during initial loading on the safety of type 4 composite pressure vessels. A statistical evaluation of slow burst tests shows an increase of the survival rate of initially loaded composite pressure vessels (sustained load and increased pressure) compared to the ones tested in a brand-new state. T2 - ASME Pressure Vessels & Piping® Conference CY - Quebec, Canada DA - 20.07.2025 KW - Composite KW - Pressure vessel KW - Safety KW - Creep PY - 2025 AN - OPUS4-63761 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Popiela, Bartosz T1 - Modelling of the manufacturing related residual stresses in type 4 pressure vessels for hydrogen storage N2 - Presentation about modelling of the residual stresses in type 4 pressure vessels for hydrogen storage at the European PhD Hydrogen Conference 2024 in Ghent, Belgium. T2 - European PhD Hydrogen Conference 2024 (EPHyC2024) CY - Ghent, Belgium DA - 20.03.2024 KW - Composite KW - Pressure vessel KW - Residual stresses PY - 2024 AN - OPUS4-59757 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Popiela, Bartosz T1 - Impact of the Initial Loading on the Performance of Type 4-CPVs N2 - Poster presentation on the impact of initial loading on the performance of type 4 composite pressure vessels presented at the 4th Netzwerktreffen Leichtbau Berlin-Brandenburg. T2 - 4. Netzwerktreffen Leichtbau Berlin-Brandenburg CY - Berlin, Germany DA - 01.10.2024 KW - Composite KW - Pressure vessel KW - Safety KW - Burst test PY - 2024 AN - OPUS4-61197 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - VIDEO A1 - Popiela, Bartosz T1 - Better with age? Discussion of creep phenomena during initial loading of type 4 composite pressure vessels N2 - A video for the Rudy Scavuzzo Student Paper Competition at ASME PVP 2025. The topic of the presentation is the impact of creep phenomena during initial loading on the safety of type 4 composite pressure vessels. T2 - ASME Pressure Vessels & Piping Conference (ASME PVP 2025) CY - Quebec, Canada DA - 20.07.2025 KW - Composite KW - Pressure vessel KW - Safety KW - Creep PY - 2025 PB - Bundesanstalt für Materialforschung und -prüfung (BAM) CY - Berlin AN - OPUS4-63763 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Popiela, Bartosz A1 - Kim, Kyunghwan A1 - Lee, Kyu-Jin A1 - Lee, Jung-Ryul T1 - Impact of internal pressure regulation in filament winding on the quality of composite cylinders: a study with pulse-echo ultrasonic propagation imaging N2 - To ensure the safety of composite pressure vessels considering the growing usage, this case study investigates how wet filament winding parameters affect quality of composite cylinders. Two 6.8-liter Type 4 cylinders with identical geometry and fiber stacking sequence were analyzed using pulse-echo ultrasonic propagation imaging. One cylinder was wound under constant internal pressure, while the other used increasing pressure to influence residual stress and influence imperfections. This difference led to distinct failure mechanisms in burst tests. The study focused on identifying porosity and resin-rich areas, visualized through ultrasonic wave propagation imaging and variable time-window amplitude mapping. Results revealed that the cylinder wound with increasing pressure had better composite consolidation but more resin-rich areas in the hoop windings. The findings demonstrate the effectiveness of pulse-echo ultrasonic imaging as a non-destructive method for detecting manufacturing-induced imperfections and highlight the importance of optimizing filament winding parameters to enhance composite quality. KW - Composite KW - Pressure vessel KW - Wet filament winding KW - Pulse-echo ultrasonic propagation imaging PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-639801 DO - https://doi.org/10.1080/09243046.2025.2547457 SN - 1568-5519 SP - 1 EP - 18 PB - Taylor & Francis AN - OPUS4-63980 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Popiela, Bartosz A1 - Günzel, Stephan A1 - Mair, Georg W. A1 - Seidlitz, Holger ED - Nabizada, A. ED - Dechany, A. ED - Carré, B. ED - Ghogare, D. ED - Stendardo, E. ED - Lappa, F. ED - Vanlaere, J. ED - Mendoza, M. J. ED - Dejonghe, M. ED - Daese, M. ED - Namazifard, N. ED - Jacops, R. ED - Jottrand, S. ED - Pahlavan, S. T1 - Modelling of the Manufacturing Process Related Residual Stresses in Type 4 Pressure Vessels for Hydrogen Storage N2 - The publication is an extended abstract on the modelling of the manufacturing process related residual stresses in type 4 pressure vessels for hydrogen storage. A 2D analytical model based on the classical laminate theory and a 3D finite element model are introduced. The calculated residual stress state after the filament winding process as well as the stress state in service are presented and discussed. T2 - European PhD Hydrogen Conference 2024 (EPHyC2024) CY - Ghent, Belgium DA - 20.03.2024 KW - Composite KW - Hydrogen KW - Pressure vessel KW - Residual stresses KW - Filament winding KW - Carbon fiber PY - 2024 VL - 2024 SP - 445 EP - 450 PB - Hydrogen Europe Research, BE-HyFE AN - OPUS4-59779 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Popiela, Bartosz T1 - Einfluss der fertigungsbedingten Eigenspannungen auf die Sicherheit von Typ 4-Druckbehältern N2 - Vorstellung der Erkenntnisse aus einer experimentellen Studie mit langsamen Berstprüfungen an Typ 4-Druckbehältern bei einer Arbeitskreis-Sitzung "Wasserstoff-Drucktanks" der AVK. T2 - AVK-Arbeitskreis-Sitzung "Wasserstoff-Drucktanks" CY - Frankfurt am Main, Germany DA - 26.09.2024 KW - Wasserstoff KW - Druckbehälter KW - Eigenspannungen KW - Langsame Berstprüfung PY - 2024 AN - OPUS4-61134 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Popiela, Bartosz A1 - Schukar, Marcus A1 - Breithaupt, Mathias A1 - Günzel, Stephan A1 - Mair, Georg W. A1 - Krebber, Katerina A1 - Seidlitz, Holger T1 - Embedding of Fiber Optic Sensors Under Industrial Conditions and Distributed Strain Sensing in Type 4 Composite Pressure Vessels N2 - The number of in-operation composite pressure vessels is increasing, partly due to their attractiveness for on-board compressed gas storage and transport applications. A possible way to maintain the highest safety levels is through the structural health monitoring of the composite cylinders. Here, the use of fiber optic sensors appears to be a promising approach. However, the integration of the optical fibers into the composite structure of a pressure vessel has been shown to be challenging. In this study, insights on the embedding of optical fibers in the composite structure under industrial conditions are provided. A protection concept for the ingress and egress of the optical fibers is presented. Finally, the results from destructive slow burst tests are evaluated, showing no clear trend in the impact of the embedded optical fibers on the performance of composite pressure vessels. T2 - 24th International Conference on Composite Materials CY - Baltimore, Maryland, USA DA - 04.08.2025 KW - Composite KW - Pressure vessel KW - Filament winding KW - Fiber optic sensors PY - 2025 SP - 3710 EP - 3717 AN - OPUS4-63886 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Popiela, Bartosz T1 - Embedding of Fiber Optic Sensors Under Industrial Conditions and Distributed Strain Sensing in Type 4 Composite Pressure Vessels N2 - A presentation on the embedding of fiber optic sensors into the composite structure of type 4 composite pressure vessels. Also, the impact of the embedded fiber optic sensors on the burst pressures of type 4 composite pressure vessels was discussed. The presentation was held at ICCM24 in Baltimore, Maryland. T2 - 24th International Conference on Composite Materials CY - Baltimore, Maryland, USA DA - 04.08.2025 KW - Composite KW - Pressure vessel KW - Filament winding KW - Fiber optic sensors PY - 2025 AN - OPUS4-63885 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Popiela, Bartosz T1 - Project summary: Impact of manufacturing process related residual stresses in wound composite material on the operational safety of hydrogen pressure vessels N2 - This presentation is a summary of a doctoral project within the BTU-BAM Graduate School 'Trustworthy Hydrogen'. The results of both theoretical and experimental investigations are presented and discussed. T2 - Summer School 2025 - BTU-BAM Graduate School "Trustworthy Hydrogen" CY - Berlin, Germany DA - 05.07.2025 KW - Composite KW - Pressure vessel KW - Residual stresses KW - Burst test KW - Filament winding KW - Carbon fiber PY - 2025 AN - OPUS4-63067 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Popiela, Bartosz T1 - Better with age? Discussion of creep phenomena during initial loading of type 4 composite pressure vessels N2 - A presentation on the impact of creep phenomena during initial loading on the safety of type 4 composite pressure vessels. A statistical evaluation of slow burst tests shows an increase of the survival rate of initially loaded composite pressure vessels (sustained load and increased pressure) compared to the ones tested in a brand-new state. T2 - ASME Pressure Vessels & Piping Conference (ASME PVP 2025) CY - Quebec, Canada DA - 20.07.2025 KW - Composite KW - Pressure vessel KW - Safety PY - 2025 AN - OPUS4-63760 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Popiela, Bartosz T1 - Better with age? Discussion of creep phenomena during initial loading of type 4 composite pressure vessels N2 - To maintain the highest safety standards for compressed gas storage in composite pressure vessels, a deeper understanding of their ageing mechanism is required. In the present study, the impact of an initial loading under increased temperature and sustained pressure on the safety of type 4 composite pressure vessels is investigated. Two