Accepted Manuscripts

Mohamed Saber and Ziada Samir
J. Pressure Vessel Technol   doi: 10.1115/1.4039920
The aeroacoustic sources generated by flow over a ducted shallow cavity in the presence of a longitudinal plane sound wave are examined at various Strouhal numbers and sound intensities. The cavity is exposed to high Reynolds number fully developed pipe flow. Extensive PIV flow measurements are performed to characterize the unsteady velocity field and finite element analysis is used to obtain the acoustic velocity field. Howe's aeroacoustic integrand is then used to compute the spatial and temporal distributions of the aeroacoustic sources resulting from the cavity shear layer interaction with the sound field. The results show two aeroacoustic sources separated by a sink along the cavity shear layer. This distribution is different from that reported for the closed side-branch resonance case, which shows a single source at the downstream corner and a sink at the upstream corner of the cavity. The effect of the upstream corner geometry in the present case is therefore expected to be different from the case of side-branch resonance. The time-averaged sound power distribution is computed and the total sound power per cycle is compared with the aeroacoustic source strength measured by means of the Standing Wave Method (SWM) [1]. The merits of these two methods in determining the aeroacoustic sources are highlighted.
TOPICS: Pipelines, Cavities, Corners (Structural elements), Shear (Mechanics), Resonance, Flow (Dynamics), Acoustics, Sound waves, Reynolds number, Standing waves, Finite element analysis, Pipe flow, Cycles, Flow measurement, Geometry
Seok Jun Kang, Hoomin Lee, Jae-Boong Choi and Moon Ki Kim
J. Pressure Vessel Technol   doi: 10.1115/1.4039883
Ultra Super Critical thermal plants are now in operation around the globe. Their applications include superheaters and reheaters, which generally require high temperature / pressure conditions. To withstand these harsh conditions, an austenitic heat resistant HR3C (ASME TP310NbN) steel was developed for metal creep resistance. As the designed life time of a typical thermal plant is 150,000 hours, it is very important to predict long-term creep behavior. In this study, a three-state variable continuum damage model was modified for better estimation of long-term creep life. Accelerated uniaxial creep tests were performed to determine the material parameters. Also, the rupture type and microstructural precipitation were observed by scanning electron microscopy. The creep life of HR3C steel was predicted using only relatively short-term creep test data and was then successfully verified by comparison with the long-term creep data.
TOPICS: Alloy steel, Damage, Creep, Steel, Pressure, Heat, Metals, Superheaters, Scanning electron microscopy, Precipitation, Rupture, High temperature
Technical Brief  
David S. Bartran
J. Pressure Vessel Technol   doi: 10.1115/1.4039882
Abstract: Documented thermowell failures designed to PTC 19.3TW and earlier, evaluated with the drag crisis included, reveals the potential for enhanced reliability of the current standard in reducing the risk of failure. The code calculation remains largely intact apart from a conservative Strouhal number in conjunction with Reynolds number criteria marking the onset and terminus of the drag crisis.
TOPICS: Drag (Fluid dynamics), Design, Failure, Risk, Reynolds number, Reliability
Qian Wu, Yong Wang, Tao Han and Ling Ding
J. Pressure Vessel Technol   doi: 10.1115/1.4039843
In the course of the service of long-distance oil/gas pipelines, due to corrosion, abrasion and other reasons, the possibility of pipeline leakage is growing. In-service welding is an advanced technique employed in the repair of pipelines, and it has wide application in guaranteeing the safe transmission of petroleum or gas. The present studies on in-service welding, including experiments and numerical simulations, all assumed that the inner wall of the pipeline was in good condition without considering the influence of defects. This article started from internal corrosive defects, through the finite element simulation method, investigated how the pressure of inner medium and defect size influence the burn-through of in-service welding. The results show that, compared with the intact pipe, pipeline with internal corrosive defect is more prone to burn-through. With the increase of medium pressure, the maximum radial deformation, the Von Mises stress and hoop stress value at the defect area increase. The radial deformation has a certain time effect. The depth of defect has an evident impact on the radial deformation and the stresses. The radial deformation, the Von Mises stress and hoop stress increase with the deepening of the defect, while the impacts of the defect's length and width are less obvious.
