bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of the Bending Stiffness of Bolted Flange Joints on the Dynamics of Aero-Engine Rotors
Authors: Zhu Linbo , Pan Hu , Yang Yilong , Bouzid Abdel-Hakim , Hong Jun 
Published: November 2022

Abstract
Bolted flange joints are used to connect adjacent disks and drums in aero-engine rotors. The flange mating contact surfaces usually move relative to each other and deform when they are subjected to numerous combinations of loads during normal operation. Consequently, the local bending stiffness of the bolted flange joint is altered considerably affecting the overall rotor stiffness and therefore the rotor dynamics.
This paper presents a study on the effect of the bending stiffness of bolted flange joints on the dynamic characteristics of an aero-engine rotor. A method to calculate the bending stiffness is proposed using an equivalent model based on an axial spring and bending beam stiffnesses. The relationship of the structure geometry, loading and assembly conditions of the bolted flange joints, and the bending stiffness loss are obtained. Furthermore, a dynamic model of an aero-engine high-pressure compressor rotor is developed using the transfer matrix method that incorporates the bending stiffness effect of the bolted flange joint. Based on this model, the influence of bending stiffness on the natural frequency and the steady-state response is discussed. The results show that the stiffness loss of bolted flange joint has a significant impact on the rotor dynamics. The structure geometry, loading, and assembly conditions can be used to control the dynamic response of aero-engine rotors.
Investigations on Multi-Stage Tests and Transient Endurance Limit Behavior Under Low-, High- and Very High Cycle Fatigue Loads
Authors: Schopf T. , Weihe S. , Rudolph J. 
Published: November 2022

Abstract
The fatigue analyses included in nuclear rules of KTA [1]–[2] and ASME [3] are based on defined loads (specified or measured loads and frequencies). It is assumed that highly cyclic loadings or resonance vibrations are avoided by appropriate design. Often these loads are recorded by measurements during commissioning or during operation. In particular, in pressure vessel and reactor internals such vibrational excitations cannot be excluded, so that fatigue loadings in the HCF regime and even in the VHCF regime can occur. Since these kinds of loading situations also appear in combination with fatigue loadings in the LCF regime, load collectives are to be considered, as they are not explicitly taken into account in the current analysis of the nuclear regulations. Furthermore, no generally validated method, especially a consolidated damage accumulation model is available. Furthermore, design fatigue curves for austenitic steels in the applicable international design codes were extended by extrapolation from originally 106 up to 1011 load cycles [1]–[3]. However, the existing database for load cycles equal to or above 107 is still insufficient. Therefore, international efforts are currently ongoing in order to expand the database through international co-operations and compile a safe high cycle fatigue (HCF) database [4]. This is particularly important in combination with the influence of the cooling medium and its consideration according to established international standards as the database of the Argonne National Laboratory ANL [5] for fatigue behavior under medium conditions. For the range from HCF to VHCF and for their combination with LCF loads (collective effect) and the currently discussed limit values above which the cooling medium has an effective influence on the fatigue strength are not sufficiently consolidated. These aspects gain in importance particularly in the long-term operation context. A recently finished cooperative research project aims at contributing to closing these mentioned gaps by generation of a data and assessment basis for the fatigue behavior of welded austenitic stainless steels at high numbers of load cycles [6].
The following topics will be discussed in detail in the paper:
• Fatigue behavior at variable amplitude loading (combination of LCF / HCF and LCF / VHCF)
• Development of a fatigue assessment methodology under consideration of the transient endurance limit and damage accumulation effects including assessment and adaptation of appropriate fatigue damage parameters
Stud Bolt Thread Engagement: A Fitness for Service Approach
Authors: Cranford Colton M. 
Published: November 2022

Abstract
In the pressure equipment industry, codes of construction stipulate that fastener assemblies shall exhibit thread engagement through the full depth of the nut. In many older facilities and in locations with poor quality control, assemblies may be found on in-service equipment which do not have full thread engagement and do not meet the requirements of the code of construction. This is often found during the routine visual inspection of equipment and is flagged as a construction code deficiency requiring attention. Current post construction code guidance on fastener assemblies is ambiguous on how to handle fasteners with less-than-full thread engagement exceeding one thread of shortfall. The perceived risk of such a lack of thread engagement may lead maintenance organizations to perform costly and high-risk remediation activities, such as in-service “clamping” or “single stud replacement,” also known as “hot-bolting.” However, in many situations, fastener assembly strength can be proven to be sufficient for a given joint through analytical evaluation. Using a combination of innovative and existing thread strength and flanged joint considerations, the minimum required length of engagement, and, thus, the maximum allowable lack of engagement, can be safely determined for most fasteners on flange connections. This paper reviews some of the most important fastener strength considerations to propose a post-construction evaluation technique to determine the fitness for service of less-than-fully engaged fastener assemblies.
Evaluation of Welding Techniques for Stainless Steels Piping Without Use of Backing Gas
Authors: Sanagavaram Chakradhar , Chiluvuri Sivakumar , Penso Jorge 
Published: November 2022

Abstract
Austenitic Stainless steel SS304L and SS316L are extensively used as piping material for cryogenic and corrosive services in an LNG plant. GTAW welding process is a widely used welding process for joining stainless steel pipe work in pipe fabrication yards. For pipe welding, the GTAW process uses inert backing gas or purge gas (e.g. Argon) to prevent oxidation of root pass in order to achieve the weld quality. Welding large diameter stainless steel pipes using GTAW with inert gas introduces significant risk of asphyxiation when a welder enters the pipe that has resulted in fatalities based on industry references. A large LNG project mandated that only welding techniques without backing gas were permitted for joining stainless steel pipes of size &gt; 24”. The project team evaluated four alternative welding techniques with no backing gas and Advanced or Modified Short-arc GMAW was selected. Initial scope covered cryogenic services and later extended to include corrosive / wet (aqueous) services.
This paper discusses the approach the project chose including the literature evaluation from the industry experiences, non-backing gas welding qualification and test protocols, curating technical specification, PQR testing and developing WPS’s and welder training and qualification program at the module fabrication yards. The paper also presents the knowledge, experiences gained, and challenges faced in implementing the non-backing gas welding for joining large size stainless steel pipe work in an extensive scale spanning multiple piping module fabrication yards globally.
Overview of Suitable Methodologies for Threshold Stress Determination by Small Punch in Aggressive Environments
Authors: Andrea Calvo Laura , Arroyo Martinez Borja , Álvarez Laso José Alberto , Gutiérrez-Solana Federico , Cicero González Sergio , Lacalle Calderón Roberto 
Published: November 2022

Abstract
The Small Punch Test is a recently standardized technique successfully employed for estimating the tensile, creep and fracture properties of metallic materials, and is considered as one of the most suitable options for evaluating mechanical properties when materials are in shortage. Several advances have been made in order to apply this methodology for mechanical characterizations in aggressive environments. The first tests were carried out pre-embrittling the samples in environment and then testing them in air. Subsequent methodologies proposed tests in environment after pre-embrittling the samples in order not to lose part of the embrittling capacity while testing; in these scenarios the punch rate has an enormous influence on environmental characterizations. The most recent works propose to implement in the Small Punch Test the step loading methodology collected in ASTM F1624 standard, which solves these problems by applying steps at a constant load which gradually increases until the sample fails. In this work, guidelines for the application of Small Punch Tests to determine the threshold load in aggressive environment are given, based on tests results under hydrogen embrittlement scenarios. A range of punch rates for constant punch displacement is provided, together with the suitable step times when applying the step loading technique, and a correlation to estimate the threshold stress based on Small Punch samples tested with this novel technique.
Verification and Applicability of a Simplified Method for Analyzing Blast Overpressure in Vertical Pressure Vessels
Authors: Hundl Jacob , Millet Barry , Mosher Bryan , Kirkpatrick Kenneth 
Published: November 2022

Abstract
A simplified method for analyzing pressure vessel response to blast overpressure incidents was developed in a previous study that demonstrated the ability to apply, evaluate and interpret the results of an overpressure incident on vertical pressure vessels without the use of advanced FEA software. The previous study was primarily focused on the development of the simplified method from existing literature and the step-by-step implementation of the method in an example case. The method itself was only applied to one example case and compared to a control case. This paper will verify the simplified method and determine its applicability by evaluating the response of several different vessels to different overpressure values and comparing the results to control cases performed using the CONWEP model in ABAQUS. The sampling of vessels will be determined by using common vessel diameters with different diameter to length ratios. The simplified method developed in the previous study will also be further refined by the application of Newmark’s Method, which allows for the evaluation of the dynamic response of a system to a time-history loading. Newmark’s Method is an average acceleration scheme that is primarily used in structural analysis to measure seismic response. The results from the analysis, along with a comparison between the data from the simplified method and the control case, will be discussed.
Fatigue and Fracture of Pipeline Steels in High-Pressure Hydrogen Gas
Authors: San Marchi Chris , Ronevich Joseph A. 
Published: November 2022

Abstract
Decarbonizing natural gas networks is a challenging enterprise. Replacing natural gas with renewable hydrogen is one option under global consideration to decarbonize heating, power and residential uses of natural gas. Hydrogen is known to degrade fatigue and fracture properties of structural steels, including pipeline steels. In this study, we describe environmental testing strategies aimed at generating baseline fatigue and fracture trends with efficient use of testing resources. For example, by controlling the stress intensity factor (K) in both K-increasing and K-decreasing modes, fatigue crack growth can be measured for multiple load ratios with a single specimen. Additionally, tests can be designed such that fracture tests can be performed at the conclusion of the fatigue crack growth test, further reducing the resources needed to evaluate the fracture mechanics parameters utilized in design. These testing strategies are employed to establish the fatigue crack growth behavior and fracture resistance of API grade steels in gaseous hydrogen environments. In particular, we explore the effects of load ratio and hydrogen partial pressure on the baseline fatigue and fracture trends of line pipe steels in gaseous hydrogen. These data are then used to test the applicability of a simple, universal fatigue crack growth model that accounts for both load ratio and hydrogen partial pressure. The appropriateness of this model for use as an upper bound fatigue crack growth is discussed.
Comparison of Stresses in Flexible Shell Element Expansion Joint of a Heat Exchanger for Code Application When Made of Multiple Flexible Shell Element
Authors: Mathkar Ameya , Gopalakrishnan Shyam , Pathre Sujay S. 
Published: November 2022

Abstract
To reduce shell and tube longitudinal stresses and tube-to-tubesheet joint stresses in a fixed tubesheet heat exchanger, expansion joints are provided. In addition to providing pressure integrity, the expansion joints provide flexibility for thermal expansion. ASME Sec. VIII Div.1 provides the methodology for evaluation of stresses in the expansion joint in both corroded and non-corroded condition for loading conditions under mechanical loads only, thermally induced displacements only or both. However, when it comes to the design rules, the ASME Sec. VIII Div. 1 leaves it to the user to perform the design calculations by a method (i.e., stress analysis) that can be shown to be appropriate for expansion joints.
For thick bellow expansion joints, it is a common practice for the industry to adopt the methodology described in TEMA for performing the design calculations. The latest TEMA (10th Edition) in comparison to the previous edition has modified the methodology for applying the loading conditions for spring rate and stress determinations.
It is a common practice for the industry to model the half-length symmetry flexible shell element in the Finite Element Analysis for determination of stresses and spring rate. This approach holds good when the heat exchanger comprises only one flexible shell element. However, in the industry owing to complex application requirements at times, it is a requirement to have multiple identical flexible shell elements or multiple non-identical flexible shell elements. The TEMA standard provides rules for FEA when multiple flexible shell elements are provided in an expansion joint. The methodology described in TEMA has certain conditions of applicability and holds good provided those criteria are met. However, when the stipulated criteria are not met, the TEMA standard leaves it to the discretion of the designer to approximately model the geometry for spring rate and stress determination.
The work reported in this paper is an attempt to evaluate the spring rate and determine the stresses for multiple flexible shell elements by means of FEA and verification of Code compliance and review of literature.
Numerical Investigation of Ductile Crack Propagation of Circumferentially Cracked Pipes Subjected to Multiaxial Loading at Room and Low Temperatures
Authors: Li Yuhao , Paredes Marcelo 
Published: November 2022

Abstract
Failure in pipes containing an initial crack under multi-axial loading condition is of common occurrence in industry and engineering applications. Current fitness-for-service codes and design standards cover partially part of this complex type of failure mode where the stress states may change abruptly from one state to another due to the combinatory nature of the applied loads. However, the torsional moment is mostly disregarded in the analysis for being apparently negligible in front of the bending moment and axial force, whose combined effects on crack-tip stress-strain fields have been very well investigated in the past. Based on recent research efforts to understand its effect, it has found that torsion in combination with axial force and bending moment, in fact, increases structural strength and delay fracture propagation, whose intensity varies depending on the crack configurations. Inspired by previous observations, this work takes a step forward in understanding effects of combined torsion with bending and axial force under harsh environments such as low temperature levels. A comprehensive numerical investigation is carried out using a newly developed constitutive model to describe failure at low temperatures on multi-axially loaded cracked pipes made of 316L stainless steel. Kinetic phase transformation and temperature dependent fracture criterion are implemented to accurately capture mechanical response at different temperature levels. Even though, experimental observations of these simulations were not available, their outcomes were quite consistent with some already published results performed on similar materials and loading conditions.
Compatibility of Medium Density Polyethylene (MDPE) for Distribution of Gaseous Hydrogen
Authors: Shrestha Rakish , Ronevich Joseph A. , Fring Lisa , Simmons Kevin , Meeks Noah D. , Lowe Zachary E. , Harris Timothy J. , San Marchi Chris 
Published: November 2022

Abstract
Numerous projects are looking into distributing blends of natural gas and different amounts of gaseous hydrogen through the existing natural gas distribution system, which is widely composed of medium density polyethylene (MDPE) line pipes. The mechanical behavior of MDPE with hydrogen is not well understood; therefore, the effect of gaseous H2 on the mechanical properties of MDPE needs to be examined. In the current study, we investigate the effects of gaseous H2 on fatigue life and fracture resistance of MDPE in the presence of 3.4 MPa gaseous H2. Fatigue life tests were also conducted at a pressure of 21 MPa to investigate the effect of gas pressure on the fatigue behavior of MDPE. Results showed that the presence of gaseous H2 did not degrade the fatigue life nor the fracture resistance of MDPE. Additionally, based on the value of fracture resistance calculated, a failure assessment diagram was constructed to determine the applicability of using MDPE pipeline for distribution of gaseous H2. Even in the presence of a large internal crack, the failure assessment evaluation indicated that the MDPE pipes lie within the safe region under typical service conditions of natural gas distribution pipeline system.
Effect of Trapped Fluid on Expandable Liner Hanger Performance in Geothermal Applications
Authors: Yin Shengjun , Zhong Allan , Abir M. D. , Gharesi Abdolreza 
Published: November 2022

Abstract
A metal-to-metal sealing expandable liner hanger (ELH) was designed for high pressure/high temperature (HPHT) applications [1]. It has been proven to be very robust for geothermal applications in deep well simulator testing, with temperatures up to 575°F. A potential scenario when using this ELH for geothermal applications is that fluid could be trapped between the expanded hanger and casing ID. The trapped fluid can induce a pressure change from a significant temperature rise because fluids typically have much higher thermal expansion coefficients than metals. When the temperature rises, the trapped fluid can generate significant pressure between the hanger and the casing. On the other hand, the volume change on the cavities can reduce the trapped pressure if the temperature change is not large enough and may help to increase anchoring capacity. The full fluid-structural interaction needs to be considered to accurately evaluate the effect of trapped fluid on expandable liner hanger performance.
This paper illustrates how a surfaced-based fluid cavity finite element model can be utilized to simulate fluid-structural interaction between the structure and the trapped fluid [2, 3]. The model accounts for the coupling between the deformation of the surrounding structure and the pressure from the trapped fluid acting on the structure. This methodology was applied to investigate the effects of trapped fluid on the ELH performance when subjected to high pressure/high temperature applications.
With a specific well condition in consideration, it was observed that: 1) the pocket (cavity) pressure after expansion was lower than the hydrostatic pressure, as per design intention; 2) the net effect was that the hydrostatic pressure squeezed the hanger which improved the ELH hang weight capacity.
In the extreme well conditions where the trapped fluid pressure may reduce the hanger anchor capacity, a novel design concept was developed to mitigate trapped fluid pressure effect.
Nickel Cladded Structural Components for Advanced Reactors
Authors: Barua B. , Messner M. C. , Sham T.-L. 
Published: November 2022

Abstract
The aggressive corrosive environment along with higher operating temperature in molten salt reactors present significant challenges to existing structural materials that have been qualified in the ASME Section III, Division 5 Code for high temperature cyclic service. Corrosion resistant claddings offer an attractive near-term solution to mitigate corrosion concerns and enable the use of ASME Code qualified materials for advanced reactor structural components. Nickel provides good corrosion resistance to molten salts as well as good thermal and mechanical compatibility with existing ASME Code qualified materials, and therefore can be used as a cladding material for structural components in molten salt reactors. However, there are currently no ASME design rules for cladded components to guard against creep-fatigue failure and ratcheting strain accumulation under high temperature cyclic service. Recently, we have developed new design rules for components cladded with creep-compliant materials (e.g. nickel clad on 316H base metal) for high temperature cyclic service. These design rules require design parameters that can be established through relatively short-term testing for the clad material. This work shows how the design parameters for nickel are developed using fatigue and creep-fatigue test data. Finally, the paper walks through a sample problem detailing the application of the design rules to 316H components cladded with nickel.
Numerical Approaches for Bolt Interactions in Flange Gasket Assemblies
Authors: de la Roca Leonardo , Meira Igor , Girão Carlos D. , Carlos Veiga José 
Published: November 2022

Abstract
In most industrial plants, the maintenance of the piping system is a crucial part of the site’s health and integrity, as leakage can often lead to costly losses and even disastrous accidents with the loss of life. An incorrect assembly of a bolted flange joint will most likely form a leak path in the sealing surface and lead to joint failure. Standards such as the ASME PCC-1 Guidelines for Pressure Boundary Bolted Flange Joint Assembly, have the purpose of guiding towards safer procedures of gasket installation in bolted flange connections, where specific gasket assembly methods regarding recommended fastening torque and bolt sequence are described in detail. However, to this day, said guidelines are not strictly followed. The lack of training concerning the recommended methods leads to unqualified flanged joint assemblers and hence the most common cause of gasket failure, which is an improper installation. Therefore, there is a need to produce instructional tools, physical in nature or not, that help raise awareness to the recommended, standardized, gasket installation methods and good practices in bolted flanged joint assemblies, aiming to reduce the volume of industrial plants’ leakage caused by improper installation, preventing further health and environmental problems. The present work describes a set of mathematical methods designed for flange assembly training simulations, intended to be used as an educational tool to enhance the abilities and knowledge of assemblers. The work includes methods of calculating elastic interactions between bolts and other common phenomena characteristics of flange tightening.