Session: HT-01-01 Design, Analysis and Life Prediction of High-Pressure Vessels and Equipment

Paper Number: 151391

151391 - Discussion of Creep Phenomena During Initial Loading of Type 4 Composite Pressure Vessels 

Abstract: 

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.

Presenting Author: Bartosz Popiela Bundesanstalt für Materialforschung und -prüfung (BAM)

Presenting Author Biography: Bartosz Popiela studied Mechanical Engineering at the Technical University of Berlin and obtained his Master of Science in 2021. Since 2022 he is a PhD Candidate in the Division 3.5 “Safety of Gas Storage Systems” of the Federal Institute for Materials Research and Testing (BAM) in Berlin, Germany.

Authors:

Bartosz Popiela Bundesanstalt für Materialforschung und -prüfung (BAM)
Stephan Günzel Bundesanstalt für Materialforschung und -prüfung (BAM)
Georg W. Mair Bundesanstalt für Materialforschung und -prüfung (BAM)