TOPICS: Welding, Pipelines, Deformation, Stress, Pressure, Hoop stress, Pipes, Petroleum, Leakage, Abrasion, Corrosion, Finite element analysis, Maintenance, Computer simulation, Simulation
Krzysztof Magnucki, Jerzy Lewinski and Rafal Cichy
J. Pressure Vessel Technol   doi: 10.1115/1.4039844
The paper is devoted to dished heads of various meridian shapes. Geometry of the shells of revolution, the membrane state and the edge effect occurring in the shells are described. Exemplary analytical and numerical FEM studies of torispherical, ellipsoidal, Cassini-ovaloidal and untypical special dished heads are presented. The results of the above two methods are compared. Moreover, numerical research of elastic buckling of the above mentioned selected heads under external pressure is carried out. Literature related to each of the considered head types is quoted and discussed, with special attention paid to the works developed in the 21st century. In concluding remarks the stress concentration and buckling of these structures are commented, with consideration of the head meridian shapes.
TOPICS: Buckling, Pressure vessels, Shapes, Shells, Finite element methods, Stress concentration, External pressure, Finite element model, Geometry, Membranes
Se-Chang Kim, Jae-Boong Choi, Hyun-Su Kim, Nam-Su Huh and Kyunghoon Kim
J. Pressure Vessel Technol   doi: 10.1115/1.4039846
Pipe-in-pipes are generally applied to the extreme environments such as deep-sea and next-generation reactors due to their functionality and robustness. Thus, it is important to estimate the fracture behaviors of pipe-in-pipes for integrity assessment of this unique piping system. In this work, the plastic collapse behaviors of pipe-in-pipes with circumferential through-wall cracks are investigated based on three-dimensional finite element limit analysis, where the crack is assumed to be located at the inner pipe of pipe-in-pipes. As for loading conditions, internal pressure, axial tension, and global bending moment are considered. In particular, the bending restraint effect induced by inter-connection between the inner and outer pipes of pipe-in-pipes are quantified through the finite element analyses considering a practical range of geometries of pipe-in-pipes. Based on the finite element analysis results, the tabular and closed-form solutions of the plastic limit loads of the circumferential through-wall cracked pipe-in-pipes are proposed, and then, validated against numerical simulations.
TOPICS: Stress, Fracture (Materials), Finite element analysis, Pipes, Collapse, Piping systems, Robustness, Tension, Seas, Pressure, Computer simulation
Run-zi Wang, Ji Wang, Jian-Guo Gong, Xian-Cheng Zhang, Shan-Tung Tu and Cheng-Cheng Zhang
J. Pressure Vessel Technol   doi: 10.1115/1.4039779
The aim of the present paper is to investigate different factors, including dwell time, strain range and strain ratio on creep-fatigue endurances in nickel-based Inconel 718 and GH4169 superalloys. We also summarize classic approaches for life assessments based on the generalizations of Coffin-Manson equation, linear damage summation and strain-range partitioning method. Each approach does have some degree of success in dealing with a specific set of creep–fatigue data. In order to evaluate the prediction capabilities of the validated approaches, a Bayesian information criterion allowing for maximum likelihood and principle of parsimony is used to select the best performing model.
TOPICS: Creep, Fatigue, Nickel, Superalloys, Damage
Mingjiang Xie, Steven Bott, Aaron Sutton, Alex Nemeth and Zhigang Tian
J. Pressure Vessel Technol   doi: 10.1115/1.4039780
Fatigue cracking is a key type of defect for liquid pipelines, and managing fatigue cracks has been a top priority and a big challenge for liquid pipeline operators. Existing inline inspection (ILI) tools for pipeline defect evaluation have large fatigue crack measurement uncertainties. Furthermore, current physics-based methods are mainly used for fatigue crack growth prediction, where the same or a small range of fixed model parameters are used for all pipes. They result in uncertainty that is managed through the use of conservative safety factors such as adding depth uncertainty to the measured depth in deciding integrity management and risk mitigation strategies. In this paper, an integrated approach is proposed for pipeline fatigue crack growth prediction utilizing inline inspection data including consideration of crack depth measurement uncertainty. This approach is done by integrating the physical models, including the stress analysis models, the damage propagation model governed by the Paris' law, and the ILI data. ILI data is used to update and adjust the model parameters for the individual pipe being considered so that a more accurate fatigue crack growth prediction can be achieved. Time-varying loading conditions are considered in the proposed integrated method by using rainflow counting method. The proposed integrated approach is compared with the existing physics based method using examples based on simulated data. Field data provided by a Canadian pipeline operator is also used to validate the proposed integrated approach.
