bluuebunny/crossref_metadata_2025_split huggingface dataset:
Research on Fire Test Method of High Pressure Hydrogen Storage Cylinders for Transportation
Authors: Li Jun , Li Xiang , Li Jiepu , Zhao Baodi , Gu Chunlin , Guan Jian 
Published: October 2021

Abstract
As important equipment in the entire hydrogen industry chain, composite hydrogen storage cylinders for transportation have developed rapidly in recent years. The fire test is used to verify the explosion resistance of gas cylinders under specified fire conditions. Compared to steel gas cylinder, composite gas cylinder is more dangerous in the fire condition. The wound layer, as the main pressure-bearing structure of the composite hydrogen storage cylinder, is inflammable. In the case of fire, the mechanical properties of the cylinder will degrade quickly due to the high temperature. If the gas inside the cylinder cannot be discharged in time, the cylinder explosion will occur. Currently, some relevant standards or standard drafts have been drawn up by the international organizations, which are useful for formulating Chinese standard for hydrogen storage cylinders for transportation. The applicable scope of the standards was discussed in this paper, such as composite cylinder type, working pressure, nominal volume and design life, etc. The fire test methods of composite gas cylinders in various standards were compared and analyzed, such as experiment method, cylinder placement method, cylinder filling requirements, fuel selection, fire source setting, temperature measurement requirements, and qualified indicators, etc. Finally, the challenges for development of composite hydrogen storage cylinders and compressed hydrogen storage systems in China were proposed.
Evaluation of Brittle Crack Arrest Toughness for Highly-Irradiated Reactor Pressure Vessel Steels
Authors: Iwata Keiko , Hata Kuniki , Tobita Tohru , Hirota Takatoshi , Takamizawa Hisashi , Chimi Yasuhiro , Nishiyama Yutaka 
Published: October 2021

Abstract
The crack arrest fracture toughness, KIa, values for highly-irradiated reactor pressure vessel (RPV) steels are estimated according to the linear relationship between crack arrest toughness reference temperature, TKIa, and the temperature corresponding to a fixed arrest load, equal to 4 kN, TFa4kN, obtained by instrumented Charpy impact test. The relationship between TKIa derived from the instrumented Charpy impact test and fracture toughness reference temperature, To, was expressed as an equation proposed in a previous study. The coefficients in the equation could be fine-tuned to obtain a better fitting curve using the present experimental data and previous KIa data. The KIa curve for RPV;A533B class 1 steels irradiated up to 1.3 × 1020 n/cm2 (E &gt; 1 MeV) was compared with a KIR curve defined in JEAC4206-2016. The KIR curve was always lower than the 1%ile curve of KIa for these irradiated RPV steels. This result indicates that the conservatism of the method defined in JEAC4206-2016 to evaluate KIa using the KIR curve is confirmed for highly-irradiated RPV steels.
Crack Growth Resistance of Actual Pipe Weldments Exposed to a High Pressure Mixture of Hydrogen and Natural Gas
Authors: Benoit Guillaume , Bertheau Denis , Hénaff Gilbert , Alvarez Laurent 
Published: October 2021

Abstract
In a context of reduction of greenhouse gas emission, the development of hydrogen as an energy carrier implies the transport of large quantity of hydrogen gas over long distances. The option of using the existing Natural Gas (NG) network raises the question of the amount of hydrogen gas that can be blended with natural gas while ensuring safe operating conditions for the pipe, especially in presence of crack-like defects. With this respect, the present study was undertaken in order to get a first assessment of the impact of the hydrogen gas content in natural gas on the crack growth resistance of pipeline girth welds. With this aim, fracture toughness and fatigue crack propagation tests were carried out at RT on a servo-hydraulic machine equipped with a pressure vessel. The CT samples used in these tests were extracted from different actual circular welds (respectively 350 and 900 mm pipe diameter, 7 and 13 mm thickness) representative of those present in the network so that the crack plane is located in the joint (Weld Centre Line so far). Two couples of steel and welding process were studied, namely a modern pipe steel L485 (X70) welded by mechanized welding process (GMAW) and a vintage pipe (X60) carbon steel with a manual cellulosic electrode process (SMAW). Two environmental conditions were considered so far, namely representative NG including 9 minor species and a 25%H -NG blend with a total pressure of 8.5 MPa. The fracture toughness for both types of welds results indicate no significant effect of hydrogen on the K values, while the plastic opening and the CTOD values are affected at different degrees. Besides, fatigue crack growth rates are enhanced by more than one order of magnitude in the 25%H -NG mixture in the high ΔK region as compared to NG. Fractographic observations are presented to support these results.
An Assessment of Engineering Knowledge Management Regarding Retention and Maintenance
Authors: Farrell Ronald S. , Ezekoye L. Ike 
Published: October 2021

