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Numerical analysis and experimental research on detection of welding defects in pipelines based on magnetic flux leakage

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Petroleum research 2023年第4期8卷 550-560页

作者： Changsheng Zhang Jinpeng Bi Yuexia Lv Mengli Li Yongying Qi Kai Zhou Ming Zhang Tingting Du School of Mechanical engineering Qilu University of Technology(Shandong Academy of Sciences)Jinan 250353China Shandong Institute of Mechanical Design and research Jinan 250031China CNPC Economics&Technology research Institute Beijing100120China Shandong Special Equipment Inspection Institute group Co. Ltd.Jinan 250101China School of Energy and Power engineering Shandong UniversityJinan 250061China

Regular inspection of long-distance oil and gas pipelines plays an important role in ensuring the safe transportation of oil and gas,and inspection on welding defects is an important part of the inspection *** flux leakage(MFL)is an electromagnetic non-destructive testing technique which has been commonly utilized to detect welding defects in *** the present study,Maxwell electro-magnetic simulation software was used to carry out numerical study on the welding defects in pipelines,including incomplete penetration and ***Ф406 pipeline with a wall thickness of 7 mm was selected as the study case to establish the numerical *** the life-off value at 1 mm,the distribution of magnetic leakage field was investigated for pipeline without defect,pipeline with incomplete penetration defect and pipeline with undercut defect respectively,the characteristic values describing the depth and width of defects were ***,quantified equations which can be used to describe the defect depth were ***,experimental research was carried out to validate the effectiveness of the numerical model,and the experimental results showed good consistence with the numerical calculation *** research results indicate that,it is technically feasible and reliable to diagnose the incomplete penetration and undercut welding defects in pipelines using MFL.

关键词： Magnetic flux leakage Pipeline welding defect Incomplete penetration Undercut

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An estimation of stress intensity factor in a clamped SE(T) specimen through numerical simulation and experimental verification:case of FCGR of AISI H11 tool steel

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Acta Metallurgica Sinica(English Letters) 2012年第4期25卷 307-319页

作者： Masood Shah Catherine Mabru Farhad Rezai-Aria Ines Souki Riffat Asim Pasha Mechanical engineering Department University of Engineering and TechnologyTaxilaPakistan Department of Mechanics of Structures and Materials University of Toulouse INSA UPSMines AlbiISA ICA(Institute Cl'ement Ader) DMSM F-31056 ToulouseFrance research group of Surfaces MachiningMaterials and ToolingUniversity of Toulouse INSA UPSMines AlbiISAE Campus Jarlard F-81013 Albi cedex 09France

A finite element analysis of stress intensity factors （KI） in clamped SE（T）c specimens （dog bone profile） is presented. A J-integral approach is used to calculate the values of stress intensity factors valid for 0.125≤a/W≤0.625. A detailed comparison is made with the work of other researchers on rectangular specimens. Different boundary conditions are explored to best describe the real conditions in the laboratory. A sensitivity study is also presented to explore the effects of variation in specimen position in the grips of the testing machine. Finally the numerically calculated SIF is used to determine an FCGR curve for AISI Hll tool steel on SE（T）c specimens and compared with C（T） specimen of the same material.

关键词： Fatigue crack propagation Stress intensity factor J-Integral Paris law

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Application of subfossil cladocerans(water fleas) in assessing ecological resilience of shallow Yangtze River floodplain lake systems(China)

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Science China Earth Sciences 2018年第9期61卷 1157-1168页

作者： Giri KATTEL Ke ZHANG Xiangdong YANG State Key Laboratory of Lake Science and Environment Nanjing Institute of Geography and LimnologyChinese Academy of Sciences Environmental Hydrology and Water Resources group Department of Infrastructure EngineeringThe University of Melbourne

Majority of shallow floodplain lake ecosystems of the middle and lower reaches of the Yangtze River(China) have gone through serious eutrophication problems over the recent past. The severe environmental deterioration accompanied by cyanobacterial blooms have become major water resource management challenges in the region. An advanced research method is urgently needed to tackle these challenges. The concept of ecological resilience address pressing questions of non-linear dynamics, threshold effects and regime shifts in shallow floodplain lakes, and help manage the ecosystem effectively. Palaeolimnological techniques are important for assessing long term resilience and associated thresholds effects of shallow lake ecosystems. However, the lack of reliable proxy methods available, the assessment of long term ecological resilience of shallow Yangtze River lake systems has become increasingly difficult. Cladocerans(water fleas) play a central role in lacustrine food webs by responding to external drivers and internal ecosystem processes in lakes. Their subfossils are well preserved and becoming one of potential proxy indicators of lake ecosystems change for a longer time scale. This study explores the potential application of subfossil cladocerans and their ephippia in assessing a long term ecological resilience and help better management strategies of lake ecosystems and water resources of the middle and lower reaches of the Yangtze River in China.