designs of type 4 cylinders were manufactured, the only difference being the internal pressure function used during the filament winding process. Hence, their residual stress state and the quality of the composite layers varied. Ten pressure vessels were initially loaded under sustained pressure and increased temperature, and later subjected to slow burst tests. Comparing the results with cylinders tested in a pristine state underlines a significant improvement in the performance of initially loaded cylinders of one of the designs. This phenomenon was caused by a significant decrease of the scattering of burst pressures within a sample. At the same time, a slight decrease of the burst pressures could be observed. An explanation of this behavior could be supported by strain measurements with fiber optic sensors, which were embedded in the composite material. The strains measured during the initial loading indicate a stress redistribution, which has an impact on the strength of the pressure vessel. Moreover, an increased stiffness during the slow burst tests after initial loading was observed that indicates a better exploitation of the individual layers of the composite structure. The study supports previous observations on the increased performance after initial loading and provides new insights into the strain development in creep effects in type 4 pressure vessels. T2 - AZL Aachen Composite Pipes & Vessels Workgroup Meeting CY - Aachen, Germany DA - 11.11.2025 KW - Composite KW - Pressure vessel KW - Filament winding KW - Creep PY - 2025 AN - OPUS4-64667 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Popiela, Bartosz T1 - Better with age? Discussion of creep phenomena during initial loading of type 4 composite pressure vessels N2 - A presentation on the impact of creep phenomena during initial loading on the safety of type 4 composite pressure vessels. A statistical evaluation of slow burst tests shows an increase of the survival rate of initially loaded composite pressure vessels (sustained load and increased pressure) compared to the ones tested in a brand-new state. T2 - H2 Safety - Kolloquium (TestCert) CY - Berlin, Germany DA - 12.11.2025 KW - Composite KW - Pressure vessel KW - Filament winding KW - Burst test KW - Creep PY - 2025 AN - OPUS4-64690 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Popiela, Bartosz A1 - Günzel, Stephan A1 - Oktaviany, Jennifer A1 - Widjaja, Martinus Putra A1 - Mair, Georg W. A1 - Seidlitz, Holger T1 - Influence of Internal Pressure Regulation During Filament Winding on Failure Mechnism in Type 4 Pressure Vessels: A Case Study N2 - Hydrogen storage is a crucial part of the hydrogen value chain, particularly in terms of safety and social acceptance of hydrogen technologies. For on-board and transportation applications, hydrogen is commonly stored as a compressed gas in pressure vessels. Full composite wrapped Type 4 pressure vessels are especially beneficial due to their high weight-saving potential and their capability to withstand high working pressures. To maintain an appropriate safety level, the mechanical behavior of the composite structure has been the subject of investigation in numerous studies. In this study, the failure mechanisms of two designs of Type 4 cylinders are investigated. The two designs differ solely in the manufacturing process parameters, particularly the internal pressure applied during the filament winding process. Variations in internal pressure result in different residual stress states and changes in the quality of the composite structure. The stacking sequence, materials used, and other manufacturing parameters remain unchanged. The cylinders show different failure mechanisms in slow burst tests: one design fails in hoop windings, while the other one fails in helical windings, despite no stress exaggeration in the fiber direction being observed with embedded optical fibers or in numerical simulations. To explain the failure mechanisms, the quality of the cylinders is investigated. The results of X-ray computed tomography and pulse-echo investigation, highlight the complexity of the interactions between manufacturing process parameters, residual stresses, manufacturing quality, and the mechanical behavior of composite pressure vessels. Resin-rich areas in the composite material are identified as a possible cause of the differing failure mechanisms. T2 - 11th International Conference on Hydrogen Safety ICHS 2025 CY - Seoul, South Korea DA - 22.09.2025 KW - Composite KW - Pressure vessel KW - Filament winding KW - Burst test PY - 2025 SP - 1 EP - 12 AN - OPUS4-64452 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - THES A1 - Popiela, Bartosz T1 - Einfluss fertigungsbedingter Eigenspannungen auf die Betriebssicherheit von nassgewickelten Composite-Druckbehältern mit einem nichttragenden Liner N2 - Im Hinblick auf die globale