Abstract
The importance for an organization to retain and maintain business knowledge is well known. As such, there are many knowledge management (KM) resources available including educational materials and tools for general business practices such as enterprise computer and cloud applications. Despite all the available resources, there remain challenges within KM organization strategies and adoption practices that need attention. For instance, author Jay Liebowitz warns in his book, Knowledge Retention: Strategies and Solutions, that organizations are experiencing knowledge bleed as baby boomers retire and younger workers take over the work. The focus of this paper is twofold, (a) evaluate Liebowitz’s warning within the practice of engineering, and (b) assess the challenge of retaining and maintaining engineering expertise for the long term. The authors, each with over forty years of engineering experience, have observed that engineering departments are aware of the benefit of capturing current and legacy knowledge but often fail to do so. Instead, the habitual practice of business as usual remains the default. For instance, the capture of enterprise engineering methodology is attempted only when experienced and seasoned expert engineers are very close to retiring when it is generally too late to be effective, that is if any exit strategy exists at all. In addition, the maintenance of crucial engineering tools, especially those developed in house, relies on very few product line expert engineers with no one to assume the highly technical role upon attrition. A possible consequence of this habitual practice is to frustrate younger workers who are asked to assume an expert’s role too soon and unprepared. This frustration frequently leads young talents in search of competing firms that do a better job with their engineering KM. Instead of ineffective practices, the authors explore strategies for engineering knowledge retention and for putting good practice into place. Additionally, potential benefits to the company are discussed with regards to efficient knowledge capture and the grooming and retention of future expert engineers.
Temperature Dependent Failure Behaviour of Components Containing Crack Fields: An Experimental and Numerical Approach
Authors: Weihe Stefan , Stumpfrock Ludwig , Weber Ulrich , Gauder Patrick , Seidenfuss Michael 
Published: October 2021

Abstract
The indications of a high quantity of cracks from non-destructive testing measurements were determined in a root cause analysis as hydrogen flakes positioned in segregated zones in the base material of pressure vessels of Belgian nuclear power plants. Because of the laminar and quasi-laminar orientations of this hydrogen flakes with an inclination up to 16° to the pressure retaining surface the crack tips undergo predominantly mixed-mode loading conditions under internal pressure and the induced stress and strain fields of the single crack tips influence each other. In a former paper, the failure behavior of crack fields under mixed mode loading conditions was investigated at RT (Room Temperature) and −100°C, the upper shelf and the lower transition phase of the steel 22NiMoCr3-7, respectively. In this paper, the failure behavior of crack fields is investigated for many different levels of material toughness (from to upper shelf to the lower shelf region) on experiments with different artificial manufactured crack fields. Therefore, numerical simulations are carried out with extended micromechanical based damage mechanics models. For the description of ductile failure the Rousselier model is used and the Beremin model to calculate the probability of cleavage fracture. To account the sensitivity for low stress triaxiality damage by shear loading, the damage mechanics model was enhanced with a term to account for damage evolution by shear. For numerical simulations in the transition region of brittle-to-ductile failure a coupled damage mechanics model (enhanced Rousselier & Beremin) will be used. In this paper, the current state of the ongoing research project is presented.
Comparative Assessments of Different Leakage-Rate Models for ATLAS+
Authors: Williams P. T. , Bass B. R. , Dillström P. , Gill P. , Daniels B. , Lammert R. , Wackenhut G. 
Published: October 2021

Abstract
In support of the Euratom research and training program Advanced Structural Integrity Assessment Tools for Safe Long Term Operation (ATLAS+), this paper presents a comparative assessment of both conservative and best-estimate leakage-rate models carried out using the recently-developed Leak Analysis of Piping – OCI (LOCI™) code. Studies are reported comparing the LOCI™ results with the XPIPE™ code developed by Materialprüfungsanstalt (MPA) Universität Stuttgart and a new leakage-rate code developed by Jacobs. All participants in this study are members of the ATLAS+ consortium.
In the context of a leak-before-break (LBB) assessment where emphasis is placed on the detection of small leakage rates, the distinction between conservative and best-estimate models can be very important. This classification can provide guidance on where these models can be appropriately applied in terms of understanding margins and uncertainties. Country-specific regulatory requirements for an LBB assessment can also play an important role in model selection. A conservative leakage-rate model is required to consistently underestimate the actual leakage rate and is typically applied in deterministic procedures. A best-estimate leakage-rate model places greater emphasis on predictive accuracy. In a probabilistic framework, the model’s estimated solutions can serve as a measure of central tendency (mean, median, or mode) for a prescribed statistical distribution characterizing the uncertainties in leakage-rate predictions.
In a more general probabilistic analysis, model inputs and their associated statistical distributions are sometimes proposed which have conservative values for parameters to ensure that some extreme cases are not underrepresented. However, conservatism can lead to overestimates of the probability of leakage or rupture and, thereby, invalidate the model. Moreover, conservatism at a subsystem level could potentially become non-conservative when implemented at the system or framework level.
Development and Validation of Radiant Heat Systems to Test RAM Packages Under Non-Uniform Thermal Environments
Authors: Mendoza Hector , Gill Walter , Figueroa Victor G. , Sanborn Scott 
Published: October 2021

