Composite Tank Research Articles

Composite pressure vessels for hydrogen storage in fire conditions: Fire tests and burst simulation

A type IV composite pressure vessel subjected to fire may burst because of the degradation of the outer layers, but when the inner pressure is less than a critical value, leak is observed instead of burst. This phenomenon is due to the heat transfer through the composite shell which leads to liner melting. In order to characterize this failure mechanisms, engulfing fire tests have been performed in the framework of the FireComp project whose objective is to understand and simulate the fire performance of hydrogen storage. An experimental set-up has been implemented to expose the cylinders to fire by the means of gas injectors. A simple FE model has been developed to simulate the coupled effects of mechanical damage and of temperature. This approach is found to accurately predict the time to burst of the composite tank, as well as the transition between burst and leak.

About the demisability of propellant tanks during atmospheric re-entry from LEO

The concern about the on-ground risk caused by spacecraft fragments surviving atmospheric re-entry has significantly grown during the past decade, resulting in numerous activities of the space community like re-entry simulation tool development, improvement, and validation, as well as research for design-for-demise (D4D). The purpose of the first group is to increase the confidence in numerical re-entry risk predictions, while the second activity aims to develop new spacecraft design techniques which are likely to improve the demise behavior significantly.Standard (Titanium) propellant tanks for LEO (Low Earth Orbit) missions appear regularly within the group of spacecraft (satellite) components causing the highest on-ground risk, i.e. in the order of 20% for a 1-ton class Earth observation satellite. Thus, tanks are one of the primary targets for any D4D activity. Various ideas for demisable propellant tank concepts have been published recently, including aluminum tanks (e.g. based on aluminum-lithium alloys) or composite tanks (e.g. Carbon-fiber overwrapped metallic liners).The demonstration of the actual demisability of such new tank concepts has turned out to be difficult, sometimes even questionable. Intensive laboratory tests in arc-jet heated or plasma wind-tunnels and laser facilities have provided extensive results. Numerical simulations have been conducted to reproduce these experimental findings.This paper will contain a critical review of the latest experimental and numerical results about the demisability of satellite propellant tanks during atmospheric re-entry from LEO.

Analysis and testing of polymer matrix composites with thermoplastic liners having enhanced chemical resistance

Polymer matrix composite tanks offer major advantages to the transport industry in terms of increased payload and corrosion resistance compared to conventional steel tanks. Chemical resistance and versatility can be enhanced through the addition of a thermoplastic liner. This paper presents the results of chemical conditioning, testing and analysis of a linear low-density polyethylene liner, on its own and supported by carbon fiber reinforced polymer. Results are compared to ADR (European Agreement Concerning the International Carriage of Dangerous Goods by Road) requirements. The linear low-density polyethylene liner was tested in combination with 12–15% sodium hypochlorite and 98% sulphuric acid. The results indicate that the liner is suitable for service in tanks transporting these two chemicals. Liners were conditioned at 50℃ for periods of 1000 or 2000 h. Shore D hardness tests and three-point bend tests were performed, compared to unconditioned benchmarks, and found to pass ADR requirements. Finite element models were validated and used to facilitate understanding of the failure of the laminates. Predictions indicate that failure load increases with increased liner modulus, yield stress, and thickness. The models also indicate that the laminate strength and modulus is not significantly changed during chemical conditioning for the stated chemicals.

The Electrostatic Safety Assessment Methods for Integrated Composite Fuel Tank Based on the Airworthiness Verification

Integral composite fuel tank refers to that the main key parts or the all force components are made of composite and participate in the whole force acting on the wing. Fully comprehensive utilization of the wing structure can be made by the use of integral fuel tank structure. And the weight could be reduced drastically by the use of composite. Although the composite material has so many advantages, it has a lower conductivity compared with metal which can easily cause the accumulation of electrostatic charges and may lead to fire or explosion as a result of that. So, the design and assessment of electrostatic safety of the integral composite fuel tank seem to be a so important task that even the airworthiness regulations have made requests. In this paper, the background of the fuel tank electrostatic safety had been illustrated, and the necessity of the assessment of such kind of tank had been demonstrated. At last, the test items and assessment ways had been discussed.

