High-pressure Hydrogen Vessels Research Articles

Study of composite polymer degradation for high pressure hydrogen vessel by machine learning approach

AbstractThe aim of this article is to study the degradation of a composite material under static pressure. The high pressure condition is similar to the one encountered inside hydrogen tanks. Damage modeling was used to evaluate the behavior of hydrogen tanks to high pressure. A practical approach, coupling a finite element method (FEM) simulation and machine learning (ML) algorithm, is suggested. The representative volume element (RVE) was used in association with a choice of a behavior law and a damage law as an input data. Algorithms for ML classification such as K‐nearest neighbors (k‐NN) and a special k‐NN with a dynamic time warping metric were used. The hierarchical clustering through dendrograms visualizations allowed to exhibit the impact of composite parameters in relation to fiber, matrix properties and fiber volume fraction on the strain degradation under external static pressure. Continuing this, the optimum RVE which shows a low degradation value will be exhibited.

Damage-tolerance design method for composite high-pressure hydrogen vessels of fuel cell vehicles and stacking-sequence optimization method based on the design method

An approach was proposed to design high-pressure composite hydrogen vessels for fuel cell vehicles with damage tolerance. In addition, a stacking-sequence optimization method was developed, which was built upon the damage tolerance design. A no-growth approach, damage categorization, and residual strength requirements were proposed for the damage-tolerance design method for high-pressure hydrogen vessels, which were implemented in the damage-tolerance design method for composite aircrafts. The initial burst pressure was set at 180% of normal working pressure (NWP) assuming that the structural health monitoring (SHM) system with acoustic emission (AE) testing would immediately detect the occurrence of fiber failure. Stacking-sequence optimization was then conducted to minimize vessel thickness and meet the residual strength requirements. As a result of the optimization, the calculations confirmed that the vessel thickness could be reduced by approximately 52% of the existing vessel stacking sequence. The results show that the thickness of the vessel can be reduced by introducing a damage-tolerant design. Moreover, the proposed method for an optimal design based on the damage-tolerance design method is effective.

Analysis of Forming Factors for Build-Up Phenomenon in High Pressure Hydrogen Vessel

Analysis of Forming Factors for Build-Up Phenomenon in High Pressure Hydrogen Vessel

Modelling the conjugate heat transfer during the fast-filling of high-pressure hydrogen vessels for vehicular transport

Compressed gas in cylinders is currently the preferred solution for storing hydrogen on board vehicles. Fast-filling combined with high storage pressures is required to meet competitive targets of long driving ranges and short refuelling times. Experiments and CFD models have shown that the fast-filling leads to significant rise in temperature within the hydrogen cylinder, which can lead to its structural failure. Thus, controlling the rise in temperature is vital during the refuelling process. This paper describes the implementation of a universal thermodynamic model that determines the gas and structural temperature during the fast-filling of hydrogen cylinders. It includes the computation of conjugate heat transfer from the gas to the cylinder structure. The thermodynamic model requires negligible computational time without compromising accuracy and can used to implement different fast-filling scenarios on a laptop or personal computer. The flexibility and robustness of the model is shown as it is capable of modelling the fast-filling of cylinders while varying different key parameters such as fill time, structural material, cylinder volume, final pressure, filling rate, initial temperatures and pressures.

Optimal design of curing process for manufacturing a high pressure hydrogen vessel (type 4)

Optimal design of curing process for manufacturing a high pressure hydrogen vessel (type 4)

Modelling the Conjugate Heat Transfer During the Fast-Filling of High-Pressure Hydrogen Vessels for Vehicular Transport

Modelling the Conjugate Heat Transfer During the Fast-Filling of High-Pressure Hydrogen Vessels for Vehicular Transport

Damage assessment and mechanical performance of Cr-Mo steel used in hydrogen storage vessels

The proposed study investigates the potential damage in an actual hydrogen vessel and the mechanical performance of Cr-Mo steel used in high-pressure hydrogen vessels. The hydrogen vessel exhibited defects, such as small fissures and various types of inclusions, which may have a detrimental effect on its performance under hydrogen gas. The maximum tensile strength of the steel under high-pressure hydrogen met the design standard requirement (i.e., it did not exceed 915 MPa), and hydrogen had a significant effect on the strain at fracture and reduction in area. The occurrence of intergranular fracture was more pronounced in the specimens exposed to 99 MPa of hydrogen than those exposed to 10 MPa of hydrogen, resulting in a slightly higher embrittlement index.

Evaluation of stress and crack behavior using the extended finite element method in the composite layer of a type III hydrogen storage vessel

To facilitate the widespread use of fuel cell vehicles, it is necessary to ensure the safety of high-pressure hydrogen storage vessels. Because the composite layer experiences the highest internal pressure, cracks in the carbon fiber reinforced plastic (CFRP) layer of type III high-pressure vessels directly affect their safety. In this study, we evaluate the crack behavior in a type III high-pressure hydrogen vessel using a ply modeling method and the extended finite element method. The failure criteria were determined from the maximum principal stress and displacement that exceed the allowable tensile strength, considering the fiber and the transverse directions of each ply. The weak point of the CFRP composite layers was in the transverse direction on the 17th ply at a helical winding angle of 35° in the boundary of the dome and the cylinder. The crack extension was resulted from exceeding the allowable transverse stress at 35° winding angle. These results may be valuable for ensuring the safety of high-pressure hydrogen vessels.

Computational approach for hydrogen leakage with crack propagation of pressure vessel wall using coupled particle and Euler method

New computational approach for hydrogen leakage with wall crack propagation problem was conducted by using a hybrid of the coupled particle and Eulerian methods. This computational method provides useful safety information for predicting crack propagation and hydrogen leakage in pressure vessels as an important part of assessing hydrogen as an energy vector. The present computational analysis procedures consisted of two main parts. The first part was crack propagation analysis of a thin square plate, which simulated the wall of a high-pressure hydrogen vessel by using a particle method. The crack propagation was analyzed in high-pressure tank walls under two different types of initial conditions, and in both cases, the direction of crack propagation was freely determined by the direction of the stress field. This confirms the superiority of particle methods for modeling destructive phenomena. After the crack propagation analysis, the particle location and coordinate data of the barrier wall were converted to Euler mesh data. The geometric data of particle location were fitted to Euler numerical space, which was used for simulating high-pressure hydrogen leakage into air at atmospheric pressure. The differences and features of hydrogen diffusion during hydrogen leakage were analyzed for two types of wall data and two types of boundary conditions, as a result, the effect of wall boundaries on the hydrogen concentration distribution was computationally predicted.

Sheet sensor using SrAl2O4:Eu mechanoluminescent material for visualizing inner crack of high-pressure hydrogen vessel

A new non-destructive evaluation technique to detect cracks emanating from the inner surface (inner cracks) of a high-pressure hydrogen storage cylinder was developed by means of mechanoluminescence (ML) sensor consisting of SrAl2O4:Eu ML material and epoxy resin. To visualize the inner crack, a sheet ML sensor was attached onto the outer surface of the storage cylinder subjected to hydraulic pressure cycling with the maximum pressure of 45 MPa. The ML pattern was changed with an increase in the cycle number and the ML sensor could visualize the inner crack. The stress analysis by the finite element method clarified that the ML sensor provided unique equivalent strain distribution associated with stress concentration at the crack tip, i.e. the distance between two points having high equivalent strains was inversely proportional to the crack depth; consequently, the growth behavior of the inner crack was non-destructively quantified with the ML sensor attached on the outer surface.

GASFLOW simulations of a Bonfire test

The Computational Fluid Dynamic (CFD) code GASFLOW was used to simulate a Bonfire test for studying the safety performance of high-pressure hydrogen vessels for vehicular storage applications. A thermal loading model representing the azimuthal temperature dependency of the internal gas was implemented in the simulation code GASFLOW and is described in details in this paper. The GASFLOW simulations show good agreement with previous simulation results and with data.