关键词： Subfossil cladoceran Yangtze River lake system Food web Ecological resilience Regime shift Threshold

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Hydrodynamics of A Flexible Riser Undergoing the Vortex-Induced Vibration at High Reynolds Number

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China Ocean engineering 2018年第5期32卷 570-581页

作者： REN Tie ZHANG Meng-meng FU Shi-xiao SONG Lei-jian State Key Laboratory of Ocean engineering Shanghai Jiao Tong UniversityShanghai 200240China Collaborative Innovation Centre for Advanced Ship and Deep-Sea Exploration Shanghai 200240China Marine Design&research Institute of China Shanghai 200011China Shanghai Electric Wind Power group Shanghai 200030China

This study proposed a method to obtain hydrodynamic forces and coefficients for a flexible riser undergoing the vortex-induced vibration(VIV), based on the measured strains collected from the scale-model testing with the Reynolds numbers ranging from 1.34 E5 to 2.35 E5. The riser is approximated as a tensioned spatial beam, and an inverse method based on the FEM of spatial beam is adopted for the calculation of hydrodynamic forces in the cross flow(CF) and inline(IL) directions. The drag coefficients and vortex-induced force coefficients are obtained through the Fourier Series Theory. Finally, the hydrodynamic characteristics of a flexible riser model undergoing the VIV in a uniform flow are carefully investigated. The results indicate that the VIV amplifies the drag coefficient, and the drag coefficient does not change with time when the CF VIV is stable. Only when the VIVs in the CF and IL directions are all steady vibrations, the vortex-induced force coefficients keep as a constant with time, and under"lock-in" condition, whether the added-mass coefficient changes with time or not, the oscillation frequency of the VIV keeps unchanged. It further shows that the CF excitation coefficients at high frequency are much smaller than those at the dominant frequency, while, the IL excitation coefficients are in the same range. The axial distributions of the excitation and damping region at the dominant frequency and high frequency are approximately consistent in the CF direction, while, in the IL direction, there exists a great difference.

关键词： flexible riser vortex-induced vibration vortex-induced force excitation coefficient added-mass coefficient drag coefficient

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Control mechanism of a cable truss system for stability of roadways within thick coal seams

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Journal of Central South University 2017年第5期24卷 1098-1110页

作者： YAN Hong HE Fu-lian LI Lin-yue FENG Rui-min XING Peng-fei Key Laboratory of Deep Coal Resource Mining Ministry of Education of China (School of Mines China University of Mining & Technology) Faculty of Resources and Safety engineering China University of Mining and Technology (Beijing) Guizhou Xinlian Blasting engineering group Co. Ltd. Department of Mining and Mineral Resources engineering Southern Illinois University

Cable truss systems have been widely applied in roadways with complicated conditions, such as the large cross-sections of deep wells, and high tectonic stress. However, they are rarely applied to roadways with extremely thick coal seams because the control mechanism of the system for the deformation of the roof and the separation between coal rock segments is not completely understood. By using the relationship between the support system and the roof strata, a mechanical model was established to calculate the deformation of the roof in a thick coal seam with bedding separation under different support conditions: with an anchor truss support and without support. On this basis, the research was used to deduce a method for computing the minimum pre-tightening forces in the anchor truss, the maximum amounts of subsidence and separation with, and without, anchor truss support under the roof, and the maximum subsidence and the decreasing amounts of the separation before and after adopting the anchor truss. Additionally, mechanical relationships between the minimum pre-tightening force and the anchoring force in the anchor were analyzed. By taking a typical roadway with thick coal roof as an example, the theoretical results mentioned above were applied in the analysis and testing of a roof supporting project in a roadway field to verify the accuracy of the theory: favorable experimental results were achieved. In addition, the relationships among other parameters were analyzed, including the minimum pre-tightening forces applied by the anchor truss, the angle of inclination of the anchor cable, and the array pitch. Meanwhile, the changing characteristics of the amounts of roof separation and subsidence with key parameters of the support system(such as array pitch, pre-tightening force, and inclination angle) were also analyzed. The research results revealed the acting mechanism of the anchor truss in control of roadway stability with a thick coal seam, providing a theoretic

关键词： cable truss system thick coal seam roof separation pre-tightening force

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Synthesis, Crystal Structure and Characterization of a New Manganese(Ⅱ) Complex with o-Benzoylbenzoic Acid

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Chinese Journal of Structural Chemistry 2021年第5期40卷 631-636,530页

作者： LI Wei LI Chang-Hong ZHOU Shui-Qi LI Yu-Lin KUANG Yun-Fei School of Chemistry and Materials Science Hengyang Normal UniversityHengyang 421008China School of Materials and Chemical engineering Hunan Institute of TechnologyHengyang 421002China Zhejiang Center Good-testing Service Co.Ltd. Zhejiang 321025China

A new manganese(Ⅱ) complex [Mn(C_(14)H_(9)O_(3))_(2)(C_(12)H_(8)N_(2))_(2)]·4H_(2)O(1) was synthesized with o-benzoylbenzoic acid, manganese sulfate and 1,10-phenanthroline(phen) in the mixture of acetonitrile and water solvent. It crystallizes(C_(52)H_(42)MnN_(4)O_(10), M_(r) = 937.83) in monoclinic, space group P2_(1/n) with a = 13.3528(5), b = 17.6963(6), c = 19.7889(7) A, β = 109.647(4)o, V = 4403.8(3) A3, D_(c) = 1.415 g/cm^(3), Z = 4, F(000) = 1948, μ(Mo Kα) = 0.368 mm^(-1), R = 0.0404 and w R = 0.0956. The crystal structure shows that the manganese ion is coordinated with two oxygen atoms from two o-benzoylbenzoic acid molecules and four nitrogen atoms from two phen molecules, forming a distorted octahedral coordination geometry. The TG, spectrum analysis and magnetic properties of 1 were studied.