Simplified model of a dual-media molten-salt thermocline tank with a multiple layer wall

Thermal ratcheting is a critical phenomenon associated with the cyclic operation of dual-media thermocline tanks in solar energy applications. To study this phenomenon, it is necessary to develop a comprehensive model of a thermocline tank that includes both the heterogeneous filler region and the composite tank wall. Because CFD models require a high computational cost to simulate a thermocline tank considering transient state operation, a simplified dual-phase model that includes the unsteady heat transfer through a multiple layer wall has been developed. The filler region consists of a rock bed with interstitial molten salt, and the tank wall is composed of a steel shell with two layers of insulation (firebrick and ceramic). In this simplified model, the fluid flow inside the tank is considered to be one-dimensional along the tank axis direction, whereas the heat conduction in the composite wall is considered to be two-dimensional. Therefore, a convective heat transfer coefficient from the bed to the wall is necessary to couple the molten salt flow with the heat transfer in the tank shell. In this work, the effects of both convective heat transfer from the bed to the wall and molten salt flow rate on the time-dependent thermal response of both the steel shell and molten salt have been analyzed. The simplified model is able to predict the temperatures of the molten salt, filler material and layer wall as well as the mechanical stress in the tank shell.

The Use of Phytase and Acidifier Supplementation on Growth and Feed Utilization of Tra Catfish (Pangasianodon Hypophthalmus)

In the study five iso-nitrogenous and iso-energetic diets were formulated. T1 was a control with DCP (di-calcium phosphate) supplementation, T2 without DCP, T3 was a T2 supplemented with Acidifier (0.3% formic acid), T4 was a T2 supplemented with phytase (750 FTU/kg) and T5 was a T2 supplemented with Acidifier and phytase. Tra catfish fingerlings (15g) were cultured in 500 liter composite tanks in 10 weeks. The study indicates dietary supplementation of phytase (T4 and T5) significantly improved growth performances, ameliorated feed utilization and increased ash content of the whole body and bone phosphorus of juvenile Tra catfish. The study also indicates supplementing acidifier also improved growth performance, ameliorated feed utilization and increased ash content of the whole body and bone phosphorus. The decreased pH value of gastric juice due to the acidifier supplementation can accounts for the present result. However, mixture of phytase and an acidifier in T5 treatment does not have any ameliorated effect when compared to the separated phytase or separated acidifier. It seems the synergic effect of a mixture does not exist in the study. Some studies are needed to find out the suitable mixture of the two feed additives in Tra catfish feed.

粘土を主成分とする膜の開発と複合材製タンクガスバリア層への応用

粘土を主成分とする膜の開発と複合材製タンクガスバリア層への応用

Innovative automated factory starts to produce composite CNG solutions for one of the most-progressive auto-brands: Automated Filament Winding Production Cell will produce competitive composite CNG tanks

World known composite machine manufacturer, Mikrosam, deliver a fully automated Filament Winding Line for Type IV premium quality CNG vessels. Developed for a leading global automotive supplier Magna, and installed at its plant in Austria, this production cell was designed to manufacture a cost-effective lightweight CNG tank module. Using filament winding technology and application of composite materials, the produced alternative propulsion system would result in reduction of weight of up to 50% compared to equivalent steel cylinders and 40% lower fuel expenses. The CNG vehicle is environment-friendly. This kind of powertrain system will shrink the CO2 emission by 20% to 29%. The CNG module of tanks is predicted to hold a total of 19 kg of gas, allowing the range of over 500 kilometers.

Behaviour of composite conical tanks under hydrostatic pressure

Conical vessels are used around the globe for liquid storage in water tanks. These vessels can be made of steel, reinforced concrete, or composite; i.e. concrete and steel. Composite vessels consist of an external steel shell attached to an internal reinforced concrete wall through steel studs. Previous studies available in the literature focused on studying steel or reinforced concrete vessels. To the best of the author’s knowledge, this paper presents the first comprehensive study conducted on liquid-filled composite tanks. A Finite Element Model for Composite tanks (CFEM), which accounts for both the geometric and material nonlinearities, is developed. The material nonlinearity is considered by including nonlinear models for both steel and concrete. The developed CFEM also considers nonlinear behaviour of studs by including the nonlinear load-slip and load-peel curves obtained from test results reported in the literature. In the CFEM, both the concrete and steel walls are modelled using 13-node subparametric shell elements, while the connecting studs between the two walls are modelled using 26-node contact elements using a smearing approach. Validation of the CFEM is conducted by modelling two composite slabs from the literature and comparing the results with their counterparts obtained from the conducted experiments. The CFEM is used to evaluate the deflections, stresses, and internal forces in the concrete and steel walls as well as steel studs. An Equivalent Section Method (ESM) for the analysis of composite tanks, which is based on using an equivalent single wall, is introduced. Deflections, stresses, and internal forces in the steel and concrete walls predicted using this simplified approach are compared to those predicted by the detailed finite element model.

The effect of 10-(2,5-dihydroxyphenyl)-9, 10-dihydro-9-oxa-10-phosphaphenanthrene- 10-oxide on liquid oxygen compatibility and cryogenic mechanical properties of epoxy resins

In the present study, 10-(2,5-dihydroxyphenyl)-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (ODOPB) was chemically incorporated into bisphenol A epoxy resin (EP) to improve liquid oxygen compatibility of the EP. Fourier transform infrared (FTIR) spectroscopy verified that ODOPB was successfully introduced into the molecular chain of bisphenol A EP. Thermogravimetric analysis confirmed that the ODOPB-modified EPs exhibited much better thermal stability than the pristine ones during the whole decomposition process under oxygen atmosphere. The 4,4′-diaminodiphenyl sulfone (DDS)-cured resins showed higher initial degradation temperature, and the 4,4′-diaminodiphenyl methane (DDM)-cured resins demonstrated better thermal stability at high temperature. The results of limited oxygen index measurements indicated that the modified EPs also possessed much improved flame retardancy. Furthermore, the enhanced liquid oxygen compatibility of the modified EPs characterized by the liquid oxygen impact test implied that improving thermal stability and flame retardancy of EPs was beneficial to enhance their liquid oxygen compatibility. X-ray photoelectron spectroscopy results demonstrated that the DDS-cured modified EPs had much higher reactivity with liquid oxygen compared to the DDM-cured ones. Mechanical performance tests indicated that the introduction of ODOPB could simultaneously improve the tensile properties and fracture toughness of the EPs at cryogenic temperature. Summarily, it can be considered that the ODOPB-modified EPs have the application prospect in the fabrication of the composite liquid oxygen tanks.

Multifunctional carbon nanotube coatings used as strain sensors for composite tanks

ABSTRACTThe modern strain sensors currently used in monitoring the structural properties of such tank structures suffer from a number of limitations, including a low level of sensitivity and detection. In this work, we present a novel method of structural monitoring utilizing a thin film of carbon nanotubes carefully deposited on carbon fiber composites. The nanotube film and raw material were first characterized via microscopy and spectroscopy techniques. Bowing of the tank wall was simulated by applying a three-point bend load test, which was found to strongly affect the electrical resistance of the carbon nanotube film. These measurements were very reproducible, as the film resistance returned to its original value each time that the load was slowly released. We believe that these highly sensitive carbon nanotube films are potential candidates as replacements for the current health-monitoring sensors.

A scanning spatial-wavenumber filter and PZT 2-D cruciform array based on-line damage imaging method of composite structure

The spatial-wavenumber filtering technique of Lamb wave is gradually applied for damage inspection of composite structure in recent years because it is an effective approach to distinguish the wave propagating direction and mode. But for on-line damage monitoring of composite structure by using spatial-wavenumber filter, the problem is how to realize the spatial-wavenumber filtering of Lamb wave when the wavenumber response cannot be measured or modeled. This paper proposes a scanning spatial-wavenumber filter and piezoelectric sensor (referred to as PZT) 2-D cruciform array based on-line damage imaging method of composite structure. In this method, a 2-D cruciform array constructed by two linear PZT arrays is placed on composite structure permanently to acquire Lamb wave damage scattering signal on-line. For one linear PZT array, a scanning spatial-wavenumber filter which does not rely on any modeled or measured wavenumber response is designed to filter the damage scattering signal at a designed wavenumber bandwidth to give out a wavenumber-time image. Based on the image, the wavenumber of the damage scattering signal projecting at the array can be obtained. The same process can be also applied to the other linear PZT array to get the wavenumber projecting at that array direction. By combining with the two projection wavenumbers, the damage can be localized without blind angle. The method is validated on an aircraft composite oil tank of variable thickness. The validation results show that the damage direction estimation error is less than 2° and the damage distance estimation error is around 20mm in the monitoring area of nearly 600mm×300mm. It indicates an acceptable performance of the damage imaging method for complex composite structure.