Thermal Stress Analysis of Fiber Wrapped High-Pressure Hydrogen Vessel

In order to reveal the influence of thermal on the stress distribution of fiber wrapped high-pressure hydrogen vessel, the strain and stress of the vessel in pure mechanical loads are studied firstly. Then thermal loads are taken into account, and the thermal stress distribution is given out. The results show that, the stress of the vessel liner changes little when the loads differ from pure mechanical loads to thermal mechanical coupling loads. While in the fiber-wrapped layer, stresses change significantly, and are non-monotonic. In addition, the deformation of the vessel decreases under thermal mechanical coupling loads.

Crack Growth Behavior of Sealing Rubber under Static Strain in High-Pressure Hydrogen Gas

In order to enable hydrogen society in the near future, it is necessary to clarify the influence of hydrogen on the mechanical, physical and chemical properties of the materials used for hydrogen energy systems. In the case of rubbers, there is a particular danger of mechanical damage resulting from internal fracture, which occurs when high-pressure hydrogen gas is suddenly decompressed. Although our previous studies focused on fracture and deformation caused by high-pressure hydrogen decompression, the fracture and deformation of rubber materials under pressurization have not been studied. From this viewpoint, static crack growth tests of an unfilled sulfur-crosslinked ethylene-propylene-diene monomer (EPDM) rubber were conducted in hydrogen gas at 10 MPa and room temperature (around 25°C) by using a high-pressure hydrogen vessel with glass viewing ports. Deformation of the rubber during pressurization was hardly seen at ≤ 10 MPa, although hydrostatic pressure was applied and hydrogen gas penetrated into the rubber. The static crack growth rate for hydrogen gas at 10 MPa was consistent with that in air (0.1 MPa). A lot of facets with about 100 µm in size caused by the initiation and successive coalescence of secondary cracks ahead of the main crack were observed on the fracture surface of the specimens tested in air and hydrogen gas at 10 MPa, and these fracture surfaces showed a similar aspect. From these results, it was clarified that a hydrogen environment at ≤ 10 MPa did not influence the static crack growth characteristic of the rubber.

Thermal characteristics during hydrogen fueling process of type IV cylinder

Temperature increase during hydrogen fueling process is a significant safety concern of a high pressure hydrogen vessel. Hence, thermal characteristics of a Type IV cylinder during hydrogen filling process need to be understood. In this study, a series of experiments were conducted to quantify the temperature change of the cylinder during hydrogen filling to 35 MPa. Computational fluid dynamics (CFD) analysis was also conducted to simulate the conditions of the experiments. The results predicted by the CFD analysis show reasonable agreement with the experiments and the discrepancy between the CFD results and experimental results decrease with higher initial gas pressures. The upper and the lower parts of the vessel showed a temperature difference in the vertical direction. The upper gas temperature was higher than that of the lower part due to the buoyancy effect in the vessel. The maximum gas temperature was higher than the maximum temperature allowed in the ISO safety code (85 °C) for the case in which the vessel was pressurized from 0 MPa to 35 MPa. This work contributes to the understanding of the thermal flow characteristics of the hydrogen filling process and notes that additional efforts should be made to guarantee the safety of a type IV cylinder during the hydrogen fueling process.

高圧水素ガス圧力容器用ゴム製シール材の損傷解析

高圧水素ガス圧力容器用ゴム製シール材の損傷解析

Technical Basis and Application of New Rules on Fracture Control of High Pressure Hydrogen Vessel in ASME Section VIII, Division 3 Code

As a part of an ongoing activity to develop ASME Code rules for the hydrogen infrastructure, the ASME Boiler and Pressure Vessel Code Committee approved new fracture control rules for Sec. VIII, Division 3 vessels in 2006. These rules have been incorporated into new Article KD-10 in Division 3. The new rules require determining fatigue-crack-growth rate and fracture resistance properties of materials in high pressure hydrogen gas. Test methods have been specified to measure these fracture properties, which are required to be used in establishing the vessel fatigue life. An example has been given to demonstrate the application of these new rules.