TY - CONF A1 - Casperson, Ralf A1 - Pohl, Rainer A1 - Lohde, Sebastian A1 - Aydoğdu, M. T1 - Non-Destructive Testing of Composite Pressure Vessels using Conventional and High-Frequency Eddy Current Technique N2 - Composite-Druckgefäße für den Gefahrguttransport sowie für Wasserstoff- und Erdgasfahrzeuge bestehen aus einem lasttragenden Composite und einer gasdichten, metallischen oder polymeren Barriereschicht (Liner). Zur Untersuchung des Alterungsverhaltens solcher Composite-Druckgefäße wurde in der BAM das interdisziplinäre Themenfeldprojekt COD-AGE durchgeführt. Ziel des Projektes war die Entwicklung von Methoden und Modellen zur Beschreibung und Bestimmung des Alterungsverhaltens von Carbonfaser-Compositen am Beispiel von Druckgefäßen, um eine bessere Vorhersage der Alterung und der sicheren Gebrauchsdauer zu ermöglichen. Ein Schwerpunkt in diesem Projekt war die Bereitstellung geeigneter ZfP-Methoden. Dabei ging es sowohl um versuchsbegleitende Prüfungen, als auch um die mögliche Entwicklung von Prüfeinrichtungen für den späteren praktischen Gebrauch. In dem Vortrag werden Prüfergebnisse der alterungsbegleitenden Wirbelstromprüfung an Composite-Druckgefäßen vorgestellt. In Alterungsversuchen wurden Druckgefäße aus einem ca. 4 mm dicken Aluminiumliner und ca. 8 mm dicker CFK-Ummantelung untersucht. Typisches Einsatzgebiet solcher Druckgefäße sind Atemschutzgeräte der Feuerwehr. Die Druckgefäße wurden sowohl mit konventioneller Wirbelstromtechnik von außen und von innen als auch mit hochfrequenter Wirbelstromtechnik von außen geprüft. Es konnten sowohl Beschädigungen des metallischen Liners, als auch Strukturen des CFK-Geflechts nachgewiesen werden. Eine besondere mechanische Herausforderung bestand in der Prüfung der Innenseite der Liner, da hier eine zylindrische Fläche mit einem Innendurchmesser von 150 mm durch einen Zugang von nur 15 mm Durchmesser geprüft werden muss. N2 - Composite pressure vessels for transporting dangerous goods and for hydrogen and natural gas vehicles consist of a load-bearing composite and a gas-tight, metallic or polymeric barrier layer (liner). To investigate the aging behavior of such composite pressure vessels, BAM carried out the interdisciplinary project COD-AGE. The aim of the project was the development of methods and models for the description and determination of the aging behavior of carbon fiber composites using the example of pressure vessels in order to better predict aging and safe working life. One focus of this project was the provision of suitable NDT methods. These included both test-related tests and the possible development of test equipment for later practical use. In the lecture, test results of the age-related eddy current test on composite pressure vessels are presented. In aging tests, pressure vessels made of an approximately 4 mm thick aluminum liner and approx. 8 mm thick CFRP layer were examined. Typical application of such pressure vessels are respiratory protective devices of the fire department. The pressure vessels were tested using conventional eddy current technology from the outer and inner side as well as with high-frequency eddy current technology. Both damage to the metallic liner and structures of the CFRP could be detected. A particular mechanical challenge was the inspection of the inside of the liners, since a cylindrical surface with an inside diameter of 150 mm has to be tested with an access of only 15 mm diameter. T2 - TAHYA-Workshop CY - Berlin, Germany DA - 27.11.2019 KW - NDT KW - Composite pressure vessel KW - CFRP KW - Eddy current testing PY - 2019 AN - OPUS4-49829 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - John, Sebastian A1 - Mair, Georg A1 - Schoppa, André A1 - Szczepaniak, Mariusz T1 - Monitoring of residual stresses in composite pressure vessels via modal analysis N2 - Within a current research project at the Federal Institute for Materials Testing and Research (BAM), the degradation process of composite pressure vessels is studied to be able to give more accurate lifetime predictions in future. The presented research is based on type III pressure vessels consisting of an aluminium tank which is fully wrapped with carbon fibre reinforced plastics. Focus is set on the analysis of residual stresses which are induced into the pressure vessel during manufacturing process in order to increase high cycle fatigue. However, with increasing lifetime residual stress conditions do change. To be able to measure and monitor stress conditions, the application of a non-destructive measurement method is aspired. In this paper, potential of an experimental modal analysis is worked out to capture and monitor aging and degradation effects in pressure vessels. With the presented method, information about changes in residual stress can be obtained via an analysis of the modal parameters. To realize an application, first, a finite element simulation is used to prove and evaluate potential capability and validity. In the following, a test bench is set up and successively optimized in its accuracy and efficiency. Sensitivity of the applied measurement technique is experimentally ascertained trough the measurement of several prestress modified pressure vessels. Finally, experimental results are interpreted and evaluated with the help of numerically gained findings. T2 - NOVEM 2018 CY - St. Eulalia, Ibiza, Spain DA - 07.05.2018 KW - Composite pressure vessel KW - Residual stress KW - Modal analysis PY - 2018 VL - 6 SP - Paper 175090, 1 EP - 9 AN - OPUS4-45220 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - John, Sebastian A1 - Mair, Georg A1 - Schoppa, André A1 - Szcepaniak, Marisz T1 - Monitoring of residual stresses in composite pressure vessels