bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mid-Term Energy Consumption Prediction of Crude Oil Pipeline Pump Unit Based on GSCV-SVM
Authors: Xu Lei , Hou Lei , Li Yu , Zhu Zhenyu , Liu Jiaquan , Lei Ting 
Published: October 2020

Abstract
Energy consumption prediction plays an important role in pipeline operation regulation and energy management. Accurate energy consumption prediction is helpful to make important decisions, including unit commitment, batch scheduling, load dispatching, energy consumption target setting, etc. The energy consumption of crude oil pipeline is mainly the electrical energy of pump unit. The average annual electrical energy consumption of China’s crude oil pipelines accounts for more than half of the annual operating cost of pipelines. Therefore, the prediction of electrical energy consumption of crude oil pipelines is critical.
The energy consumption prediction of crude oil pipelines is very complicated. Firstly, it depends on the variables related to operation parameter, crude oil physical property parameter, environmental parameter and equipment parameter. Secondly, its nonlinearity is strong. Thirdly, the available samples are too little. Through the study on the monthly operation data collected by the Supervisory Control And Data Acquisition (SCADA) system and energy consumption analysis, the turnover and the electrical energy consumption is selected as input variable and output variable, respectively. The support vector machines (SVM) is introduced to predict the monthly electric energy consumption of crude oil pipelines driving oil pumps. However, the generalization capability of SVM is highly dependent on appropriate parameter setting, such as penalty coefficient and kernel parameter. The selection of the optimal parameters is critical to achieving good performance in the learning process. Therefore, in order to improve the generalization ability, GridSearchCV was adopted to optimize the hyperparameters of SVM.
Taking a crude oil pipeline from Qinhuangdao City, Hebei Province to Fangshan District, Beijing as an example, the actual operation data for four consecutive years (48 months) are used for this study. The data are divided into training set and test set by stratified sampling method, which consist of 28 samples and 20 samples respectively. The mean absolute percentage error (MAPE), root mean square error (RMSE), mean absolute error (MAE) and coefficient of determination (R2) on the test set are 3.42, 21.64, 14.31 and 0.94 respectively. Compared with other five state-of-the-art prediction methods in predictive accuracy, the result shows that GSCV-SVM has the best performance in the case of small samples, and the prediction results are in good agreement with the actual data.
Investigation on Failure Behavior of Two-Elbow Piping System Models Made of the Simulation Material Under Excessive Seismic Loads
Authors: Nakamura Izumi , Kasahara Naoto 
Published: October 2020

Abstract
To investigate the failure behavior of piping systems under excessive seismic loads, shaking table tests on piping system models made of a simulation material have been executed. The simulation material adopted in the experiment was lead-antimony (Pb-Sb) alloy. The piping system model was composed of two elbows made of Pb-Sb alloy, one additional mass, and two fixed anchors. Input motions were sinusoidal wave. The failure modes of the piping system were examined by varying the additional mass and frequency of the input sinusoidal wave.
Through the excitation tests, the failure mode which was named as “ratchet and subsequent collapse” was obtained successfully. The result which was classified as “no failure after 500 cycles” was also obtained. It was found that the occurrence of the failure depended on the ratio of the input frequency to the specimen’s natural frequency, and the ratio of additional mass weight to the limit mass weight. Though the effect of higher modes on the failure behavior was necessary to be more investigated, it seemed that the tendency of dominant failure behavior was similar to that of the single-elbow specimen investigated in the previous study.
Moreover, it was confirmed that the experimental approach to use a simulation material was applicable for piping system model with multiple elbows.
Cracking Behavior of a Decommissioned Material in Light Water Reactor Environment
Authors: Chen Y. , Alexandreanu B. , Rao A. S. 
Published: October 2020

Abstract
The performance of structural materials is critical for the safe and economic operation of light water reactors. During power operation, reactor core internal materials are exposed to aggressive corrosive coolant environment, vigorous thermal/mechanical loading, and intensive neutron irradiation. Such severe service conditions can activate and enhance a wide range of degradation processes, leading to deteriorated material properties and service performance. To ensure the structural integrity and functionality of nuclear reactor components, material degradation and damage mechanisms must be understood and managed adequately. It has been recognized that there are knowledge and data gaps in the existing information and technical bases for long-term operation and aging management. In particular, post-irradiation data on fracture toughness and crack growth rate are lacking. In this work, irradiated materials harvested from a decommissioned reactor are studied for their cracking susceptibility and fracture resistance as a function of irradiation dose. The materials are a Type 304 stainless steel sectioned from the baffle plates of a pressurized water reactor after 38 years of service. Miniature compact-tension specimens about 6.5-mm thick are machined from these materials with different levels of irradiation damage, ranging from &lt; 1 to ∼50 dpa depending on the original locations with respect to the reactor core. Crack growth rate and fracture toughness J-R curve tests are performed in a low-corrosion-potential environment at ∼315°C. All samples behave similarly under cyclic loading, and no deteriorated corrosion fatigue behavior can been seen in the test environment. Under constant loads, most of samples show no elevated crack growth rates, suggesting an adequate stress corrosion cracking resistance for these irradiated samples in the test environment. An unstable cracking behavior was observed occasionally where step-wise crack advances upon load increases can be seen. The effect of neutron irradiation is evident on fracture toughness. With the increasing dose, the J-R curve declined constantly, and became very shallow at high doses. It is evident that this baffle plate material has been severely embrittled by neutron irradiation. In addition, an unexpected fully IG morphology has been observed for the all high-dose samples fractured at room temperature in air atmosphere. The occurrence of this brittle fracture in the absence of aggressive environment confirmed a high degree of embrittlement of this material resulting from its service exposure to neutron irradiation.
Finger Flange Designs on Cast Equipment
Authors: Shitole Bhaskar , Heinrichs Cynthia 
Published: October 2020