The influence of high-temperature sulfuric acid solution ageing on the properties of laminated vinyl-ester joints

A carbon fiber powder doped corrosion layer is used as an inner layer in large composite tanks to improve their chemical and wear resistance. In joints fabricated on site, this layer is embedded into the structure. This study evaluates the lap shear strength of specimens, simulating a laminated joint in between the corrosion layer and the inner joint laminate. Lap-shear tests were carried out for as-fabricated and aged laminates at room temperature and at elevated temperature. Ageing was carried out for half a year in a 95°C pressurized sulfuric acid solution. The tests showed that, after ageing, the room temperature shear strength remained unaltered but high-temperature shear strength was lowered. When the temperature increased, the failure location shifted from the interface between the doped layer and the joint laminate to the doped layer. Thermal analysis and microscopy were employed to clarify the reasons for the observed behavior.

Technical Diagnostics of the State of Composite Tanks of the Evaporators of Sulfuric Acid

The recycling of wastes of hydrolytic sulfuric acid (concentrated and purified in special evaporators) returns them into the technological process of production of mineral fertilizers. In this case, the main structural element of the technological equipment (the tank of the evaporator) suffers intense degradation and requires efficient diagnostics. It is shown that the service life of the evaporator strengthened with glass fibers of polymeric vinyl ester laminate and operating under the conditions of variable mechanical and thermal loads manly depends on the properties of the material of wear-resistant coating protecting the inner surface of the tank against abrasion by hard precipitates of the salts of monohydrates, iron sulfates, and magnesium sulfates.

Ảnh hưởng của tỷ lệ C:N khác nhau lên tăng trưởng, tỷ lệ sống và chất lượng của cá rô phi (Oreochromis niloticus) nuôi theo công nghệ biofloc

Applying biofloc techniques at different C:N ratios in culture tilapia was done in order to determine the appropriate C:N rate for better fish growth performance. The experiment was conducted with completely randomized design including five treatments of different C:N ratios (10, 15, 20, 15 and control treatment). Each treatment was triplicated. The mono-sex tilapia (8.43 g, 7.83 cm) were stocked at 40 fish/m3 in composite tanks (0.5 m3) with water salinity of 10‰. After 6 months of culture, the best fish growth performance was found in treatments of C:N=15 (282,8 g/fish and 1,37 %/day) and C:N=20 (267,9 g/fish and 1,36%/day). Fish production in treatments of C:N=15 (8.56 kg/m3) and C:N=20 (9.01 kg/m3) was significantly higher than that of control treatment. Moreover, the lowest FCR was found in treatments of C:N=20 (1.48) and C:N=15 (1.58). The survival rate was above 80% in treatment of C:N=20 and C:N=15. Fish sensory quality was not of significant difference among treatments.

Ứng dụng công nghệ biofloc để nuôi cá rô phi (Oreochromis niloticus) ở các độ mặn khác nhau

Applying biofloc techniques in rearing tilapia at different salinities was done in order to determine the appropriate salinities and culture systems for the better growth performance. The experiment was conducted with completely randomized design comprising five salinities (0, 5, 10, 15 and 20 ppt) combined with biofloc (adding carbohydrates at a ratio of C:N = 20:1) and without biofloc. Each treatment was triplicated. The mono-sex tilapia (1.38 g and 4.4cm) were stocked in composite tanks (0.5 m3) at the density of 40 fish/m3. After 7 months of culture, the environmental parameters such as temperature, pH, TAN and nitrite were in the suitable range for fish development. Besides, TAN levels in the biofloc applied treatments were significantly lower than those in treatments without biofloc (p

Using a glass-fibre reinforced polymer composite in the production of sustainable water storage tanks

The present work focuses on the use of the life cycle assessment (LCA) and life cycle costing (LCC) methodologies to evaluate environmental and economic impacts of polymers and polymer composites materials and products. Initially a literature review is performed in order to assess the scope and limitations of existing LCA and LCC studies on these topics. Then, a case study, based on the production of a water storage glass-fibre reinforced polymer (GFRP) composite storage tank, is presented. The storage tank was evaluated via a LCA/LCC integrated model, a novel way of analysing the life cycle (LC) environmental and economic performances of structural products. The overarching conclusion of the review is that the environmental and economic performances of polymers composites in nonmobile applications are seldom assessed and never in a combined integrated way.