via modal analysis N2 - At the Bundesanstalt für Materialforschung und –prüfung (BAM), within a recent research project, the aging process of composite pressure vessels is investigated in order to be able to give more accurate lifetime predictions in future. All investigations are primarily based on type III pressure vessels consisting of an aluminium tank which is fully wrapped with carbon fibre reinforced plastics. Research is focused on residual stresses which are induced into the pressure vessel during manufacturing process in order to increase high cycle fatigue. However, with increasing lifetime residual stress conditions of type III pressure vessels change. For measuring and monitoring inner stress conditions, the application of a non-destructive measurement method is aspired. Within this paper, the potential of an experimental modal analysis is tested to determine aging and degradation effects of pressure vessels. Based on this method, information about changes of the residual stresses can be obtained via an analysis of the modal parameters. Realizing this, first a finite element model is used to prove and evaluate potential capability and validity for the application of an experimental modal analysis. Based on this, a test bench is set up and successively optimized in its accuracy and efficiency. The sensitivity of the applied measurement technique is experimentally evaluated via measuring multiple prestress modified pressure vessels. Furthermore, a selection of prestress modified pressure vessels is monitored via the presented method. Finally, experimentally obtained results are interpreted and evaluated with the help of numerically gained finding. T2 - NOVEM 2018 CY - St. Eulalia, Spain DA - 08.05.2018 KW - Composite pressure vessel KW - Residual stress KW - Cod-age KW - Modal analysis PY - 2018 AN - OPUS4-45242 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - John, Sebastian T1 - Sensitivity analysis of residual stresses in composite pressure vessels via modal analysis N2 - Due to high specific stiffness and strength properties, fibre reinforced plastics are used more and more often for the construction of pressure vessels. Within a recent research project run by the Federal Institute for Materials Research and Testing (BAM), aging process of composite pressure vessels is investigated in order to be able to give more accurate lifetime predictions in the future. Focus is set on type III pressure vessels consisting of an aluminium tank which is fully wrapped with carbon fibre reinforced plastics. In order to increase high-cycle fatigue, residual stresses are induced into the pressure vessel during manufacturing process. In particular, residual compressive stresses within the inner aluminium layer have been defined as a main parameter affecting fatigue strength. The aim is to identify and evaluate residual stresses of the pressure vessel by analysing its modal parameters. Through the set-up of a finite-element model potential capability and validity for the use of modal analysis is proven and evaluated, considering influences resulting from manufacturing deviations, too. In the following, a number of stress sensitive modes are defined. Based on these preliminary numerical investigations, a test bench is set up in order to measure pressure vessels via an experimental modal analysis. A final critical evaluation regarding the accuracy of the modal analysis is made by comparing experimental results with data obtained through simulations. T2 - INTER-NOISE 2017 - 46th International Congress and Exposition on Noise Control Engineering CY - Hong Kong, People's Republic of China DA - 27.08.2017 KW - Composite pressure vessel KW - Modal analysis PY - 2017 AN - OPUS4-41843 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - John, Sebastian A1 - Mair, Georg T1 - Sensitivity analysis of residual stresses in composite pressure vessels via modal analysis N2 - Due to high specific stiffness a nd strength properties, fibre reinforced plastics are used more and more often for the construction of pressure vessels. Within a recent research project run by the Federal Institute for Materials Research and Testing (BAM), aging process of composite pressure vessels is investigated in order to be able to give more accurate lifetime predictions in the future. Focus is set on type III pressure vessels consisting of an aluminium tank which is fully wrapped with carbon fibre reinforced plastics. In order to increase high-cycle fatigue, residual stresses are induced into the pressure vessel during manufacturing process. In particular, residual compressive stresses within the inner aluminium layer have been defined as a main parameter affecting fatigue strength. The aim is to identify and evaluate residual stresses of the pressure vessel by analysing its modal parameters. Through the set-up of a finite-element model potential capability and validity for the use of modal analysis is proven and evaluated, considering influences resulting from manufacturing deviations, too. In the following, a number of stress sensitive modes are defined. Based on these preliminary numerical investigations, a test bench is set up in order to measure pressure vessels via an experimental modal analysis. A final critical evaluation regarding the accuracy of the modal analysis is made by comparing experimental results with data obtained through simulations. T2 - INTER-NOISE 2017 46th International Congress and Exposition on Noise Control Engineering CY - Hong Kong, People's Republic of China DA - 27.08.2017 KW - Composite pressure vessel KW - Modal analysis PY - 2017 SP - 6309 EP - 6316 CY - Hong Kong AN - OPUS4-41842 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -