TY - CONF A1 - Schulz, Michael A1 - Gregor, Christian T1 - Assessment of state of residual stress of hybrid pressure vessels N2 - For fully carbon fibre wrapped pressure vessels with load sharing metallic liner (Type III), it was recognized that the state of residual stress given after the autofrettage process can change even if the vessel is stored without pressure. This change is influenced by temperature and time and has a direct effect on the residual lifetime of the vessel. To study the influence of the temperature on the state of residual stress an analytical model was applied which is based on the Classical Laminate Theory (CLT). According to the model, the critical conditions leading to a decrease in lifetime were identified. To confirm the results of the model temperature cycle tests were carried out. The results of the tests are compared with the analytical model and a finite element model. To investigate the influence of time on the state of residual stress, tests on vessels were performed. The tested vessels were aged without any pressure for a longer period of time after the autofrettage process. During these tests, the strain of the vessels was monitored. T2 - ASME 2009 Pressure vessels and piping conference CY - Prague, Czech Republic DA - 2009-07-26 KW - Pressure vessel KW - Residual stress KW - Composite material PY - 2009 SP - PVP2009-77993, 1-9 PB - American Society of Mechanical Engineers CY - New York AN - OPUS4-20052 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schulz, Michael T1 - Einfluss von Imperfektionen auf die mechanischen Eigenschaften von Compsitewerkstoffen am Beispiel von Druckbehältern T2 - CNG/H2-Round Table, Expertenkreis "Speichertechnik", BAM CY - Berlin, Germany DA - 2008-11-20 PY - 2008 AN - OPUS4-18457 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schulz, Michael T1 - On the creep rupture prediction of composite pressure vessels T2 - ASME 2010 Presssure Vessels & Piping Conference CY - Bellevue, WA, USA DA - 2010-07-18 PY - 2010 AN - OPUS4-21840 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schulz, Michael T1 - On the creep rupture prediction of composite pressure vessels N2 - This article illustrates a concept of predicting the time dependent deformation and creep rupture strength of carbon fibre reinforced plastics (CFRP). In the presented concept the viscoelastic behaviour of the resin is determined by creep rupture tests at different temperature and load levels. Out of the experiments the relaxation spectrum of the resin is modelled including the spread. With the help of the classical rule of mixture and a modified classical laminate theory the minimum strain rate for the composite will be determined. The results will be compared to experimental data. Furthermore the Monkman-Grant approach is used to determine the time-to-failure strain-rate relation. Therefore an elastic solution of the classical laminate theory is used including Puck´s failure criteria to compute the Monkman-Grant relation. A Monte Carlo Simulation will be done to include the spread of the Monkman-Grant relation. The results will be compared to experimental results of unidirectional specimens. Finally it will be explained how the lifetime of a pressure vessel can be computed using the explained concept. T2 - ASME 2010 Pressure vessels & piping conference CY - Bellevue, Washington, USA DA - 2010-07-18 PY - 2010 IS - PVP2010-26034 SP - 1 EP - 11 PB - American Society of Mechanical Engineers CY - New York AN - OPUS4-22725 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schulz, Michael A1 - Gregor, Christian T1 - Assessment of State of Residual Stress of Hybrid Pressure Vessels T2 - ASME PVP 09 Students Competitions CY - Prague, Czech Republic DA - 2009-07-31 PY - 2009 AN - OPUS4-20025 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schulz, Michael A1 - Mair, Georg T1 - Forschungsaktivitäten an Leichtbaubehältern aus faserverstärkten Kunststoffen für den Gefahrgutbereich T2 - Transport Logistic 2011 CY - Munich, Germany DA - 2011-05-10 PY - 2011 AN - OPUS4-23798 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schulz, Michael A1 - Mair, Georg T1 - FUNDAMENTAL EXAMINATION OF A NEW CONCEPT OF SAFETY SURVEILLANCE AND INTERACTIVE DETERMINATION OF SAFE SERVICE LIFE FOR COMPOSITE PRESSURE VESSELS BY DESTRUCTIVE TESTS PARALLEL TO OPERATION T2 - !&TH iNTERNATIONAL cONFERENCE ON cOMPOSITE sTRCTURES 8iccs!&9 CY - Oporto, Portugal DA - 2011-06-28 PY - 2011 AN - OPUS4-23997 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hoffmann, Martin A1 - Gregor, Christian A1 - Schulz, Michael A1 - Szczepaniak, Mariusz A1 - Mair, Georg T1 - Entwickelt und validiert - Probengeometrie zur Untersuchung von gewickelten Faserverbundproben N2 - Durch die beschriebene, auf eine Umfangsbelastung ausgelegte Probengeometrie werden Fertigung und Einsatz von Druckbehältern nachempfunden. Dafür wurden bereits bestehende Probenformen überarbeitet, um im Probenkörper eine unidirektionale Zugbelastung zu erzeugen. Da die endgültigen Eigenschaften von faserverstärktem Kunststoff erst in der Fertigung entstehen, sind gleiche Fertigungsbedingungen von Proben und Bauteilen wichtig. Die hier vorgestellte Probe verspricht dadurch eine gute Eignung für den Einsatz bei Untersuchungen zum Zeitstandsverhalten. KW - Faserverstärkte Kunststoffe (FVK) KW - Druckbehälter KW - Zeitstand KW - Zugprobe PY - 2012 SN - 1865-4819 VL - 5 SP - 44 EP - 49 PB - Springer Vieweg, Springer Fachmedien Wiesbaden GmbH CY - Wiesbaden AN - OPUS4-26893 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -