Investigation of Variable Axial Reinforcements of Lateral Pressure Vessel Openings using Element Level Pipe Specimens
Topic(s) : Special Sessions
Co-authors :
Michael BIRKE (GERMANY), Jonas RICHTER (GERMANY), Friedrich TOEPFER (GERMANY), Sebastian SPITZER (GERMANY), Maik GUDE (GERMANY)Abstract :
Hydrogen offers a viable way to reduce reliance on fossil fuels in aviation. In particular, the use of high-pressure hydrogen is being investigated for short-haul and small aircraft applications. A key challenge is to increase the gravimetric and volumetric storage density. Carbon fibre reinforced polymers (CFRP) have generally become the standard in this area. However, such storage systems require considerable space. Therefore, the strategic placement of 'aerodynamic' tanks under the wings rather than in the fuselage may prove advantageous. However, the pressure ports are currently connected to the pylon caps, which results in disadvantages for the connection to the wing in the centre of the tank in terms of hydrogen line length and the associated additional mass and installation space. Outside of these specific aeronautic applications, there is also a high demand for lateral openings in pipelines and pressure vessels, particularly in the low-pressure range.
This research demonstrates the potential of using localised, variable axial Tailored Fiber Placement (TFP) reinforcements to mitigate stress concentrations around new lateral openings. The study introduces a virtual-physical design process to develop a methodology for the conception and design of these structural reinforcements. Starting with the design of a suitable laminate structure for high pressure tanks, a representative layer sequence is derived for tube specimens corresponding to the element level. Verification of the developed finite element (FE) models and the design approach is carried out by pressure testing on actual tubes under pressure vessel loading conditions using water. This approach integrates advanced materials engineering concepts with practical testing and represents a comprehensive strategy for improving the structural integrity of high pressure systems.
The authors present numerical investigations as a basis for deriving variable-axial design patterns. Depending on the distribution of principal stresses, the proposed method generates proposals for manufacturable reinforcement layers with locally adapted fibre orientations. These proposals are then verified physically or virtually using appropriate methods. Benchmark analyses, such as comparisons with local thickening or literature proposals, are performed to contextualise the potential of the TFP reinforcements presented in this study. This comprehensive approach integrates stress distribution analysis with practical design considerations, providing a refined methodology for tailoring reinforcement layers in high-stress environments.
This research demonstrates the potential of using localised, variable axial Tailored Fiber Placement (TFP) reinforcements to mitigate stress concentrations around new lateral openings. The study introduces a virtual-physical design process to develop a methodology for the conception and design of these structural reinforcements. Starting with the design of a suitable laminate structure for high pressure tanks, a representative layer sequence is derived for tube specimens corresponding to the element level. Verification of the developed finite element (FE) models and the design approach is carried out by pressure testing on actual tubes under pressure vessel loading conditions using water. This approach integrates advanced materials engineering concepts with practical testing and represents a comprehensive strategy for improving the structural integrity of high pressure systems.
The authors present numerical investigations as a basis for deriving variable-axial design patterns. Depending on the distribution of principal stresses, the proposed method generates proposals for manufacturable reinforcement layers with locally adapted fibre orientations. These proposals are then verified physically or virtually using appropriate methods. Benchmark analyses, such as comparisons with local thickening or literature proposals, are performed to contextualise the potential of the TFP reinforcements presented in this study. This comprehensive approach integrates stress distribution analysis with practical design considerations, providing a refined methodology for tailoring reinforcement layers in high-stress environments.