Herausforderung der Energietransformation steigt der Bedarf an Möglichkeiten zur Energiespeicherung. Eine Technologie, die zunehmend in den Fokus rückt, ist die Energiespeicherung mittels komprimiertem Wasserstoffgas. Insbesondere für mobile und Transport-Anwendungen ist eine geringe Masse des Speichers vorteilhaft, weshalb vollumwickelte Composite-Druckbehälter des Typs 4 zum Einsatz kommen. Diese werden überwiegend im Nasswickelverfahren gefertigt, das durch zahlreiche Prozessparameter und physikalische Effekte charakterisiert wird. Die Wahl der Wickelprozessparameter sowie Schwankungen der Materialkennwerte beeinflussen den Eigenspannungszustand in der Composite-Struktur eines Druckbehälters. Somit wirken sie sich auch auf den Spannungszustand im Betrieb aus. Die vorliegende Dissertation beinhaltet Untersuchungen des Einflusses von fertigungsbedingten Eigenspannungen auf die Sicherheit von Composite-Druckbehältern mit nichttragendem Kunststoff-Liner. Ziel ist es, das mechanische Verhalten von Composite-Druckbehältern besser zu verstehen und deren Sicherheitsniveau sowie Konkurrenzfähigkeit weiter zu steigern. Schwerpunkte der Arbeit sind experimentelle Untersuchungen der Eigenspannungsentstehung und -entwicklung sowie deren Einfluss auf die Behälter-Sicherheit. Im Fokus befindet sich die Exploration von Möglichkeiten zur Verbesserung der Zuverlässigkeit der Behälter durch Variation der Fertigungsparameter und eine Konditionierung nach der Fertigung. Der Eigenspannungszustand wird in numerischen Simulationen sowie mit dem zerstörenden Bohrlochverfahren charakterisiert. Die Überwachung der Spannungsumlagerung während einer Konditionierung unter Zeitstandbelastung erfolgt mit eingebetteten faseroptischen Sensoren, die später zur Dehnungsmessung in zerstörenden, langsamen Berstprüfungen eingesetzt werden. Zur Vertiefung des Verständnisses des Versagensverhaltens der verwendeten 6,8 l-Druckbehälter wird die Finite-Elemente-Methode eingesetzt. Darüber hinaus werden Qualitätsuntersuchungen der Composite-Struktur mittels Mikro-Computertomographie und Impuls-Echo-Verfahren beschrieben. Die Ergebnisse der Untersuchungen zeigen, dass eine Steigerung der Zuverlässigkeit durch eine gezielte Innendruckbeanspruchung der gewickelten Behälter nahezu kostenneutral möglich ist. Dies wird im Rahmen der Arbeit anhand eines Baumusters demonstriert. Darüber hinaus wird die Verbesserung der Zuverlässigkeit der Behälter im Rahmen einer Konditionierung unter Zeitstandbelastung vertieft diskutiert. Diese stellt eine weiterführende Möglichkeit dar, das Behälterverhalten positiv zu beeinflussen und das Sicherheitsniveau zu steigern. N2 - Considering the global challenge of energy transformation, the demand for energy storage solutions is increasing. One of the technologies, which is gaining attention, is the storage of hydrogen gas under high operating pressures. Particularly for on-board and transport applications, lightweight storage systems are advantageous. Therefore, fully wrapped composite pressure vessels of Type 4 are increasingly used. These are mostly manufactured using the wet filament winding process, which is characterized by numerous process parameters and physical effects. The choice of winding process parameters and variations in material properties influence the residual stress state in the finished component and thus also the stress state under operational loads. This dissertation includes insights into the impact of manufacturing-induced residual stresses on the safety of Type 4 pressure vessels, which contribute to a deeper understanding of the mechanical behavior of composite pressure vessels and support the further enhancement of safety levels and competitiveness. The work focuses on experimental investigations of the induction and development of residual stresses and their impact on the safety of the composite pressure vessels. A core of the dissertation is an exploration of the possibilities to improve pressure vessel performance through variation of manufacturing parameters and conditioning after manufacturing. The residual stress state is characterized in numerical simulations as well as with the destructive hole-drilling method. Embedded fiber optic sensors are used for the monitoring of stress redistribution during conditioning. The fiber optic sensors are later used for strain measurement in destructive, slow burst tests. Finite element analyses are performed to deepen the understanding of the failure behavior of the used 6.8-liter pressure vessels. Additionally, quality investigations of the composite structure using micro-computed tomography and impulse-echo ultrasonic propagation imaging are described. The results of the investigations show that an increase in performance is possible through targeted internal pressure regulation during the winding process pressure vessels. This is