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At least 19 records

MODELS FOR ESTIMATING THE AUTOFRETTAGE PRESSURE AND RESIDUAL STRESSES IN WALLS OF TYPE 2 PRESSURE VESSELS

Autofrettage is a manufacturing process used during fabrication of Type 2 pressure vessels designed for usage at high pressures to enhance the fatigue life. The process locks high compressive residual stresses in the vessel’s liner wall that reduce the maximum and the mean stress during service loading. To achieve a consistent residual stress profile across the wall of the vessel, the choice of autofrettage pressure is critical. Several finite element analyses runs were conducted to estimate the correct autofrettage pressure that is a function of the yield strength of the liner material, the wall thickness, and the outside diameter of the liner for a wrap thickness of 17.06 mm (48 wire layers). From the finite element analyses results, models were developed to estimate the correct autofrettage pressure and the residual stress distribution across the liner wall as a function of the yield strength of the liner material, the wall thickness, and the outside diameter of the liner.

08 HYDROGEN↗

Durable Low-Cost Pressure Vessels for Bulk Hydrogen Storage

Long-duration energy storage (LDES) in the form of gaseous hydrogen is vital for fossil fuel power plants to reduce frequent shutdowns and rapid start-ups. It's also crucial in renewable energy power plants for grid stabilization. WireTough Cylinders (WTC) has developed a Type II-S pressure vessel that uses steel liners that are hoop-wrapped with multiple layers of high-strength, cost-effective, and readily available steel wires. This design enables the vessel to withstand significantly higher pressures. It addresses hydrogen embrittlement issues and cyclic loading from repeated pressurization and depressurization during service. The WireTough design is cost-efficient, robust, and fatigue-resistant (with a 30-year design life) and is ASME certified for ground storage of hydrogen at a maximum operating pressure (MOP) of 350 bar and a design pressure of 500 bar. The cylinder has a 645 mm outside diameter and a water capacity of 1,715 liters, capable of storing 40.7 KG of hydrogen at MOP. Two prototypes were successfully produced to showcase the manufacturing technologies, with one being certified under ASME Section VIII Division 3 rules. Preliminary design work for a similar Type II-S vessel with a 500 bar MOP was also completed. The 350 bar and 500 bar Type II-S vessels were shown respectively to be 47.5% to 60% more cost-effective and 55% and 62.5% lighter based on per KG of hydrogen stored, when compared with their Type 1 counterparts.

08 HYDROGEN↗

Lianas and Trees From a Seasonally Dry and a Wet Tropical Forest Did Not Differ in Embolism Resistance but Did Differ in Xylem Anatomical Traits in the Dry Forest

One of the most prominent changes in neotropical forests has been the increase in abundance and size of lianas. Studies suggest that lianas have more acquisitive strategies than trees, which could allow them to take advantage of water more effectively when it is available in water-limited forests, but few studies compared across growth form (i.e., lianas vs. trees) and forest type (i.e., wet vs. seasonally dry). We measured hydraulic and anatomical traits of co-occurring lianas and trees that convey drought resistance (xylem embolism resistance and intervessel pit membranes) and water transport capacity (xylem vessel diameter and density) in a seasonally dry and a wet evergreen tropical forest to address: (1) Are there differences between vulnerability to embolisms (P 50 —water potential at 50% loss of hydraulic conductivity) and hydraulic safety margins (HSM) across growth form and forest type? (2) How do vessel diameter and density vary across growth form and forest type? (3) Are there differences in xylem intervessel pit membrane thickness across growth form and forest type and does it predict xylem embolism vulnerability in trees and lianas? We examined hydraulic and xylem anatomical traits of 32 species—eight lianas and eight trees in each forest type. We found no difference in P 50 and HSMs between lianas and trees and between the wetter and drier forest. Dry forest lianas had 81% greater maximum vessel diameter and 125% greater range in vessel diameter sizes than dry forest trees but, there was no significant difference between life forms in the wet forest. Dry forest species had 50% greater vessel density and 30% greater maximum pit membrane thickness than wet forest ones. Maximum pit membrane thickness was correlated to P 50 and HSMs. The main difference between lianas and trees occurred in the dry forest, where lianas had larger maximum xylem vessel size than trees, implying that they have proportionally greater hydraulic conductive capacity than the trees in seasonal forests.

Smith-Martin, Chris M.↗

Hybrid Inflatable Pressure Vessel

Figure 1 shows a prototype of a large pressure vessel under development for eventual use as a habitable module for long spaceflight (e.g., for transporting humans to Mars). The vessel is a hybrid that comprises an inflatable shell attached to a rigid central structural core. The inflatable shell is, itself, a hybrid that comprises (1) a pressure bladder restrained against expansion by (2) a web of straps made from high-strength polymeric fabrics. On Earth, pressure vessels like this could be used, for example, as portable habitats that could be set up quickly in remote locations, portable hyperbaric chambers for treatment of decompression sickness, or flotation devices for offshore platforms. In addition, some aspects of the design of the fabric straps could be adapted to such other items as lifting straps, parachute straps, and automotive safety belts. Figure 2 depicts selected aspects of the design of a vessel of this type with a toroidal configuration. The bladder serves as an impermeable layer to keep air within the pressure vessel and, for this purpose, is sealed to the central structural core. The web includes longitudinal and circumferential straps. To help maintain the proper shape upon inflation after storage, longitudinal and circumferential straps are indexed together at several of their intersections. Because the web is not required to provide a pressure seal and the bladder is not required to sustain structural loads, the bladder and the web can be optimized for their respective functions. Thus, the bladder can be sealed directly to the rigid core without having to include the web in the seal substructure, and the web can be designed for strength. The ends of the longitudinal straps are attached to the ends of the rigid structural core by means of clevises. Each clevis pin is surrounded by a roller, around which a longitudinal strap is wrapped to form a lap seam with itself. The roller is of a large diameter chosen to reduce bending of the fibers in the strap. The roller also serves to equalize the load in the portions of the strap on both sides of the clevis pin. The lap seam is formed near the clevis by use of a tapered diamond stitch: This stitch is designed specifically to allow fibers in the stitch and strap to relax under load in such a manner that the load becomes more nearly evenly distributed among all fibers in the stitch region. Thus, the tapered diamond stitch prevents load concentrations that could cause premature failure of the strap and thereby increases the strength of the strap/structural-core joint. The lap seam can be rated at >90 percent of the strength of the strap material.

Raboin, Jasen↗

Rational design of semi-interpenetrating network based on hyperbranched polyglycerol grafted MXene/polyurethane–epoxy for compressed hydrogen storage

Here, hydrogen (H 2 ) energy has emerged as a promising alternative in the automotive sector to replace fossil fuel; however, its storage with volumetric efficiency remains a challenge. The latest type IV storage vessel featuring a polymeric liner with composite overwrap incurs hydrogen saturation, which eventually causes failure. To prevent the H 2 dissolution in the liner, we have developed a barrier coating comprised of polyurethane/epoxy semi-interpenetrating network (S-IPN) combined with hyperbranched polyglycerol grafted MXene (h-MXene). The hyperbranched structure facilitated the dispersion of MXene in the coating solution by enhancing the exfoliation and improved the polymer filler interaction by forming covalent and H-bonding through end-terminal hydroxyl groups. Leveraging the dense network of S-IPN combined with the dispersed layer structured h-MXene significantly increased the tortuosity of the spray-coated barrier film applied to the nylon 6 liner. The coating exhibited a 90 % reduction in the H 2 gas permeability at only 2 wt% h-MXene concentration, which further improved to above 98 % at 10 wt% loading. Additionally, the h-MXene considerably improved the adhesion with the liner even in a highly stretched condition, signifying the durability of the coating under cyclic pressurization and depressurization of the storage vessel.

08 HYDROGEN↗

Final Design of the Production SSR1 Cryomodule for PIP-II Project at Fermilab

This contribution reports the design of the production Single Spoke Resonator Type 1 Cryomodule (SSR1 CM) for the PIP-II project at Fermilab. The innovative design is based on a structure, the strongback, which supports the coldmass from the bottom, stays at room temperature during operations, and can slide longitudinally with respect to the vacuum vessel. The Fermilab style cryomodule developed for the prototype Single Spoke Resonator Type 1 (pSSR1), the prototype High Beta 650 MHz (pHB650), and preproduction Single Spoke Resonator Type 2 (ppSSR2) cryomodules is the baseline of the present design. The focus of this contribution is on the results of calculations and finite element analyses performed to optimize the critical components of the cryomodule: vacuum vessel, strongback, thermal shield, and magnetic shield.

43 PARTICLE ACCELERATORS↗

Particle size distribution of suspended solids in the Chesapeake Bay entrance and adjacent shelf waters

Characteristics of suspended solids, including total suspended matter, total suspended inorganics, total suspended organics, particle size distribution, and the presence of the ten most prominent particle types were determined. Four research vessels simultaneously collected samples along four transects. Samples were collected within a 2-hour period that coincided with the maximum ebb penetration of Chesapeake Bay outwelling. The distribution of primary and secondary particle size modes indicate the presence of a surface or near-surface plume, possibly associated with three sources: (1) runoff, (2) resuspension of material within the Bay, and/or (3) resuspension of material in the area of shoals at the Bay mouth. Additional supportive evidence for this conclusion is illustrated with ocean color scanner data.

Byrnes, M. R.↗

Common pressure vessel battery performance

Performance tests run on two common pressure vessel type nickel hydrogen batteries are described and the results presented. The study included: (1) charge retention tests, (2) synchronous eclipse season cycling tests, and (3) temperature differential tests.

Otzinger, B.↗

Preservation of high-pressure volatiles in nanostructured diamond capsules

High pressure induces dramatic changes and novel phenomena in condensed volatiles(1,2) that are usually not preserved after recovery from pressure vessels. In this study we report a process that pressurizes volatiles into nanopores of type 1 glassy carbon precursors, converts glassy carbon into nanocrystalline diamond by heating and synthesizes free-standing nanostructured diamond capsules (NDCs) capable of permanently preserving volatiles at high pressures, even after release back to ambient conditions for various vacuum-based diagnostic probes including electron microscopy. As a demonstration, we perform a comprehensive study of a high-pressure argon sample preserved in NDCs. Synchrotron X-ray diffraction and high-resolution transmission electron microscopy show nanometre-sized argon crystals at around 22.0 gigapascals embedded in nanocrystalline diamond, energy-dispersive X-ray spectroscopy provides quantitative compositional analysis and electron energy-loss spectroscopy details the chemical bonding nature of high-pressure argon. The preserved pressure of the argon sample inside NDCs can be tuned by controlling NDC synthesis pressure. To test the general applicability of the NDC process, we show that high-pressure neon can also be trapped in NDCs and that type 2 glassy carbon can be used as the precursor container material. Additional experiments on other volatiles and carbon allotropes open the possibility of bringing high-pressure explorations on a par with mainstream condensed-matter investigations and applications.

36 MATERIALS SCIENCE↗

Lipid synthesis under hydrothermal conditions by Fischer-Tropsch-type reactions

Ever since their discovery in the late 1970's, mid-ocean-ridge hydrothermal systems have received a great deal of attention as a possible site for the origin of life on Earth (and environments analogous to mid-ocean-ridge hydrothermal systems are postulated to have been sites where life could have originated or Mars and elsewhere as well). Because no modern-day terrestrial hydrothermal systems are free from the influence of organic compounds derived from biologic processes, laboratory experiments provide the best opportunity for confirmation of the potential for organic synthesis in hydrothermal systems. Here we report on the formation of lipid compounds during Fischer-Tropsch-type synthesis from aqueous solutions of formic acid or oxalic acid. Optimum synthesis occurs in stainless steel vessels by heating at 175 degrees C for 2-3 days and produces lipid compounds ranging from C2 to > C35 which consist of n-alkanols, n-alkanoic acids, n-alkenes, n-alkanes and alkanones. The precursor carbon sources used are either formic acid or oxalic acid, which disproportionate to H2, CO2 and probably CO. Both carbon sources yield the same lipid classes with essentially the same ranges of compounds. The synthesis reactions were confirmed by using 13C labeled precursor acids.

Non-NASA Center↗

Organic fiber/epoxy pressure vessels

We evaluated the performance of an organic fiber in an epoxy matrix by winding 20-cm diam spherical and cylindrical pressure vessels of various designs. For the spherical vessels, we used soft aluminum liners 0.76 mm thick for a double boss design and 2 mm thick for a single boss design. For the cylindrical vessels, we used both 0.5-mm rubber liners and 0.76-mm soft aluminum liners. Vessels of both types were tested for burst pressure and cyclic fatigue at room temperature and liquid hydrogen temperature. The effects of temperature and vessel shape on the vessel performance factor were negligible. Our vessel fatigue data were marred by premature failure of the liners.

Chiao, T. T.↗

Final Design Of The Pre-production SSR2 Cryomodule For PIP-II Project At Fermilab

The present contribution reports the design of the pre-production Single Spoke Resonator Type 2 Cryomodule (ppSSR2 CM), developed in the framework of the PIP-II project at Fermilab. The innovative design is based on a structure, the strongback, which supports the coldmass from the bottom, stays at room temperature during operations, and can slide longitudinally with respect to the vacuum vessel. The Fermilab style cryomodule developed for the prototype Single Spoke Resonator Type 1 (pSSR1) and the prototype High Beta 650 MHz (pHB650) cryomodules is the baseline of the current design, which paves the way for production SSR1 and SSR2 cryomodules for the PIP-II linac. The focus of this contribution is on the results of calculations and finite element analysis performed to optimize the critical components of the cryomodule: vacuum vessel, strongback, thermal shield, and magnetic shield.

43 PARTICLE ACCELERATORS↗

Design Guidance for High Temperature Concentrating Solar Power Components

This report provides guidance for the design of components for concentrating power facilities operating at high temperatures and undergoing high, secondary thermal stresses relative to the applied primary pressure stress. The design rules were developed for the design of Generation 3 CSP tubular receivers manufactured from Alloy 740H, but are generally applicable to a wide range of component types undergoing similar loads. Part 1 of the report provides procedural design rules for components to be used in conjunction with the 2019 edition of the ASME Boiler & Pressure Vessel Code. Part 2 provides corresponding design data for Alloy 740H. Part 3 of the report is a commentary describing the rationale behind the design rules and the data underlying the design material properties. Finally, Part 4 provides an extensive set of worked sample problems detailing the application of the rules to CSP components.

24 POWER TRANSMISSION AND DISTRIBUTION↗

Vapors-liquid phase separator

The use of porous plugs, mostly with in the form of passive devices with constant area were considered as vapor-liquid phase separators for helium 2 storage vessels under reduced gravity. The incorporation of components with variable cross sectional area as a method of flow rate modification was also investigated. A particular device which uses a shutter-type system for area variation was designed and constructed. This system successfully permitted flor rate changes of up to plus or minus 60% from its mean value.

Frederking, T. H. K.↗

Correlations Between Metallurgical Characterization Studies, Exploratory Mechanical Tests, and Continuum Mechanics Approaches to Constitutive Equations

Austenitic stainless steels, such as types 316 and 304, are widely used as pressure vessel materials in the temperature range of 425 to 650 C. Stainless steel specimens were tested to rupture at two different stress levels sigma and sigma 2 sigma 1 sigma 2) to establish the normal stain-time behavior. A subsequent test was performed in which the specimen was crept at the higher stress (sigma 1) to the beginning of the secondary stage of creep, presumed to be the strain/time conditions at which a steady state microstructure is developed, and then the stress was reduced to the lower level (sigma 2). The associated microstructure, and significance of this microstructure on the creep strain-hardening model for variable uniaxial loads were assesed and found to be consistent with the use of creep-recovery models at high stresses and temperatures and strain-hardening models at low stresses and tempertures.

Moteff, J.↗

Interaction of Vascular Smooth Muscle Cells Under Low Shear Stress

The blood vessel wall consists of three cellular layers, an outer adventitial, a middle medial and an inner intimal layer. When the blood vessel forms in the embryo it begins as a tube composed of a single cell type called endothelial cells. Over time, other cells are recruited from the surrounding tissue to form additional layers on the outer surface of the endothelial tube. The cells that are recruited are called mesenchymal cells. Mesenchymal cells are responsible for the production of connective tissue that holds the blood vessel together and for developing into vascular smooth muscle cells that are responsible for regulating the diameter of the vessel (1) and therefore, blood flow. In a fully developed blood vessel, the endothelial cells make- up the majority of cells in the intimal layer while the mesenchymal cells make-up the majority of cells in the medial and adventitial layers. Within the medial layer of a mature vessel, cells are organized into multiple circular layers of alternating bands of connective tissue and cells. The cell layer is composed of a mixture of mesenchymal cells that have not developed into smooth muscle cells and fully developed smooth muscle cells (2). The assembly and organization of complex tissues is directed in part by a signaling system composed of proteins on the cell surface called adhesion molecules. Adhesion molecules enable cells to recognize each other as well as the composition of the connective tissue in which they reside (3). It was hypothesized that the different cell types that compose the vascular wall possess different adhesion molecules that enable them to recognize each other and through this recognition system, form the complex layered organization of the vascular wall. In other words, the layered organization is an intrinsic property of the cells. If this hypothesis is correct then the different cells that make up the vessel wall, when mixed together, should organize themselves into a layered structure resembling an intact blood vessel. Experiments described below were designed to test this hypothesis.

Seidel, Charles L.↗