bluuebunny/crossref_metadata_2025_split huggingface dataset:
Study on Alternative Bounding Approach for ASME Code Section XI Appendix L
Authors: Shim Do Jun , Tran Minh N. 
Published: November 2022

Abstract
Current Equivalent Single Crack (ESC) tables in ASME Code, Section XI, Nonmandatory Appendix L were developed using a probabilistic fracture mechanics (PFM) approach which included outdated K solutions and fatigue crack growth rates. Recent study demonstrated that the current ESC tables can be non-conservative when using the latest K solutions and fatigue crack growth rates. However, significant effort is needed to update and maintain the ESC tables. Hence, the ASME Code Committee Task Group on Appendix L has been discussing potential approaches to eliminate ESC from Appendix L. Present study was performed to develop an alternative bounding evaluation approach without using the ESC tables. Fatigue crack growth calculations for the ranges of pipe dimensions considered in Appendix L were performed. The objective was to identify options for potentially simplifying the Appendix L methodology. Two possible options were proposed. Option 1 was to use the allowable flaw depth from a 1:6 flaw and apply it to evaluate the fatigue crack growth of an initial 360° flaw. Option 2 was to use the allowable flaw depth of a 360° flaw and apply it to evaluate the fatigue crack growth of an initial 1:6 flaw. The time for a postulated initial flaw to reach the allowable flaw size for both options was calculated. The current study demonstrated that the flaw tolerance analysis using ESC is not bounded by either Option 1 or Option 2 when using the membrane-to-gradient cyclic stress ratio Δσm /Δσg = 0.0. However, when a more reasonable lower bound membrane-to-gradient cyclic stress ratio (i.e., Δσm /Δσg = 0.1) was used to determine the ESC, Option 1 results bounded most of the cases considered in the present study.
Ductile Damage Model Development and Validation of 316L Laser Powder Bed Fusion Steel Under Multiaxial Stress Conditions
Authors: Hales Theo , Rønneberg Tobias , Hooper Paul , Davies Catrin Mair 
Published: November 2022

Abstract
Laser powder bed fusion (LPBF) is an additive manufacture technique which builds components up in layers from a powder feedstock, using a scanning laser to selectively melt the powder into the required shape. The process of LPBF can often introduce defects into the structure of a part, since the powder may not fully melt and leave holes, or pores, in the sample. Excessive laser power may also cause the powder to vaporise and create pores. In whatever manner these pores are formed, they can significantly impact the properties of the finished component. Since pores and small defects already exist in LPBF components, the void growth and ductile fracture behaviour of LPBF components under multiaxial stress conditions needs to be characterised and predicted. In this work, notched bar tensile tests have been performed on samples with a range of notch acuities and hence multiaxial stress states. These tests have enabled ductile damage models to be calibrated and finite element (FE) simulations of the notched bar tests performed. The model was validated by comparison to the experimental results. The model agrees well with the results in many cases assessed in this work, but sometimes suffers from discrepancies and premature failure due to variability in material tensile properties, emphasising the need for sensitivity studies.
Analysis of Plastic Deformation of Pipes Due to Deflagration to Detonation Transition Using Static Equivalent Pressure
Authors: Müller Matthias , Bernhardi Otto-Ernst , Denecke Jens , Schildberg Hans-Peter , Schmidt Jürgen 
Published: November 2022

Abstract
Explosions of premixed gases with DDT, the transition from deflagration to detonation, are a risk in the process industry with potentially catastrophic consequences. Robust and simple design methods are required for industrial use. Such a simplified design method based on finite element analysis is proposed to model the dynamic behavior of pipes loaded by gas explosions of premixed gases including DDT.
First, it is reviewed how the pressure load of the gas explosion and the resulting material behavior has been modeled in previous publications. The analytical equations are then extended for describing the pressure load as a function of time and location by considering the leading compression wave as it affects the pressure load of the overdriven detonation. The extended analytical equations are parameterized using Chapman-Jouguet conditions and experimental results from publications for both static equivalent pressure and the location of the DDT. To describe the plastic material behavior at high strain rates, the well-known Johnson-Cook plasticity model is used. The material parameters of the model are derived from simple experiments, which are available in an industrial environment. The comparison of a finite element simulation with experimental data shows that the concept of equivalent static pressure can be extended to an FEM analysis, which in the future will allow the sizing of complete pipe systems including tees, bends and flanges while considering plastic deformation.
Influence of High-Pressure Hydrogen Gas and Pre-Charged Hydrogen on Fatigue Crack Initiation and Fatigue Life of 255 Super Duplex Stainless Steel
Authors: Kagay Brian , Ronevich Joseph , San Marchi Chris 
Published: November 2022

Abstract
High strength austenite-ferrite duplex stainless steels are a potential alternative to austenitic stainless steels for components in hydrogen gas storage systems. Since these components experience cyclic loading from frequent pressurization and depressurization, the effect of hydrogen on the fatigue behavior of duplex stainless steel must be understood. To determine the influence of hydrogen on fatigue crack initiation and fatigue life of a 255 super duplex stainless steel, circumferentially notched tensile (CNT) specimens were fatigue tested in the as-received condition in air, with pre-charged internal hydrogen in air, and in the as-received condition in high pressure hydrogen gas. The direct current potential difference (DCPD) method was used to detect crack initiation so that S-N curves could be produced for both (i) cycles to crack initiation and (ii) cycles to failure. An electropolished CNT specimen was also cycled in the as-received and hydrogen pre-charged conditions but interrupted just after crack initiation. The microstructural locations of small fatigue cracks were then identified with scanning electron microscopy and electron backscatter diffraction (EBSD). High pressure hydrogen gas and pre-charged hydrogen decreased the fatigue life of 255 duplex stainless steel by a nearly identical amount. The effects of hydrogen on fatigue crack initiation and fatigue life of 255 duplex stainless steel are discussed and compared to austenitic stainless steels.
Design Charts for an Integrated Creep-Fatigue Damage Evaluation Approach
Authors: Barua B. , Messner M. C. , Sham T.-L. 
Published: November 2022

Abstract
This paper discusses the development of design charts for creep-fatigue evaluation using an integrated elastic-perfectly plastic analysis (EPP) and Simplified Model Test (SMT) approach. The creep-fatigue damage evaluation approach in current ASME Section III, Division 5 rules requires separate evaluation of creep and fatigue damages and then considers the effect of creep-fatigue interaction with a creep-fatigue interaction diagram, also known as D-diagram. The EPP+SMT approach avoids the use of D-diagram by directly comparing the strain range determined from an EPP analysis with design charts, conceptually developed directly from creep-fatigue and SMT tests, to determine the creep-fatigue damage. The EPP+SMT approach provides much simpler creep-fatigue design evaluation process compared to current methods and is also expected to reduce the over-conservatism in current methods. Generating the EPP+SMT design charts requires extrapolating high strain range, short hold time test data to low strain range and long hold times, typically experienced by structural components in high temperature nuclear service. This work investigates several extrapolation approaches in the development of methodologies for constructing EPP+SMT design charts for Alloy 617 at temperatures between 800°C and 950°C. The design charts are validated using failure data from pressurized SMT tests and by comparing the EPP+SMT method with current design methods for representative high temperature nuclear reactor components.
Finite Element Analysis of Piping System Under Blast Load Due to Accidental Explosion
Authors: Dereli Ozer , Basu Sudipta , Ozbey Mehmet , Bhattacharyya Rudraprasad 
Published: November 2022

Abstract
This paper presents a methodology for nonlinear dynamic finite element analysis of piping system, which mainly consists of process piping, and pipe supports subjected to accidental blast loading. As opposed to an ASME B31.3 linear elastic static code check performed on Caesar II (Category 1) or a simplified single-degree-of-freedom (SDOF) approach (Category 2), a multi-degree-of-freedom (MDOF) approach is more realistic and less conservative for blast analysis of piping systems. Thus, the piping system is modeled as a multi-degree-of-freedom (MDOF) system to capture both the local and global responses. Furthermore, an in-house scripting tool was developed to automatically convert the piping stress analysis input files (in Caesar II) to blast analysis input files (in Abaqus). The scripting tool allows blast analysis of several hundreds of piping systems to be performed within a competitive project timeline. In the blast analysis model, blast load is applied as drag load on the piping system. In this study, geometric, material, and boundary condition nonlinearities are considered. The blast analysis is performed using commercial finite element software Abaqus/Explicit. The displacements and plastic strains at different locations of the piping system are evaluated and compared against a pre-established displacement limit and a plastic strain limit. Based on the analysis results, the number of additional pipe-supports which were required by linear elastic static or SDOF analysis approaches were significantly reduced along the piping systems.
Experimental Basis for the Extension of Elastic-Perfectly Plastic Strain Limits Evaluation Procedure of ASME Section III, Division 5 Code Case N-861 to Grade 91, Alloy 800H and 2.25Cr-1Mo
Authors: Wang Yanli , Hou Peijun , Sham Ting-Leung 
Published: November 2022

Abstract
The Elastic-Perfectly Plastic (EPP) based design method was qualified for ASME Section III, Division 5 Class A construction using Type 304 and 316 stainless steels and Alloy 617 via Code Case N-861 for Strain Limits evaluations. Because the isochronous stress-strain curves used in the EPP Strain Limits analysis were determined from standard creep testing on specimens without any prior cyclic loading history, experimental verification and analysis are required in order to extend the EPP Strain Limits analysis to the remaining three Class A materials, Grade 91, Alloy 800H and 2.25Cr-1Mo. In this study, specialized tests were designed and performed to evaluate the effects of cyclic deformation on the subsequent creep properties of these three Class A materials in the creep regime and the results are compared with standard creep tests. It is shown that reduction factors on the isochronous stress-strain curves are needed for Grade 91 to account for its cyclic softening effect. However, prior cyclic deformation has an insignificant effect on the minimum creep rates of Alloy 800H and 2.25Cr-1Mo, hence reduction factors are not required. The experimental results and analysis in this study provide the technical basis for the extension of Code Case N-861 to these three Class A materials.
Performing Under Pressure – Design Guidance for High-Pressure, High Cycle Piping System
Authors: Chae Jaehee 
Published: November 2022

Abstract
Plant owners are responsible for specifying piping fluid service categories and determining the applicability of ASME B31.3 Chapter IX for high-pressure piping. However, the code only defines the design for high-pressure fluid service piping, and many designers and engineers are not fully aware of the best design practices for low-stress and high-cycle applications.
Using innovative industry approaches and harmonic response analysis, dynamic stress levels of piping are calculated, and finite element analysis (FEA) used to calculate stress from the cycle range. This includes piping system design pressure at 10,200 psig with expectations of more than 1,000,000 stress cycles in a single day.
A thermal flexibility analysis of the piping system along with a fatigue analysis for the entire piping components within the system is performed in accordance with ASME BPV code Section VIII Division 3. The fatigue stress ranges of a properly designed vibrating piping system are typically well below the ASME BPV code limit.
High-pressure, unlisted piping fitting components such as reducers, tees, elbows and flanges, are also analyzed using the FEA and ASME BPV code design procedures.
This paper discusses the design process and deviations from the base code for piping design requirements as well as special techniques to consider for high-pressure and high-cycle piping.
Analysis of Mainframe Computer Structures Using Implicit and Explicit Finite Element Analysis
Authors: Notohardjono Budy , Canfield Shawn , Khambati Suraush , Ecker Richard 
Published: November 2022

Abstract
This paper discusses the finite element analysis (FEA) methods used to analyze the performance of a mainframe computer’s structural frame under a standard seismic loading such as that defined by Telcordia NEBS Zone 4. Specialists in the earthquake robustness area need to consider the basic mainframe structural information such as the total mass and the center of gravity in order to properly size and install tiedowns to prevent tiedown failure which can lead to hazardous tip-over events. To ensure successful operation through a seismic event, the total deflection of the top of the mainframe is a good indicator of ensuring the mainframe computer’s continuous operation.
As the mainframe computer’s total weight and the center of gravity varies depending on the specific customer configuration, this paper will examine the two extreme end cases: the lowest mass configuration with the highest location of the center of gravity and the highest mass configuration with the highest center of mass location. From a structural perspective, the higher the initial resonance frequencies, the more rigid the structure and the smaller the upper frame deflection will be. Thus, given a mainframe structure, the finite element analysis results will provide information on the weakest direction resonance frequency, which is in the narrow, side-to-side direction, along with the mainframe rack tiedown loads and maximum top frame deflection.
Given a mainframe structure’s finite element model and standard time domain seismic acceleration input at the base of the frame structure, the explicit finite element method will provide the performance of the structure namely the first resonance frequency, the maximum stresses at the rack structure, load at the tie down locations and the maximum top frame deflection. The explicit finite element analysis model can take into account the non-linear contact regions around weld areas and between adjacent sheet metal frame components as well as material non-linearities. The result of the FEA analysis of the several mainframe configurations will be compared to the results from actual seismic earthquake mainframe tests.
Evaluation of the Fracture Behavior of Cold-Worked Elbows With Prescribed Cracks
Authors: Kalyanam Sureshkumar , Pothana Sushma , Wilkowski Gery , Hioe Yunior , Orth Fabian , Brust Frederick , Gilbert Steven 
Published: November 2022

Abstract
Cold-working of elbows and other fittings results in higher strength of the material and has traditionally been considered to be beneficial for piping applications. Although it is known that cold-working leads to spatiotemporal variation in the grain size and the concomitant material property and fracture toughness variations they are not routinely investigated. Hence, this paper reports the findings from elbow fracture experiments conducted at 550°F and internal pressurized conditions (2,250 psi) on TP304 cold-worked elbows. The objectives for conducting the tests were to evaluate the effects of cold-working on the applicability of existing techniques such as an “Original” Net-Section-Collapse (NSC) and recently developed “Apparent NSC” equations for pipes with different inner diameter (ID) surface crack (SC) depths and lengths. This is to determine the failure moments and the plastic reduction factor (PRF) obtained to translate these to piping system evaluations. Preliminary comparisons of the experimental findings with the maximum stress predictions existing for straight pipes and elbow fracture prediction methods developed in the International Piping Integrity Research Group (IPIRG)-2 program were revisited, along with the verification of the applicability of the American Society of Mechanical Engineers (ASME) B2 stress indices and flaw acceptance criteria.
Crack Growth Modeling and Constraint Behavior Observations in Complex Crack Geometries
Authors: Kalyanam Sureshkumar , Hill Lance , Wilkowski Gery , Brust Frederick 
Published: November 2022

Abstract
The area of complex cracking in piping components and its effects on the fracture behavior and leak-before-beak evaluations has been highly researched. Several researchers have conducted experiments to quantify the behavior through complex cracked piping experiments starting from the 1980s and also more recently in dissimilar metal welds (DMWs). The area has also seen several contributions on the modeling aspects to characterize the crack initiation as well as the ductile crack growth behavior. In this work, the crack growth in complex-crack geometries is revisited through a novel laboratory specimen model, developed by modifying a Single-Edge Notch Tension SEN(T) specimen that is routinely used to obtain the fracture toughness values for both crack initiation as well as crack growth/tearing behavior. Details on the cell size used in the finite element analysis (FEA), and the effects on the predictability of the experimental observations are highlighted. The effects of constraint based on the relative levels of complex-cracking (aspect ratios) are discussed. While the results are precursors to the understanding of the correlations of constraints and fracture for these complex-cracked geometries, they provide guidelines for path forward towards development of methodologies to treat these when making reliable comparisons between material fracture resistance and crack driving forces that are routinely employed in fracture-based leak-before-break assessments for piping and piping components.
Fatigue-Life Prediction and Design for Uncracked and Cracked Components: Deterministic, A- and B-Basis Probabilistic, and Reliability Target Approaches
Authors: Fong Jeffrey T. , Marcal Pedro V. , Freiman Stephen W. , Heckert N. Alan , Filliben James J. 
Published: November 2022

Abstract
Based on a recently developed multi-scale fatigue-fracture-NDE reliability model for uncracked and cracked pipes (see Fong-Marcal-Rainsberger-Heckert-Filliben-Doctor-Finney, PVP2021-62169), we apply the same modeling technique to a comparative study of three approaches to fatigue-life prediction and design: Approach (1). Deterministic. Approach (2). Probabilistic using the A- and B-basis design allowables. Approach (3). Reliability Target using the concept of a co-reliability or an upper bound of failure probability as a tool for damage assessment and control. To illustrate the comparison of the three approaches to both uncracked and cracked components, we present numerical examples for generic components of three engineering materials at room temperatures, namely, (a) AISI 4340 steel for piping, (b) 2024-T4 aluminum for aircraft structures, and (c) BK-7 borosilicate crown glass for aircraft windows. In particular, for cracked components inspected by NDE personnel with varying probability of detection (POD) qualifications, we find both Approach (1) and Approach (2) inadequate as a guide for maintenance decision-making and compliance with the ASME Boiler and Pressure Vessel Section XI Division 2 Reliability and Integrity Management (RIM) Code. Significance and limitations of the methodology for Approach (3) based on the concepts of co-reliability and reliability target are presented and discussed. Some concluding remarks and future work are included at the end of this paper.
Case History of Hydrotreater Prefeed Heater Fire Recovery
Authors: Penso Jorge , Park Neil , Dalal Mitul , Hosack Alexandra 
Published: November 2022

Abstract
A prefeed heater in a hydrotreater unit experienced a fire while being prepared for shutdown during a turnaround. The prefeed hydrotreater heater was a mixed operation heater that typically operated in mixed mode with hydrogen and hydrocarbon bitumen, but at the time of the incident was operating in hydrogen only mode in order to hot hydrogen strip the hydrotreater.
The heater had been in operation since 2011 and had a design fluid temperature of 425 °C (797 °F), a tube metal temperature of 570 °C (1058 °F) and design pressure of 16,800 kPag (2437 Psig). The normal operating pressure was 15,000 kPag (2176 Psig). The radiant and convection tubes were fabricated from Type 316Nb stainless steel (UNS31640). There was a tube rupture in the radiant section that caused the fire and the subsequent failure investigation established that the temperature in the radiant section at the rupture location had reached in excess of 850 °C (1562 °F) for over a 15-minute period prior to rupturing. The following paper outlines the failure analysis and root causes which caused the incident, while detailing the recovery and construction of the heater, including the fitness-for-service methods and inspections conducted. The heater was partially rebuilt with the convection section tube material being recovered and the radiant section being rebuilt in a different metallurgy.
Developing a Test Protocol to Determine Packing Performance in a Soot Blower
Authors: Henriques Isadora R. , Meira Igor , Girão Carlos D. 
Published: November 2022

Abstract
Soot deposit accumulation on heat transfer tubes and surfaces in recovery boilers reduces thermal performance, compromising thus the efficiency and life of the equipment. A soot blower is employed to remove these by-products to maintain boilers within design conditions. This specialized device has a seal between its tubes to maintain fluid pressure to clean the heating pipes and inside surface. Nevertheless, sealing can be a challenge due to its large displacement amplitude, the reciprocating movement, and the sudden change of temperature and pressure. Many different solutions are available in the market that offers viable sealing methods, but there is no test method to classify them. This work proposes a soot blower test protocol to evaluate the sealing solutions available. Comparative results for the different seal types are presented.