Abstract
Piping systems connecting critical equipment such as pumps with non-standard flanges should be designed so that all components have compatible strength. One such non-standard flange design is the so-called finger flange, used on the discharge flanges of large pumps. A finger flange uses slots instead of holes for the bolts. This design is common for certain types of equipment in use today, such as large slurry and water pumps.
In this study, finite element analysis is used to model a finger flange bolted to a standard ASME B16.5 weldneck flange and understand the areas of weakness in the overall joint. Seating stresses caused by bolt load are calculated as well as stresses experienced by the joint during operation with additional pressure applied. Stresses are compared for the region of highest stress at the junction of the hub to the pipe shell. Various aspects of the geometry are modified to evaluate the effect on flange stress.
The slots were found to have minimal effect on flange stress. Increasing the wall thickness reduces the stress in the finger flange. Bolting the finger flange to a thicker standard flange increases the stress in the finger flange. Uneven bolting was simulated by tightening a bolt and leaving the surrounding bolts loose. In this situation the finger flange experienced significantly higher stress than a standard flange exposed to the same uneven load. Gasket stress and displacement were similar between a finger flange joint and a standard joint.
Effect of Glaze Composition on the Corrosion Resistance of Glass Lining of Glass-Lined Pressure Vessels
Authors: Xu Jin-Sha , Tang Chen-Huai , Chen Yi , Ren Fa-Cai , Si Jun , Ding Ju , Zhang Pu-Gen , Yang Yu-Qing , Du Yan-Nan , Han Shou-Peng 
Published: October 2020

Abstract
Glass-lined pressure vessels are widely used in various corrosion conditions because of their excellent corrosion resistance. Under the same firing process condition, the corrosion-resistant properties of glass-lined vessels are largely dependent upon the glaze composition. In this paper, three kinds of glazes were selected to study the corrosion resistance to acid and alkali of the glass lining. Based on the glaze composition analysis, the corrosion quantity and the micromorphology observations of the corroded surfaces, the effect of glaze composition on the corrosion resistance to acid and alkali of glass lining was discussed. The results showed that the corrosion resistance of glass lining was mainly to the content of SiO2 and the continuity level of [SiO4] skeleton in glass network structure. The higher continuity level of [SiO4] skeleton led to the better physicochemical properties of the glass lining. The addition of the acid resistant oxide TiO2 improved the acid resistance of glass lining. The proper addition of ZrO2 improved the corrosion resistance to acid and alkali. There were two reasons, one of which was that the joining of Zr4+ into the glass network improved the structural integrity, and the other was that the reaction of Zr4+ with OH− produced Zr(OH)4 on the glass lining occurred and formed a shielding lining against alkali when glass lining was in the alkaline condition.
Application of Nonlinear Parameters Predictive Model Based on LS-SVM in Pipeline of Mixed Transportation
Authors: Li Xue , Shi Lei 
Published: October 2020

Abstract
In order to meet the refinery’s requirements on the properties of raw materials, improve the hydraulic stability of pipeline transporting process, and reduce the energy consumption, it’s necessary to mix up different crude oils transported in pipeline. The traditional method to obtain the physical properties of mixed crude oil, especially the nonlinear parameters such as viscosity and pour point, is experiment test or empirical formula, but the disadvantage is the heavy workload or limited use conditions. In this paper, a nonlinear parameters prediction model based on LS-SVM is put forward for transporting mixed crude oil in pipeline. The modeling method of the nonlinear parameters prediction based on LS-SVM : 1 normalize the different batch sample data; 2 the kernel function of SVM is Gaussian RBF; 3 regress coefficients by genetic algorithm; 4 train parameters and then obtain the nonlinear parameters prediction model. The nonlinear parameters prediction model based on LS-SVM has superiority in aspects of reliability, modeling efficiency, universality and adaptability. It can adapt to the dynamic requirements of refinery on crude oil properties, make full use of the accumulated mixed crude oils’ physical properties and their mixing ratio. The prediction accuracy of non-linear parameters model can be improved continuously. And then, the rationality and efficiency of online mixed transportation in pipeline can be improved effectively.
Elephant Foot Buckling Analysis of Large Unanchored Oil Storage Tanks With Tapered Shells Subjected to Foundation Settlement
Authors: Shi Lei , Wang Xiaolin , Chang Liang , Li Xue 
Published: October 2020

Abstract
This paper presents an numerical study on a large unanchored open-topped steel tank. The buckling behaviors of the tank are analyzed using the finite element computer package ANSYS by means of nonlinear stabilization algorithm. The effects of foundation harmonic settlement on the elephant foot buckling strength of large unanchored open-topped oil storage tanks with tapered shells under axial compression are explored by numerical modeling. Various items of actual geometrical structure which involve concrete ringwall foundation of tank, unanchored bottom with slope, shell tapering from the base to the top, wind girders and supports, top angles, stiffening rings and support plates are presented thoroughly in the non-symmetrical 3D finite element model. Geometric nonlinearity, nonlinear boundary conditions and elastic plastic material of Ramberg-Osgood model are involved simultaneously in simulate course. The obtained solutions are displayed graphically for selected values of system parameters: harmonic settlement amplitude, harmonic number, and critical buckling stress of axially compressed oil tank. The results will provide insights into the relationship between foundation harmonic settlement and buckling strength of the large cylinders.
Diagnosis of Corrosion Processes in Nuclear Power Plants Secondary Piping Structures
Authors: Manjunatha Koushik A. , Mack Andrea , Agarwal Vivek , Koester David , Adams Douglas 
Published: October 2020

Abstract
The current aging management plans of passive structures in nuclear power plants (NPPs) are based on preventative maintenance strategies. These strategies involve periodic, manual inspection of passive structures using nondestructive examination (NDE) techniques. This manual approach is prone to errors and contributes to high operation and maintenance costs, making it cost prohibitive. To address these concerns, a transition from the current preventive maintenance strategy to a condition-based maintenance strategy is needed. The research presented in this paper develops a condition-based maintenance capability to detect corrosion in secondary piping structures in NPPs. To achieve this, a data-driven methodology is developed and validated for detecting surrogate corrosion processes in piping structures. A scaled-down experimental test bed is developed to evaluate the corrosion process in secondary piping in NPPs. The experimental test bed is instrumented with tri-axial accelerometers. The data collected under different operating conditions is processed using the Hilbert-Huang Transformation. Distributional features of phase information among the accelerometers were used as features in support vector machine (SVM) and least absolute shrinkage and selection operator (LASSO) logistic regression methodologies to detect changes in the pipe condition from its baseline state. SVM classification accuracy averaged 99% for all models. LASSO classification accuracy averaged 99% for all models using the accelerometer data from the X-direction.
Evaluating the Performance of Engineered Enclosures for Piping Repairs
Authors: Halligan Troy , Vyvial Brent , Rodery Clay , Thistlethwaite Adam , Subramanian Kannan 
Published: October 2020

Abstract
Engineered enclosures for the repair of piping, often referred to as clamps, are used to restore the integrity of in-service piping components as an interim measure until the damaged components can be repaired. They are typically used in the petroleum refining and chemical process industries, nuclear and non-nuclear utilities, and other on-shore and offshore facilities in the oil and gas industry. This type of enclosure has typically been viewed as a short term repair with a limited design life. However, it is the authors’ experience that properly engineered and installed enclosures perform in a manner consistent with the design criteria covering the original piping component(s) to which they have been installed. To investigate this further, a series of tests were conducted on several engineered enclosures that had been recently removed to replace the damaged component. Tests were also conducted on several new constructed enclosures of a similar configuration and size to those that had been recently removed. An analytical approach was also performed on one such enclosure-pipe configuration to support and study the experimental results in detail. This paper presents and summarizes the tests, analyses, and results from this work. The results provide information that can benefit users, standards developers, and regulatory authorities in better understanding the considerations affecting the design life of engineered enclosures.
Comparison of 316LN Ratcheting Boundary at Room Temperature and 350 °C
Authors: Liu Caiming , Chen Xu 
Published: October 2020

Abstract
The ratcheting boundaries of 316LN austenitic stainless steel under room temperature and 350 °C were determined by efficiency curve method. The iso-cumulative plastic strain curves of the material were obtained through numerical interpolation method. It is indicated that the primary stress and secondary stress range increase with the increase of cumulative plastic deformation. Under the same cumulative plastic strain, the iso-cumulative plastic strain curve at 350 °C is higher than that at room temperature. The effective primary stress was introduced to obtain ratcheting boundary curves. The results show that the material at 350 °C has a higher ratcheting boundary compared with that at room temperature. It is indicated that, under equivalent stress condition, the bearing capacity of 316LN at 350 °C is stronger than that at room temperature. This is due to the dynamic strain aging of the material at high temperature. At 350 °C, the solid solution atoms and dislocations are pinned together, which leads to a strengthening effect on the material. The ratcheting boundary curves determined in this study are compared with relevant standards. The test results suggest that the material served in different environments should be checked by different ratcheting boundary curves.
Effect of Several Design Parameters on the Sealing Performance of Reactor Pressure Vessel
Authors: Zheng Liangang , Mi Xue , Shi Kaikai , Bai Xiaoming , Xie Hai , Zheng Bin , Yu Xiaohuan 
Published: October 2020

Abstract
In nuclear power plants, the sealing performance of reactor pressure vessel is highly related to the spring back properties of the seal ring installed between the closure head flange (upper flange) and the vessel flange (lower flange). In the finite element analysis, the sealing performance is usually described by the separation value of the upper and lower flange at the seal ring.
Considered the test results of spring back capability of seal ring in combination with a certain safety factor, the limitation of the separation between upper and lower flange at the seal ring is usually 0.2 mm. There are many design parameters, which have a huge influence on the sealing performance of pressure vessel, such as design size, material performance, bolt preload, etc.
As the reactor coolant loop is a complete, and highly relevant design system, some design parameters of pressure vessel changed may affect the whole system. Therefore, the effects of several design parameters on the sealing performance of the pressure vessel were analyzed in this paper. The results indicated that angle of the upper flange seal surface and the preload of the bolts have a big influence on the sealing performance of the pressure vessel, and they have nothing to do with the design of the whole system. The research results might guide the pressure vessel designers to optimize the pressure vessel design on improving the sealing performance.
The Influence of Multiaxial Stress Relaxation on Component Creep Damage Accumulation in Biaxial, Mixed Primary, and Secondary Loading on a Pipe
Authors: Matev Nayden , Ainsworth Robert A. , Su Meini , Stevens Mark , Jappy Alan 
Published: October 2020

Abstract
Unless detailed inelastic analysis is followed, high temperature codes base creep relaxation during a dwell period within a cycle on the start-of-dwell equivalent stress. The relaxation of the equivalent stress is then taken to be governed by a uniaxial creep law for the material being considered. Elastic follow-up is also included in such calculations. With this approach, only equivalent values of stress and creep strain rate are obtained and the stress multiaxiality is therefore assumed to remain at its initial value as the stress relaxes. The stress drop is limited to a small fraction (typically 20%) of the initial equivalent stress to ensure that this assumption does not lead to significant inaccuracy. This paper reports creep relaxation results for a pipe subjected to a combination of both primary and secondary stresses. The primary stress is generated by an internal pressure and an axial load, which enable different primary biaxial loading conditions to be generated. The secondary stress is through-wall bending in nature, produced by a through-wall temperature gradient, which influences the initial biaxial stress ratio. Several parameters are varied in order to produce relaxation behaviour in the pipe with an associated elastic follow-up. The starting biaxial stress ratio, the creep law power exponent and the amount of secondary stress result in varying degrees of elastic follow-up being present. The biaxial stress ratio is generally found to change as relaxation occurs and a multiaxial ductility approach is used to evaluate the associated effect on creep damage accumulation. This is compared with the creep damage estimated by assuming relaxation is simply controlled by the equivalent stress with no change in multiaxial stress state during relaxation. It is found that significant equivalent stress drops (up to about 40% of the initial value) can be allowed without the simplified equivalent stress approach being inaccurate. The results have been compared with a number of creep damage models to ensure that the conclusions are not sensitive to the detail of the damage model.
Parameter Sensitivity Analysis of a Beam Seal Based on a New Sealing Criterion and Orthogonal Array Method
Authors: Cui Ying , Yu Yingjia 
Published: October 2020

Abstract
A beam seal with an elliptical groove is proposed and parameterized. Based on the stochastic grid percolation model, macroscopic and microscopic finite element analysis, a sealing performance index is developed for the beam seal, which can consider the contact bandwidth and contact pressure synthetically. Taking the sealing performance index as the objective function, the sensitivity analysis of six main structural parameters of the beam seal is carried out by using the orthogonal array method. The orthogonal experiment with six factors and two levels is used to examine the interaction between parameter. It is found that there are parameter interactions between the length of the long axis and the short axis of elliptical groove, between taper angle and inclined angle U-shaped section, and between nominal contact width of the first seal and long axis of the elliptical groove. Furthermore, the sensitivity of each parameter on the sealing performance index of the beam seal is evaluated by the orthogonal design of L81(340) and F-test. The sensible parameters for sealing performance are obtained, and the optimal structural parameters of beam seal are suggested.