Abstract
Certification of radioactive material (RAM) packages for storage and transportation requires multiple tiers of testing that simulate accident conditions in order to assure safety. One of these key testing aspects focuses on container response to thermal insults when a package includes materials that decompose, combust, or change phase between −40 °C and 800 °C. Thermal insult for RAM packages during testing can be imposed from a direct pool fire, but it can also be imposed using a furnace or a radiant heat system. Depending on variables such as scale, heating rates, desired environment, intended diagnostics, cost, etc., each of the different methods possess their advantages and disadvantages. While a direct fire can be the closest method to represent a plausible insult, incorporating comprehensive diagnostics in a controlled fire test can pose various challenges due to the nature of a fire. Radiant heat setups can instead be used to impose a comparable heat flux on a test specimen in a controlled manner that allows more comprehensive diagnostics. With radiant heat setups, however, challenges can arise when attempting to impose desired non-uniform heat fluxes that would account for specimen orientation and position in a simulated accident scenario. This work describes the development, implementation, and validation of a series of techniques used by Sandia National Laboratories to create prescribed non-uniform thermal environments using radiant heat sources for RAM packages as large as a 55-gallon drum.
Validation of Modern Finite Analysis Methods for Glassy Polymers Using Historical Studies
Authors: Kemper Bart 
Published: October 2021

Abstract
The current method for designing acrylic pressure vessel components relies upon an empirical method developed through experimentation during the 1960’s and 70’s. The method is detailed in ASME PVHO-1, Safety Standard for Pressure Vessels for Human Occupancy. One of the factors restricting the design methodology to experimental correlation was the structural dimensions. Thick wall pressure vessel geometry prevented the use of conventional Section VIII pressure vessel calculations, which assumes thin wall pressure vessels. Early Finite Element Analysis (FEA) models of acrylic windows could not be validated through experimentation. This was attributed to the viscoelastic properties of acrylics. The resulting experiment-based PVHO-1 Safety Standard has a proven safety record but is not readily updated. This paper re-examines some of the work used to develop PVHO-1 to demonstrate modern nonlinear FEA and V&V techniques can predict the results of the original work. In doing so, this work also validates the use of FEA going forward for Design By Analysis (DBA) using Verification and Validation (V&V) for newer materials, shapes, and applications.
Explicit Finite Element Fatigue Crack Growth Analysis of An Instrumentation Ring Under Thermal Transient Loading
Authors: Selling Joshua B. B. , Holliday James E. , Damiani Thomas M. 
Published: October 2021

Abstract
ASME PVP conference papers from 2007 and 2008 (References [1] and [2]) discuss fatigue analyses related to 304 stainless steel instrumentation spacer rings (rings) that had cracked while installed in a thermal fatigue test loop. The rings contain circular radial penetrations extending through the ring that allow access for instrumentation probes to monitor the fluid temperature and pressure. Routine inspection of the test loop revealed actively growing cracks in each port that appeared to start near the inner diameter (ID) of the ring. In this work, three-dimensional finite element analysis (FEA) thermal and fully-elastic structural Abaqus models were made from the available test measurements. The commercial crack modeling software, Franc3D, was used to complete an M-integral based fatigue crack growth (FCG) analysis. An assumed initial crack was inserted in a single port of interest near the ID of the FEA model. The crack was explicitly grown in an automated fashion over iterative growth steps. The explicit FCG analysis was able to match the directional path and final flaw size seen in the destructive evaluation metallographic images of the rings with the assumed input parameters exceptionally well, including shifting directions and splitting the crack without need of user input. The results of this work indicate that an explicit FCG analysis is feasible for a non-trivial thermal-structural problem.
Qualification Challenges for Additive Manufacturing in High Temperature Nuclear Applications
Authors: McMurtrey Michael , Messner Mark 
Published: October 2021

Abstract
There is an increasing interest in using additive manufacturing for structural materials, including pressure-retaining components. This requires that the manufacturing methods be included in Codes and Standards, such as the Boiler Pressure Vessel Code. This work is already moving forward with the development of a Section III Division 1 Code Case to include 316 stainless steel that is manufactured using powder bed fusion, an additive manufacturing technique. However, Code Cases will become significantly more challenging when time-dependent properties must be considered, such as in Section III, Division 5. Section III, Division 5 requires design models based on creep as well as creep-fatigue interaction. Testing for this is time intensive and costly. Additive manufacturing properties are a result of feedstock material as well as processing methods/parameters. The individual machines take what used to be centralized material fabrication (into large plates of castings) and spread the process out to many separate facilities. This decentralized fabrication, paired with the rapidly changing landscape of additive techniques and equipment manufacturers, has created difficulty in quality control and producing code cases. For low-temperature code cases, this has been circumvented by requiring witness specimens that meet specified property requirements. Additional witness specimens to cover time-dependent properties would significantly increase the cost and delay processes, so similar methods may not be effective for high temperature applications. This paper covers fabrication and modeling/simulation challenges associated with qualification of additive manufacturing processes for high-temperature structural materials.
Application of Leak-Before-Break to Small Diameter Stainless Steel Piping in PWRs
Authors: Cofie Nathaniel G. , Dedhia Dilip , Shim Do Jun 
Published: October 2021

Abstract
Traditionally, leak-before-break (LBB) analysis has been applied to large diameter main loop piping in pressurized water reactors (PWRs) to address the dynamic effects of pipe break required by the General Design Criteria 4, Appendix A of 10CFR50.
Recently, however, LBB is being sought for Class 1 pressure boundary piping systems such as the safety injection and residual heat removal systems which have small diameter piping (12-inch NPS and less) to mitigate the effect of dynamic loads on reactor internals and other concerns. In NUREG-1061, Volume 3, it is stated that LBB approach means the application of fracture mechanics to demonstrate that high energy fluid piping is unlikely to experience double-ended ruptures or their equivalent as longitudinal or diagonal splits. In application of traditional LBB to large diameter piping, only circumferential flaws are considered since it is generally believed that leaks through axial flaws for such piping are relatively large in comparison to circumferential flaws. However, this may not be the case for small diameter piping.
This paper examines the application of LBB to small diameter stainless steel piping in PWRs by determining the leak rate requirements to meet the criteria specified in SRP 3.6.3 and NUREG-1061, Volume 3 for both circumferential and axial flaws.
Effect of Hydrogen on Tensile Properties of 304L Stainless Steel at Cryogenic Temperatures
Authors: Merkel Daniel R. , Nickerson Ethan K. , Seffens Robert J. , Simmons Kevin L. , San Marchi Chris , Kagay Brian J. , Ronevich Joseph A. 
Published: October 2021

Abstract
Safe and efficient hydrogen storage and distribution are key attributes to realizing hydrogen as an alternative energy carrier to traditional fossil fuels. To this end, cryogenic liquid and cryo-compressed gaseous hydrogen are considered high energy density alternatives to ambient temperature gas. However, these alternatives have significant material demands to overcome extreme temperature (20 K) and pressure (700 bar) as well as hydrogen effects. Austenitic stainless steels are widely used for cryogenic pressure vessels owing to relatively high ductility even at 4 K. However, the influence of hydrogen on mechanical properties at cryogenic temperatures has rarely been studied. In this study, the tensile properties of 304L austenitic stainless steel with internal hydrogen were evaluated at 20 K, 77 K, and 113 K. Test specimens were saturated with internal hydrogen to concentration of 140 wtppm in a high pressure environment at elevated temperature, a process called thermal precharging. While lower temperature in known to increase strength properties and reduced elongation at fracture, the presence of internal hydrogen increased both strength and elongation at fracture, but reduced ductility. Magnetic evaluation of the uniformly strained region of the test specimens suggest that hydrogen mitigates the strain-induced transformation to α’-martensite. Brittle fracture features and secondary cracking indicative of hydrogen embrittlement were observed on the fracture surfaces of hydrogen-precharged specimens, which is consistent with the loss of ductility.
Flutter of Rectangular Plate at Non-Zero Flow Yaw Angle
Authors: Abdukhakimov Farrukh , Vedeneev Vasily 
Published: October 2021

Abstract
Panel flutter is a phenomenon of self-exciting vibrations of skin panels of flight vehicles moving at high speeds. There are two types of panel flutter. The first one is the coupled-mode flutter, which is caused by the interaction of two panel eigenmodes. The second type is the single-mode flutter, in this case the coalescence of eigenfrequencies and a significant change in the oscillation mode shape does not take place. The stability of the infinite series of thin elastic rectangular plates simply supported along all edges is investigated in this study. The non-zero flow yaw angle with supersonic leading edge is considered. We use potential flow theory to derive expression for the unsteady aerodynamic pressure distribution over the oscillating plate. The plate motion equation, after the substitution of expression for unsteady aerodynamic pressure, with simply supported boundary conditions, is an integro-differential eigenvalue problem for finding complex eigenvalues. We use the Bubnov–Galerkin procedure for finding eigenvalues. Thus, the flutter criterion is the sign of imaginary part of eigenvalue. Flutter boundaries for the first eigenfrequencies were computed for non-zero yaw angles We show how the single-mode and coupled-mode flutter boundaries are changed with the change of the yaw angle.