TOPICS: Inspection, Fatigue cracks, Pipelines, Pipes, Physics, Uncertainty, Measurement uncertainty, Damage, Risk mitigation, Safety, Stress analysis (Engineering), Fracture (Materials)
S. Mohamed, H. R. Graf and S. Ziada
J. Pressure Vessel Technol   doi: 10.1115/1.4039781
The interaction of a cavity shear layer with the sound field of an acoustic mode can generate an aeroacoustic source which is capable of initiating and sustaining acoustic resonances in the duct housing the cavity. This aeroacoustic source is determined experimentally for an internal axisymmetric cavity exposed to high Reynolds number, fully developed turbulent pipe flow without the need to resolve the details of neither the unsteady flow field nor the flow-sound interaction process at the cavity. The experimental technique, referred to here as the Standing Wave Method (SWM), employs six microphones distributed upstream and downstream of the cavity to evaluate the fluctuating pressure difference generated by the oscillating cavity shear layer in the presence of an externally imposed sound wave. The results of the aeroacoustic source are in good agreement with the concepts of free shear layer instability and the fluid-resonant oscillation behaviour. The accuracy of the measurement technique is evaluated by means of sensitivity tests. In addition, the measured source is used to predict the self-excited acoustic resonance of a shallow cavity in a pipeline. Comparison of the predicted and measured results shows the excellent prediction of the self-excited acoustic resonance, including the resonance frequency, the lock-in velocity range, and the amplitude of the self-generated acoustic resonance.
TOPICS: Shear (Mechanics), Cavities, Excitation, Resonance, Acoustics, Sound waves, Reynolds number, Oscillations, Ducts, Microphones, Unsteady flow, Pressure, Flow (Dynamics), Fluids, Locks (Waterways), Turbulence, Standing waves, Pipe flow, Pipelines
Review Article  
Olawale Ifayefunmi and Jan Blachut
J. Pressure Vessel Technol   doi: 10.1115/1.4039695
It is generally accepted that the presence of imperfections in pressure vessel components can significantly reduce their buckling strength. In fact, the discrepancies between theoretical predictions and experimental results have been attributed to various kinds of existing and unavoidable imperfections. This is not a new problem but despite of substantial research effort in this area over the recent decades, it is far from being satisfactorily resolved. This review provides insight into the past findings and current activities related to the role of different types of imperfections on the buckling strength. It aims to contribute to a better understanding of the influence of imperfections on the structural stability of cones, cylinders and domes when these are subjected to external loading conditions. The review concentrates not only on the prominent role of initial geometric imperfections of the shell's generator but also on less known defects. This includes uneven axial length of cylinders, eccentricities and non-uniformities of applied load, inaccurately modelled boundary conditions, corrosion of the wall, influence of material discontinuity or crack and effect of pre-buckling deformation. The study examines: (i) how the data were obtained (analytically, experimentally and/or numerically), (ii) the type of material from which the shell structures were made, and (iii) the importance of findings of the previous works. Metallic and composite components are considered.
TOPICS: Domes (Structural elements), Buckling, Cylinders, Generators, Shells, Pressure vessels, Stress, Structural stability, Fracture (Materials), Corrosion, Boundary-value problems, Deformation, Composite materials
A. Ersin Dinçer, Zafer Bozkus and Arris S. Tijsseling
J. Pressure Vessel Technol   doi: 10.1115/1.4039696
Liquid slug flow driven by pressurized air in an inclined pipe with a downstream elbow is investigated numerically. As the liquid slug hits the elbow, the impact pressure and the associated force generated at the elbow may damage pipe supports as well as the pipe itself. It is essential for the design engineers of pipeline systems to accurately predict the pressure trace during the impact for safe operation. The slug arrival velocity and slug length (i.e. mass) at the elbow directly affect that pressure. In order to calculate these slug parameters just before the impact an improved one-dimensional model proposed in the literature is used. At the elbow, pressure variation with respect to time is calculated by a recently developed computer code which uses a two-dimensional Smoothed Particle Hydrodynamics (SPH) method. In the numerical setup, two representative initial slug lengths, one for short slugs and one for long slugs, and three different initial air tank pressures are used. The obtained numerical data are validated with available experimental results. For both short and long slugs, calculated peak pressures show great agreement with measured peak pressures.
TOPICS: Hydrodynamics, Particulate matter, Pressure, Slug flows, Pipes, Computers, Flow (Dynamics), Engineers, Design, Pipeline systems, Damage
Yue Zhang, Xiangpeng Luo and Jianfeng Shi
J. Pressure Vessel Technol   doi: 10.1115/1.4039699
Polyethylene (PE) pipe is widely used for oil and gas transportation. Slow crack growth (SCG) is the main failure mechanism of PE pipes. Current SCG resistance testing methods for PE pipes have significant drawbacks, including high cost, time-comsuming and uncertain reliability. Alternative method is in need to reduce the testing time and cost. In this paper, a numerical model is proposed by taking the viscoelastic and damage effect of PE material into account. The material behavior is described on the basis of linear viscoelastic integral constitutive model, along with damage effect in effective configuraion concept. A 3D incremental form of a viscoelastic and damage model is derived and implemented by ABAQUS UMAT. It is found that the curve of tensile displacement versus time, as well as the curve of crack opening displacement versus time from numerical results fit well with those from the standard PENT test (ASTM 1473). Based on the proposed model, SCG failure process is analyzed, and the effects of damage parameters on SCG process are furtherly studied and discussed.
TOPICS: Polyethylene pipes, Fracture (Materials), Damage, Displacement, Testing, Transportation systems, Computer simulation, Reliability, Constitutive equations, Failure mechanisms, Pipes, Failure, ASTM International
Mechri Abdelghani, Ghomari Tewfik, Djahida Djouadi and Sfiat Sid Ahmed
J. Pressure Vessel Technol   doi: 10.1115/1.4039698
This paper deals with the rupture of thin-walled ductile cylinders with isolated corrosion defects, subject only to internal pressure. It aims to propose a new solution for predicting the maximum load limit that will rupture a corroded pipeline, regardless of its material, its geometric ratio and the dimensions of the existing corrosion defect. This solution is a result of several numerical simulations by the variation of the length and depth of the defect with the assumption that the width of the defect had a negligible marginal effect. In all our numerical simulation analysis, the rupture was controlled by the Tresca failure criterion which is expressed in terms of material hardening exponent and the ultimate material stress. The proposed solution was then compared with the currently used coded methods, first B31.G, its improved version 0.85dL and then DNV-RP F101, using an experimental database compiled from existing literature. As a result, our proposed solution has been validated and has resulted in rupture ratios ranging from approximately 0.7 to 1. Furthermore, it has a tight prediction range as compared to the B31.G, 0.85dL, and the DNV-RP F101 methods.
TOPICS: Pressure, Corrosion, Pipelines, Rupture, Computer simulation, Stress, Hardening, Dimensions, Cylinders, Databases, Failure
Akira Maekawa and Tsuneo Takahashi
J. Pressure Vessel Technol   doi: 10.1115/1.4039697
This study describes inelastic seismic design of piping systems considering the damping effect caused by elastic-plastic property of a pipe support which is called an elastic-plastic support. Though the elastic-plastic support is proposed as inelastic seismic design framework in the Japan Electric Association code for the seismic design of nuclear power plants (JEAC4601), the seismic responses of the various piping systems with the support are unclear. In this study, the damping coefficient of a piping system is focused on, and the relation between seismic response of the piping system and elastic-plastic behavior of the elastic-plastic support was investigated using nonlinear time history analysis and complex eigenvalue analysis. The analysis results showed that the maximum seismic response acceleration of the piping system decreased largely in the area surrounded by pipe elbows including the elastic-plastic support which allowed plastic deformation. The modal damping coefficient increased a maximum of about seven-fold. Furthermore, the amount of the initial stiffness of the elastic-plastic support made a difference in the increasing tendency of the modal damping coefficient. From the viewpoint of the support model in the inelastic seismic design, the reduction behavior for the seismic response of the piping system was little affected by the 10% variation of the secondary stiffness. These results demonstrated the elastic-plastic support is a useful inelastic seismic design of piping systems on the conditions where the design seismic load is exceeded extremely.
TOPICS: Earthquake resistant design, Damping, Pipes, Piping systems, Stiffness, Eigenvalues, Nuclear power stations, Design, Stress, Deformation
Hoang Nam Phan, Fabrizio Paolacci and Silvia Alessandri
J. Pressure Vessel Technol   doi: 10.1115/1.4039635
Catastrophic failure of above ground storage tanks was observed during past earthquakes, which caused serious economic and environmental consequences. Many of the existing steel storage tanks were designed with outdated analysis methods and underestimated seismic loads. Therefore, the assessment of their seismic vulnerability is extremely important. Fragility functions are useful tools to quantify the seismic vulnerability of structures in the framework of probabilistic risk assessment. They give the probability that a seismic demand on a structural component exceeds its capacity. The objective of this study is to examine the seismic vulnerability of an unanchored steel storage tank based on the fragility analysis, considering both aleatoric and epistemic uncertainties. The significance of uncertain modeling parameters, attributed to the epistemic uncertainty, is first investigated with a screening study, which is based on nonlinear pushover analyses of the tank using the ABAQUS software. In this respect, a fractional factorial design and ANOVA technique have been adopted. The results indicated that the considered modeling parameters have a significant effect on the uplift behavior of the tank. The fragility curves are then developed based on a simplified model, where the uplift behavior is modeled based on static pushover analysis. Sources of uncertainty, associated with the significant parameters previously identified and the ground motion, are considered in the fragility analysis using a sampling procedure to generate statistically significant samples of the model. The relative importance of ground motion and modeling parameter uncertainties on the fragility curves of the tank is assessed and discussed in detail.
TOPICS: Steel, Modeling, Storage tanks, Accounting, Uncertainty, Probabilistic risk assessment, Computer software, Earthquakes, Failure, Probability, Structural elements (Construction), Stress, Design
Konstantinos Bakalis, Athanasia Kazantzi, Dimitrios Vamvatsikos and Michalis Fragiadakis
J. Pressure Vessel Technol   doi: 10.1115/1.4039634
A simplified approach is presented for the seismic performance assessment of liquid storage tanks. The proposed methodology relies on a nonlinear static analysis, in conjunction with suitable 'strength ratio-ductility-period' relationships, to derive the associated structural demand for the desired range of seismic intensities. In absence of available relationships that are deemed fit to represent the nonlinear-elastic response of liquid storage tanks, several Incremental Dynamic Analyses are performed for variable post-yield hardening ratios and periods in order to form a set of data that enables the fitting of the response. Following the identification of common modes of failure such as elephant's foot buckling, base plate plastic rotation and sloshing wave damage, the aforementioned relationships are employed to derive the 16%, 50% and 84% percentiles for each of the respective response parameters. Fragility curves are extracted for the considered failure modes, taking special care to appropriately quantify both the median and the dispersion of capacity and demand. A comparison with the corresponding results of Incremental Dynamic Analysis reveals that the pushover approach offers a reasonable agreement for the majority of failure modes and limit states considered.
TOPICS: Performance evaluation, Storage tanks, Dynamic analysis, Failure mechanisms, Buckling, Failure, Fittings, Rotation, Hardening, Waves, Ductility, Damage, Sloshing
Shuangmiao Zhai, Shaoping Zhou, Shaojie Chen, Bin Yang and Yong Li
J. Pressure Vessel Technol   doi: 10.1115/1.4039502
Pressure vessel plays an increasingly important role in process industries, in which its performance degradation, such as crack and corrosion, may lead to serious accidents and significant economic losses. Guided wave-based method is a cost-effective means for pressure vessel rapid interrogation. In this paper, direct-wave and fuzzy C-means clustering algorithm (FCM) are used to locate defect for pressure vessel. Finite element (FE) simulation is applied to analyze the propagation characteristics of guided waves. The experiment using the method based on direct-wave and FCM has been conducted on the barrel and head with different sensor arrays respectively. The variation rule of the direct-wave difference with different distance coefficients has been studied. By combination of the FCM, the defects on barrel and head can be detected accurately. The defect inspection experiment for pressure vessel using ellipse imaging algorithm is conducted as well. The experimental results show that the method based on direct-wave and FCM can locate the defects on barrel and head of pressure vessel effectively and accurately.
TOPICS: Pressure vessels, Waves, Algorithms, Corrosion, Finite element analysis, Process industries, Imaging, Simulation, Sensors, Inspection, Fracture (Materials), Accidents
Review Article  
Rajkumar Shufen and Uday S. Dixit
J. Pressure Vessel Technol   doi: 10.1115/1.4039206
Autofrettage is a metal forming technique widely incorporated for strengthening the thick-walled cylindrical and spherical pressure vessels. The technique is based on the principle of initially subjecting the cylindrical or spherical vessel to partial plastic deformation and then unloading it; as a result of which compressive residual stresses are set up. On the basis of the type of the forming load, autofrettage can be classified into hydraulic, swage, explosive, thermal and rotational. Considerable research studies have been carried out on autofrettage with a variety of theoretical models and experimental methods. This paper presents an extensive review of various types of autofrettage processes. A wide range of theoretical models and experimental studies are described. Optimization of an autofrettage process is also discussed. Based on the review, some challenging issues and key areas for future research are identified.
TOPICS: Autofrettage, Deformation, Metalworking, Pressure vessels, Residual stresses, Stress, Experimental methods, Optimization, Vessels, Explosives
Review Article  
Sasan Faghih, Hamid Jahed and Seyed Behzad Behravesh
J. Pressure Vessel Technol   doi: 10.1115/1.4039068
This paper provides a critical review of the advancements made in the application of the Variable Material Properties (VMP) method over the past two decades. The VMP method was originally proposed in 1997 (Jahed and Dubey, J. Press. Vessel Technol., vol. 119, no. 3, pp. 264-273, 1997; Jahed, Sethuraman, and Dubey, Int. J. Press. Vessel. Pip., vol. 71, no. 3, pp. 285-291, 1997) and further developed in 2001 (Parker, J. Press. Vessel Technol., vol. 123, no. 3, p. 271, 2001) as an elastoplastic method for the analysis of axisymmetric problems. The model was originally developed as a boundary value problem to predict the spatial distribution of stress. However, since 1997 it has been extended to include thermal effects to solve thermomechanical residual stresses; time domain to solve creep of discs and cylinders; finite deformation to solve cylinders under large strains; numerical solutions to make them more efficient; and asymmetric hardening behavior to accommodate non-slip deformation modes. These advancements, made over the past 20 years, are reviewed in this paper, and future trends and frontiers are discussed.
TOPICS: Materials properties, Vessels, Deformation, Cylinders, Creep, Residual stresses, Stress, Hardening, Temperature effects, Thermomechanics, Disks, Boundary-value problems
Yonghee Ryu, Abhinav Gupta and Ju Bu Seog
J. Pressure Vessel Technol   doi: 10.1115/1.4039004
Many studies assessing the damage from 1971 San Fernando and 1994 North Ridge earthquakes reported that the failure of non-structural components like piping systems was one of the significant reasons for shutdown of hospitals immediately after the earthquakes. This paper is focused on evaluating seismic fragility of a large-scale piping system in representative high-rise, mid-rise, and low-rise buildings using nonlinear time history analyses. The emphasis is on evaluating piping's interaction with building and its effect on piping fragility. The building models include the effects of nonlinearity in the performance of beams and columns. In the 20-story building that is detuned with the piping system, critical locations are on the top two floors for the linear frame building model. For the nonlinear building model, critical locations are on the bottom two floors. In the 8-story building that is nearly tuned with the piping system, the critical locations for both the linear frame and nonlinear models are the 3rd and 4th floors. It is observed that building nonlinearity can reduce fragility due to reduction in the tuning between building and piping systems. In the 2-story building, the nonlinear building frequencies are closer to the critical piping system frequencies than the linear building frequency; the nonlinear building is more fragile than the linear building for this case. However, it is observed that the linear building models give excessively conservative estimates of fragility than the nonlinear building models.
TOPICS: Structures, Pipes, Piping systems, Earthquakes, Failure, Damage

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