demonstrated almost cost-neutrally, i.e., without increasing process time and material usage. Furthermore, the improvement of vessel performance through conditioning under increased pressure and temperature is discussed in depth. This represents a further possibility to favorably influence vessel behavior and enhance safety levels. KW - Composite KW - Druckbehälter KW - Eigenspannung KW - Faserverstärkter Kunststoff KW - Nasswickelverfahren PY - 2026 UR - https://nbn-resolving.org/urn:nbn:de:kobv:co1-opus4-72383 DO - https://doi.org/10.26127/BTUOpen-7238 SP - 1 EP - 153 CY - Cottbus, Deutschland AN - OPUS4-65348 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Popiela, Bartosz T1 - Einfluss ausgewählter Fertigungsparameter auf die Sicherheit von Composite-Druckbehältern N2 - In dem Vortrag wurde der Einfluss ausgewählter Fertigungsparameter auf die Sicherheit von Composite-Druckbehältern diskutiert. Die Inhalte stammen aus einem Projekt im Rahmen des BTU-BAM Graduiertenkollegs "Trustworthy Hydrogen". Darüber hinaus umfasst der Foliensatz eine Kurzvorstellung der Aktivitäten des Fachbereichs 3.5 im Bereich der Wasserstofftechnologien. T2 - Workshop "Wasserstoff in der Luftfahrt: Wasserstoffspeicherung und -transport für Luftfahrt und darüber hinaus" CY - Berlin, Germany DA - 11.02.2026 KW - Composite KW - Druckbehälter KW - Fertigung PY - 2026 AN - OPUS4-65498 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kästle, Emanuel D. A1 - Duffner, Eric A1 - Popiela, Bartosz A1 - Ghaznavi, Ali T1 - Monitoring Failure of Composite Pressure Vessels with Acoustic Emissions N2 - Two carbon fiber reinforced type IV pressure vessels are subjected to step-wise pressurization until burst, while monitored using acoustic emissions (AE). Unlike most prior studies, AE data is collected throughout the entire damage progression. The vessels, manufactured with differing parameters, failed in distinct composite layers – A-type in the hoop layers and B-type in the helical layers. The AE signals are evaluated to study material degradation and identify fiber breaks as signs of critical damage accumulation. The signals are distributed randomly across the surface, with localized accumulation only minutes before rupture, close to the rupture plane. The difference in manufacturing parameters did not result in any clear difference in the AE activity. Felicity and Shelby ratios show consistent decline with increasing pressure, suggesting potential for damage assessment and burst prediction. It is discussed how these ratios are affected by coupling quality of the AE sensors, the shape of the pressurization profile and prior loadings. Different signal features based on the amplitude and the frequency content are extracted for a classification into failure mechanisms. Based on previous studies, AE signals corresponding to fiber breaks have a characteristic high-frequency spectrum and show a delay in occurrence, with an increase in the number of breaking fibers towards the end of the experiment. Indeed, high frequency signals tend to occur later and signals in specific peak-frequency ranges (350 – 400 kHz,  500 kHz) somewhat resemble the expected behavior. However, the dataset is too variable and too incongruent for any clear interpretations. Likely reasons are signal propagation effects, the complex composite structure, simultaneous occurrence of signals and measurement uncertainties. A review of relevant studies is provided to show that similar issues affect also previous works. Successfully identifying fiber breaks in large-scale, complex composite structures based on AE data, and turning this into an applicable health-monitoring technique, therefore remains a challenge. KW - Acoustic emission testing KW - Composite pressure vessels KW - Damage classification in fiber reinforced polymers KW - Felicity ratio KW - Composite failure PY - 2026 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-654852 DO - https://doi.org/10.1007/s10921-025-01319-1 SN - 0195-9298 VL - 45 IS - 1 SP - 1 EP - 19 PB - Springer Science and Business Media LLC AN - OPUS4-65485 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Ghafafian, Carineh A1 - Popiela, Bartosz A1 - Nielow, Dustin A1 - Trappe, Volker T1 - Restoration of structural integrity – a comparison of various repair concepts for wind turbine rotor blade shells N2 - Localized patches are a cost- and time-effective method for repairing fiber-reinforced polymer (FRP) sandwich wind turbine rotor blade shells. To increase the understanding of their effect on the fatigue of the blades, this study examines the effect of various layup methods of localized repair patches on the structural integrity of composite sandwich structures. Manufactured with the vacuum-assisted resin infusion (VARI) process, the shell test specimens are produced as a curved structure with glass fiber reinforced polymer (GFRP) sandwiching a polyvinyl chloride (PVC) foam core. Patch repairs are then introduced with varying layup techniques, and material properties are examined with cyclic fatigue tests. The transition region between patch and parent material is studied in greater detail with finite element method (FEM) simulations, with a focus on the effect of fiber orientation mismatch. Damage onset, crack development, and eventual failure are monitored with in-situ non-destructive testing methods to develop a robust understanding of the effects of repair concepts on material stiffness and strength. T2 - SMAR 2019 - 5th International Conference on Smart Monitoring, Assessment and Rehabilitation of Civil Structures CY - Potsdam, Germany DA - 27.08.2019 KW - Lightweight materials KW - Glass fiber reinforced polymers KW - Sandwich KW - Wind turbine blades PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-482170 SP - 1 EP - 8 PB - German Society for Non-Destructive Testing (DGZfP e.V.) AN - OPUS4-48217 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Popiela, Bartosz A1 - Günzel, Stephan A1 - Sklorz, Christian A1 - Widjaja, Martinus Putra A1 - Mair, Georg W. A1 - Seidlitz, Holger T1 - Application of the incremental hole-drilling method for residual stress determination in type 4 pressure vessels N2 - Hole-drilling method is a standardized technique for obtaining residual stresses in isotropic structures. Previous studies provide a foundation that enables the use of this method to investigate orthotropic structures, such as fiber-reinforced composites. In this study, the incremental hole-drilling method was applied to investigate residual stresses in filament wound type 4 composite pressure vessels. The investigated composite cylinders were manufactured with different internal pressure functions during the winding process, to achieve distinct residual stress states. Additionally, the influence of the initial loading under sustained internal pressure and increased temperature on the stress distribution was investigated. It was shown that the residual stress state can be influenced by varying the internal pressure in the winding process. After testing at sustained load and increased temperature, a stress redistribution was observed, which took place due to creep phenomena. Finally, a discussion of the challenges for the application of the hole-drilling method to composite pressure vessels is provided. KW - Hole-drilling method KW - Filament winding KW - Type 4 composite pressure vessels KW - Residual stresses KW - Stress redistribution PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-627765 DO - https://doi.org/10.1515/mt-2024-0328 SN - 2195-8572 VL - 67 IS - 4 SP - 663 EP - 674 PB - Walter de Gruyter GmbH AN - OPUS4-62776 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Popiela, Bartosz A1 - Günzel, Stephan A1 - Mair, Georg W. T1 - Discussion of creep phenomena during initial loading of type 4 composite pressure vessels N2 - To maintain the highest safety standards for compressed gas storage in composite pressure vessels, a deeper understanding of their ageing mechanism is required. In this study, two designs of type 4 cylinders were manufactured the only difference being the internal pressure function used during the filament winding process. Hence, their residual stress state and the quality of the composite layers varied. Ten pressure vessels were initially loaded under sustained pressure and increased temperature and later subjected to slow burst tests. Comparing the results with cylinders tested in a pristine state underlines a significant improvement in the performance of initially loaded cylinders of one of the designs. This phenomenon was caused by a significant decrease of the scattering of burst pressures within a sample. At the same time, a slight decrease of the burst pressures could be observed. An explanation of this behavior could be supported by strain measurements with fiber optic sensors, which were embedded in the composite material. The strains measured during the initial loading indicate a stress redistribution, which has an impact on the strength of the pressure vessel. Moreover, an increased stiffness during the slow burst tests after initial loading was observed that indicates a better exploitation of the individual layers of the composite structure. The study supports previous observations on the increased performance after initial loading and provides new insights into the strain development in creep effects in type 4 pressure vessels. T2 - Pressure Vessels & Piping Conference PVP2025 CY - Montreal, Quebec, Canada DA - 20.07.2025 KW - Type 4 pressure vessel KW - Creep KW - Fiber optic sensors KW - Slow burst test KW - Mechanics of composites PY - 2025 SN - 978-0-7918-8907-7 VL - 2025 SP - 1 EP - 7 PB - ASME AN - OPUS4-63897 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -