bluuebunny/crossref_metadata_2025_split huggingface dataset:
Predicting Crack Velocity and Fracture Arrest Pressure From Simulations of Dynamic Pipe Rupture
Authors: Williams Bruce W. , Xu Su , Tyson William R. 
Published: November 2019

Abstract
During a gas pipeline rupture event, the crack propagation velocity can exceed 300 m/s and the crack can run for several hundreds of metres before arresting. The current model to predict arrest pressure is the Battelle Two Curve Method (BTCM) using the Charpy V-notch energy to characterize propagation toughness. It has been shown that this model can give non-conservative predictions for high-strength pipe steels. Hence, the Crack Tip Opening Angle (CTOA) has been introduced as a promising parameter to describe crack propagation. The objective of the current work was to study the crack propagation process in pipe by Finite Element Analysis (FEA) techniques to gain a better understanding of crack driving force and factors influencing CTOA. Implicit FEM simulations of dynamic crack propagation in pipes with diameters ranging from 355 mm to 1219 mm with a wall thickness of about 19 mm were performed using material properties representative of either X65 or X80 pipeline steel. The specification of a critical CTOA and the nodal release algorithm in the software WARP3D were employed to propagate the crack up to about two metres in the simulations. For a given critical CTOA, pipe diameter, and pipe thickness a set of simulations was performed where the initial applied gas pressure varied from as low as 4 MPa up to 60 MPa (which corresponds to about 80% of the yield strength of the material). The CTOA values used in the simulations ranged from 5° to 20° and corresponded to CTOA measurements obtained in concurrent work from Drop Weight Tear Tests performed on pipe steels. To accurately predict crack velocity, it was important to apply a flap loading profile near the crack front representative of the gas pressure response during pipe rupture. Comparison of the crack propagation response was carried out between a constant pressure profile just behind the crack front and a pressure profile that varied with circumference a round the pipe. The influence of soil pressure on the flap loading response was also considered in the models. The predicted pressure versus crack velocity profiles and the arrest pressure can then be subsequently used to predict the arrest length for a given CTOA.
Strain Sensing for Compact Heat Exchanger Defect Detection
Authors: Hu Xiaochen , Fan Zhaoyan , Paul Brian 
Published: November 2019

Abstract
The development of Compact Heat Exchangers (CHE) improves heat transfer efficiency with surface-to-volume ratios approaching 2500 m2/m3. In the applications such nuclear plants, CHE need to work for years in a harsh environment of high temperature up to 800 °C and high pressure up to 20 MPa. Any structural failure, i.e. cracks due to material fatigue or residual stress concentration in the CHEs, may result in safety problems and tremendous economy losses. Compared to the conventional heat exchangers, the non-destructive testing for CHE is challenging because the deformation of micrometer sized channels is hard to detect by the conventional means such as strain gauges or ultrasonic sensors. This paper presents a novel approach to detect the presence of cracks using fiber strain sensors embedded in the compact heat exchangers. The fiber sensors are proposed to install the heat exchanger with the microchannel plate stacks in the heat exchanger, measuring the strain distribution in the structure during the operation. Numerical and analytical models of CHE with and without cracks are built to learn crack size influence on strain variation. Sensors’ sensitivity to crack positions was calculated through simulation. A defect retrieval algorithm based on Tikhonov regularization is presented to achieve crack detection according to sensors’ outputs. A sample CHE section with 5x5 channels are simulated to quantitatively test the accuracy and validity of the proposed method.
Brittle Fracture Assessments on Piping Systems: MSOT Curves
Authors: Chakraborty Ishita , Subramanian Kannan , Penso Jorge 
Published: November 2019

Abstract
Brittle fracture assessments (BFAs) of pressure vessels based on API 579-1/ASME FFS-1, Section 3 procedures are frequently easier and more straightforward to implement in comparison to the BFAs on piping systems. Specifically, the development of the MSOT curves. This is due to the complexities involved in the piping systems due to the branch piping interactions, end conditions of piping systems such as nozzle flexibilities at the pressure vessel connections, temperature changes in the length of piping especially when the piping is significantly long as seen in flare header piping systems. MSOT curves that are alternatively used for MAT curves provide a better picture to the plant personnel in understanding the safe operating envelope. Development of MSOT curves is an iterative process and therefore involves significant number of piping stress analyses during their development. In this paper, an approach to develop the MSOT curves is discussed with two case studies that are of relevance to olefin plants.
Screening Technique of Hydrogen Embrittlement Sensitivity in Austenitic Stainless Steels Using In-Situ Small Punch Test Method
Authors: Shin Hyung-Seop , Bae Kyung-Oh , Kim Hyuckmin , Baek Un-Bong , Nahm Seung-Hoon 
Published: November 2019

Abstract
In this study, a simple screening technique using an in-situ small-punch (SP) test and based on the hydrogen embrittlement (HE) sensitivity of austenitic stainless steels was developed for use in hydrogen energy facilities. To investigate the HE behaviors of metallic materials, the in-situ SP tests were carried out under high-pressure hydrogen gas environments. The reductions of thickness at the fractured parts of the specimen were measured. The relative reductions of thickness (RRT) were determined after conducting SP tests in both hydrogen and inert gas environments. Similar to the relative reduction of area (RRA) obtained using the slow strain-rate tensile test, RRT obtained using the in-situ SP test is a quantitative measure of the influence of the HE behaviors. The influence of punch velocity on HE sensitivity was examined. The HE behaviors of austenitic steels were evaluated qualitatively and quantitatively. The high-Mn steels were also evaluated because they are candidates for storage and transportation of hydrogen gas. A screening technique for determining the practical environmental conditions at the point of use could be established by confirming the effectiveness of the influencing factor, RRT, using this in-situ SP test method.
Assessment of Free Standing Body in Dry and Submerged Condition and Under Seismic Loading
Authors: Rovagnati Beniamino , Hoang Phuong H. 
Published: November 2019

Abstract
A free standing, slender body may experience rocking motion followed by overturning when it is subject to strong seismic motions. When the free body is submerged in water, it will also be subject to lateral forces acting along the side of the free body as a result of water sloshing. This highly non-linear situation is of particular interest to engineers in the nuclear industry in need to assess the stability of transfer casks containing spent fuel and submerged in a confined pit or pool. In this work, a three-dimensional finite element dynamic transient model of a free standing cask is developed and analyzed using ANSYS. Both dry and submerged conditions are considered. Cask to floor friction, buoyancy force, and sloshing are accounted for in the assessment. The model is validated against well-accepted contributions on sloshing and rocking provided by G.W. Housner.
Blast Attenuation in Tunnels or Pipes With Turns
Authors: Geng Jihui , Thomas Kelly 
Published: November 2019

Abstract
Shock wave attenuation in a straight tunnel (or pipe) can be evaluated using existing methodologies. Shock attenuation is enhanced when there are right-angle turns along the length of the tunnel over which the shock is transmitted. A repeated set of such turns is generally defined as a blast trap. Little guidance is available in the open literature regarding the blast attenuation enhancement due to a right-angle turn or a blast trap in a tunnel. This paper presents guidance for shock wave attenuation as a function of the number of right-angle turns and blast wave parameters (i.e., peak pressure and duration). Characteristic parameters are utilized in order to define shock wave properties and tunnel dimensions. The shock attenuation due to up to four consecutive right-angle turns is evaluated. The purpose of this work is to provide a database of the shock attenuation within a tunnel due to multiple right-angle turns for use in designing tunnel structural components and evaluating the response of such components to postulated transmitted shock loads.
Production Impact Testing Exemption for Round-Seams (Category B Welds) of Welded Pressure Vessel in ASME-Section-VIII Division-1
Authors: Kilambi Sreelatha 
Published: November 2019

Abstract
In lean manufacturing environments for efficient schedule, most process equipment manufacturers procure shells. When impact-tested shells are required, long-seam (Category-A) weld-procedures differ from round-seam (Category B) weld-procedures, thereby initiating UG-84(i) of ASME Section VIII Division 1. UG-84(i) states that when weld procedures for Category B welds are different, weld production impact test is required.
This paper evaluates possible production impact test exemption for Category B welds based on stress ratio of each category of weld. While long seams require impact testing at lower thickness range, fully radio-graphed round-seams for Curve-D materials may be exempt from production impact testing with weld procedure controls from UCS-67(a)(3) and impact-tested weld metal at desired minimum design metal temperature. Not including temperature shift below impact test temperature due to dynamic impact testing provides added safety and conservatism to UCS66 rules in the code. Change in rules will provide manufacturers significant relief from production impact tests for Category-B welds that are under-stressed with safety factors currently in Figure UCS 66.1.
Nondestructive Evaluation of Metal Strength, Toughness, and Ductility Through Frictional Sliding
Authors: Palkovic Steven , Patel Parth , Safari Soheil , Bellemare Simon C. 
Published: November 2019

Abstract
Traditional assessment of mechanical properties requires the removal of a standardized specimen for destructive laboratory testing. A nondestructive in-situ method is a cost-effective and efficient solution for applications where sample cutouts are not feasible. This work describes developments in contact mechanics that use frictional sliding to evaluate the material strength and toughness of steel pressure vessels and pipelines.
Hardness, Strength, and Ductility (HSD) testing is a portable implementation of frictional sliding that provides a tensile stress-strain curve for assessment of the yield, ultimate tensile strength (UTS), and strain hardening exponent for power-law hardening metals. HSD testing incorporates four styluses of different geometry that generate grooves on the surface of a material as they travel. The measured geometry of these grooves along with the normal reaction forces on the stylus are correlated to representative tensile stress-strain values through finite element analysis (FEA) simulations. These principles have been extended to account for nonlinear strength behavior through the thickness of seam-welded steel pipes by using a combination of the HSD surface measurement, microstructure grain size, and chemistry. Frictional sliding tests are also used to assess material variation across a welded seam to identify different welding processes and the effectiveness of post-weld-heat-treatments (PWHT).
A second implementation of frictional sliding is Nondestructive Toughness Testing (NDTT), which provides an NDE solution for measuring fracture toughness by using a wedge-shaped stylus with an internal stretch passage to generate a Mode I tensile loading condition on the surface of a sample. The test produces a raised fractured surface whose height provides an indication of the materials ability to stretch near a propagating crack and is correlated to the crack-tip-opening-displacement (CTOD) measured from traditional laboratory toughness testing. Experiments on pipeline steel indicate that NDTT can provide an index of fracture toughness to benchmark materials tested under similar conditions. Implementation of these new instruments to gather data for integrity management programs, fitness for service assessments, and quality control of new manufacturing will help to reduce risk and uncertainty in structural applications.
PVB Blast Load Enhancement due to Mach Stem
Authors: Lowry Will , Geng Jihui 
Published: November 2019

Abstract
A pressure vessel burst (PVB) is an explosion scenario commonly encountered at chemical processing and petroleum refining facilities. Existing methodologies are available to predict the blast loads resulting from a spherical or cylindrical PVB source, with the PVB source either at grade or at an elevation. In the case of an elevated PVB source, the resulting blast wave will reflect from the ground at an angle. This ground level reflection will result in the formation of a Mach stem at certain angles between the incident blast wave and ground, with the required angles dependent on the blast wave overpressure. The triple point associated with the Mach stem moves upwards as the Mach stem progresses forwards, which can create a region of high blast pressure. This paper focuses on the investigation of a methodology that can be used to determine the high-pressure region generated by the Mach stem, along with the associated blast pressure, as a function of the PVB source elevation and incident blast pressure.
Master Curve Fracture Toughness Characterization of Eurofer97 Steel Variants Using Miniature Multi-Notch Bend Bar Specimens for Fusion Applications
Authors: Chen Xiang , Sokolov Mikhail A. , Bhattacharya Arunodaya , Clowers Logan N. , Graening Tim , Katoh Yutai , Rieth Michael 
Published: November 2019

Abstract
In this study, we performed fracture toughness testing of ten Eurofer97 steel variants using precracked miniature multi-notch bend bar (M4CVN) specimens based on the Master Curve method in the ASTM E1921 standard. Additional Vickers microhardness and room temperature tensile testing complemented the fracture toughness testing. Compared with standard Eurofer97, the ten variants didn’t show a comprehensive improvement of mechanical properties. The Master Curve method was found to yield a reasonable prediction of fracture toughness results obtained from M4CVN specimens with most valid fracture toughness data within the 2% and 98% tolerance boundaries of the Master Curve. The three-parameter Weibull distribution with Weibull exponent b = 4 also yielded excellent prediction of the relationship between fracture toughness results KJc and the cumulative probability for failure pf for one steel variant.
Numerical Investigations on the Effect of a Cuttings Bed Remover on the Cuttings Carrying Capacity in Horizontal Drilling
Authors: Cao Tong , Yu Kaian , Chen Xuyue , Zhu Hongwu , Luo Yunqing , Zhang Rui 
Published: November 2019

Abstract
With the increasing development of the exploration of unconventional oil-gas resources, people pay more and more attention to horizontal drilling technology. During the process of horizontal drilling, when the deviation angle exceeds the critical value, the falling velocity of the cuttings in annulus will increase with the deviation angle and they are more inclined to slip to the bottom edge. If the drilling parameters are chosen improperly at the same time, the cuttings would be deposited to form a cuttings bed at the bottom edge of the annulus. The high friction and high torque caused by the cuttings bed could greatly reduce the efficiency and the safety of drilling. This paper comes up with a cuttings bed remover with helical grooves to break the cuttings bed and carry cuttings based on the normal drill pipe design, builds 3D models of the cuttings bed removers with different structure parameters to analyze the cuttings carrying capacity with CFD. In addition, an investigation about the effects of the grooves design and drill pipe rotational speed have on the cuttings carrying capacity is accomplished, the grooves design parameters include the number, the length and the helical angle of the groove, and the effects are evaluated by the flow characteristics of fluid field and transportation of cuttings. The remover structure is optimized according to the simulation results, and the good performance of cuttings bed remover is verified by a field test. The whole research about the promotion of cuttings bed remover and its application shall be of great importance to the improvement of horizontal drilling efficiency and safety.
Optimum Design of Composite Pressure Vessel Based on 3-Dimensional Failure Criteria
Authors: Sakai J. , Park Y. H. 
Published: November 2019

Abstract
Anisotropic composite cylinders and pressure vessels have been widely employed in automotive, aerospace, chemical and other engineering areas due to high strength/stiffness-to-weight ratio, exceptional corrosion resistance, and superb thermal performance. Pipes, fuel tanks, chemical containers, rocket motor cases and aircraft and ship elements are a few examples of structural application of fiber reinforced composites (FRCs) for pressure vessels/pipes. Since the performance of composite materials replies on the tensile and compressive strengths of the fiber directions, the optimum design of composite laminates with varying fiber orientations is desired to minimize the damage of the structure. In this study, a complete mathematical 3D elasticity solution was developed, which can accurately compute stresses of a thick multilayered anisotropic fiber reinforced pressure vessel under force and pressure loadings. A rotational variable is introduced in the formalism to treat torsional loading in addition to force and pressure loadings. Then, the three-dimensional Tsai-Wu criterion is used based on the analytical solution to predict the failure. Finally, a global optimization algorithm is used to find the optimum fiber orientation and their best combination through the thickness direction.
Case Study on the Effect of Mean Stress on Ground Storage Vessels for Fuelling
Authors: Peters Daniel T. , Parr Myles , Naugle Matthew 
Published: November 2019

Abstract
The use of high-pressure vessels for the purpose of storing gaseous fuels for land based transportation application is becoming common. Fuels such as natural gas and hydrogen are currently being stored at high pressure for use in fueling stations. This paper will investigate the use of autofrettage in high pressure cylinders and its effects on the life of a vessel used for gas storage. Unlike many high-pressure vessels, the life is controlled by fatigue when cycled between a high pressure near the design pressure and a lower pressure due to the emptying of the content of the vessels.
Uncertainty Quantification and Sensitivity Analysis for Net Section Collapse Criterion of Pipes Under Pressure and Bending
Authors: Garud Y. S. , Stevens Gary L. 
Published: November 2019

Abstract
One of the manifestations of fatigue damage in pressurized components is the development of a crack for which the engineering assessment requires consideration of critical conditions leading to loss of functionality, especially in extreme low probability events under credible accident conditions. This assessment, especially for ductile, tough metals, has been based on the net section collapse (NSC) criterion. The typical inputs used in validating and in applying the criterion have associated uncertainties that can have considerable influence on the resulting or related assessment. The objective of this paper is to provide a formulation for this assessment to enable uncertainty quantification and sensitivity analysis for the NSC validation and application for pipes under pressure and section bending loads. The formulation is developed along the similar approach presented in recent PVP conference papers dealing with the CUF-based fatigue evaluation. The method of analysis is applied to several pipe tests over a wide range of geometries and loadings, and the results are compared with data with the objective of assessing the validity of the NSC criterion. The resulting range of expected uncertainty in the application of the NSC criterion and the ranking of controlling inputs based on the sensitivity analysis are discussed.
Power Piping Grade 91 In-Service Cracks
Authors: Cohn Marvin J. , Paterson Steve R. , Rapkin Keith , Henley Charles , Liebl Erick , Johnson Michael 
Published: November 2019

Abstract
After a power piping system has begun commercial operation, it is recommended that the initial nondestructive examination (NDE) of the welds should be developed and executed to reveal possible fabrication and early service-related material damage. The identified indications and other possible anomalies should be thoroughly documented, evaluated, and dispositioned.
Additional early service-related cracks may initiate and propagate several years after the first examination. This paper considers historical early service-related cracks in weldments of power piping systems operating in the creep regime. Factors that dominate these early service-related cracks are discussed in this paper.
This paper provides a list of more than 20 historical examples of power piping Grade 91 material macrocracks (partial wall or through-wall) that were not present immediately after construction and propagated substantially in service. Five of the examples are discussed in more detail. The study only includes cases where propagating cracks were confirmed. It does not include examples where NDE reportable indications have not propagated in service to large macrocracks. Due to the time-dependent nature of these girth weld cracks, the results of this study may be used to assist in the selection of Grade 91 reexamination locations after the power piping system (e.g., main steam, hot reheat, high pressure, or intermediate pressure) has been several years in service.
Optimizing Analysis Methodology for HPHT Equipment
Authors: Sims J. Robert , Lefkowitz Jay , Dewees Dave , Becht Charles 
Published: November 2019

Abstract
The American Petroleum Institute (API) is continuing to develop technical reports, guidelines and standards for the construction of high-pressure, high-temperature (HPHT) equipment for offshore oil and gas exploration and production. HPHT is considered to be equipment with a pressure rating greater than 103 MPa (15,000 psi) and/or a temperature rating greater than 177°C (350°F). One alternative in the evolving API standards is to use the analysis methodology in ASME Section VIII, Division 3, including fracture mechanics, for determination of the static pressure rating and the design fatigue life. However, detailed requirements for finite element analysis (FEA) parameters such as element type and mesh density are not specified. In addition, specific requirements for fracture mechanics analysis are not provided. This paper explores the effect of variations in those parameters on the calculated static pressure rating and the design fatigue life and gives recommendations for optimizing the parameters of the design itself (e.g. blend radii at transitions) and the analysis considering the required accuracy of the result, analysis time and cost.