Nghiên cứu ương giống tôm thẻ chân trắng (Litopenaeus vannamei) trong hệ thống biofloc với các chế độ che sáng khác nhau

This study purpose was to find out the suitable light intensity range for Biofloc formation, survival rate and growth rate for nursing of white leg shrimp (Litopenaeus vannamei) postlarvae. The experiment included 3 treatments of different light intensities of (1) not cover shading net (control treatment), (2) cover with 1 layer of shading net, (3) cover with 3 layers of shading net. Composite tanks of 500 L containing 250 L of brackish water (15ppt) were used. White leg shrimp (PL15) were stocked at 2000 inds/m3 with the weight of 0.03 g/PL15 in strong aeration. Wheat flour and soya bean meal were used at C/N ratio of 15:1. After 6 weeks of experiment, nursing of white leg shirmp in Biofloc system with different light intensities showed strong effects on biofloc formation, growth performances and survival of shrimp. Particularly, total length and weight of shrimp were highest in the treatment 2 (5.35 cm and 1.4 g, respectively) and lowest in the control treatment (4.5 cm and 0.85g). In addition, the highest survival rate (58.07 %) and highest yield (1,161 shrimp/m3)was also found in the treatment 2. The results shown that treatment cover with 1 net layer with appropriate light intensity of 43-308 Lux gave the best results in water quality parameters, growth and survival of shrimp.

Evaluation of an ionic liquid-based epoxy after exposure on the MISSE-8 Carrier

An ionic liquid-based epoxy was evaluated after more than two years of continual nadir space exposure on the MISSE-8 sample rack outside of the International Space Station. In addition to space radiation, atomic oxygen and vacuum space exposure the samples also experienced approximately 12,500 thermal cycles between ∼−40°C and +40°C. The returned samples exhibited no cracking or de-bonding from the aluminum discs to which the epoxy was initially applied; there was a slight change in color, and a miniscule variance in before-and-after weight was measured. Microscopic examination revealed some slight deformities, dimpling, and deposits on the exposed surfaces. These are put into the context of an on-going effort to develop viable carbon-fiber based composite tanks for, but not inclusively, cryogenic liquid containment.

Design tool for offgrid hydrogen refuelling systems for aerospace applications

To develop an environmentally acceptable refuelling solution for fuel cell-powered unmanned aerial systems (UASs) to operate in remote areas, hydrogen fuel must be produced on-site from renewable energy sources. This paper describes a Matlab-based simulation tool specifically developed to pre-design offgrid hydrogen refuelling systems for UAS applications. The refuelling system comprises a high concentrated PV array (CPV), an electrolyser, a hydrogen buffer tank and a diaphragm hydrogen compressor. Small composite tanks are also included for fast refuelling of the UAV platforms at any time during the year. The novel approach of selecting a CPV power source is justified on the basis of minimizing the system footprint (versus flat plat or low concentration PV), aiming for a containerized remotely deployable UAS offgrid refuelling solution.To validate the simulation tool a number of simulations were performed using experimental data from a prototype offgrid hydrogen refuelling station for UAVs developed by Boeing Research & Technology Europe. Solar irradiation data for a selected location and daily UAS hydrogen demands of between 2.8 and 15.8Nm3 were employed as the primary inputs, in order to calculate a recommended system sizing solution and assess the expected operation of the refuelling system across a given year. The specific energy consumption of the refuelling system obtained from the simulations is between 5.6 and 8.9kWhe per kg of hydrogen delivered to the UAVs, being lower for larger daily hydrogen demands. Increasing the CPV area and electrolyser size in order to supply higher daily hydrogen demands (e.g., above 10Nm3 H2 per day) improves the system operability. However this can imply excessive system size and costs, jeopardizing the techno-economic feasibility of a remotely deployable off-grid refuelling solution.