关键词： manganese(Ⅱ)complex spectrum analysis thermal stability magnetic property

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Extended research on software hybrid testing combining reliability and directed testing

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Journal of Systems engineering and Electronics 2011年第5期22卷 856-865页

作者： Haifeng Li Yongqi Zhang Minyan Lu School of Reliability and Systems engineering Beihang University Beijing 100191 E R. China China Network Communication group Beijing 100036 P. R. China

The software reliability testing has many disadvantages in practice, such as high complexity of constructing operational profiles and poor fault detection efficiency. Oppositely, the directed testing with a high fault detection rate is incapable of estimating reliability quantificationally. To solve this problem, a hybrid testing combining reliability and directed testing as well as a reliability model based on the order statistic （OS） model were presented by Mitchell. An extended research on Mitchell＇s work is proposed. Firstly, the most proper distribution of the fault＇s failure rate which tends to be Iognormal is suggested, and a detailed form of the OS model based on Iognormal and the corresponding parameter estimation method are proposed, respectively. Secondly, an im- plementing framework for the hybrid testing is proposed. Finally, the hybrid testing and the OS model are applied on a real website system. The experimental results indicate： the hybrid testing has more efficient fault detection power and lower testing cost than the reliability testing; compared with three traditional software reliabil ity growth models, the OS model has a best or pretty estimation or prediction power for each data set; and for the failure data set collected from hybrid testing, the OS model also achieves an ac- ceptable estimation result.

关键词： hybrid testing reliability testing directed testing relia- bilitv model order statistic (OS).

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Numerical Simulation of Dynamic Response of Saturated Sand During Shield Construction

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施工技术（中英文） 2022年第9期51卷 98-105页

作者： WANG Jingyue GE Xinsheng SHANG Zhuo WU Ping ZHANG Jun College of Civil engineering Taiyuan University of TechnologyTaiyuanShanxi 030024China Taiyuan Taigong Tianhao Civil engineering testing Co. Ltd.TaiyuanShanxi 030024China Shanxi Transportation research Institute group Co. Ltd.TaiyuanShanxi 030024China

In order to study the disturbance of the liquefiable stratum caused by the vibration induced by construction of the shield machine,the construction process of the shield tunnel was simulated based on the finite difference software FLAC 3 D.A sinusoidal velocity boundary that simulates the vibration of shield construction is applied in the horizontal direction of the excavation surface,and dynamic response analysis is carried out to analyze the excess pore water pressure,acceleration,and vertical effective stress time-history *** research results show that in the liquefiable stratum,the vibration induced by shield construction will form a certain liquefaction area in the soil in front of the excavation *** area has not developed to the *** area where the vibration induced by shield construction has a great influence on the excess pore water pressure of the soil is below the excavation *** area is *** excess pore water pressure of the overlying soil layer on the excavation surface increases,and the vertical effective stress *** horizontal vibration wave induced by shield construction has no obvious attenuation in the horizontal direction,but has obvious attenuation during the propagation to the ground *** the area where the peak value of soil acceleration is large,the soil liquefaction is serious.

关键词： soil acceleration excess

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A Study on Inhibitors for the Prevention of Hydrate Formation in Gas Transmission Pipeline

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Journal of Natural Gas Chemistry 2007年第1期16卷 81-85页

作者： Ming Wu Shumiao Wang Hongbo Liu Department of Storage and Architecture engineering Liaoning University of Petroleum and Chemical Technology Fushun 113001 Liaoning China R ＆D Center Xinao Group Langfang 065001 Hebei China China Petroleum Pipeline engineering Corporation Langfang 065000 Hebei China

Gas Hydrate is usually formed during the transportation and treatment of oil and gas, resulting in the plugging of gas pipeline and equipment. Three thermodynamic calculation formulas are analyzed to deal with this problem. The lowering of the freezing point of the inhibitors △T is used to calculate the formation temperature of natural gas hydrates. This is considered to be a good approach because it is not limited by what kind and what concentration of inhibitors one uses. Besides, the rate of lowering of the freezing point could be easily measured. The result of testing methanol and mono-ethylene glycol in a reactor shows that adding 10% inhibitors to the reactor can prevent the hydrates formation. Kinetic inhibitors are favored in the present research. They are divided into two types, polymer and surface-active agents. Their characteristics, mechanisms, and application prospect are separately discussed. Polymer inhibitors exhibit better efficiency. The result of field application of VC-713 inhibiter is also given in this article. In practice, the combination of thermodynamic inhibitors and kinetic inhibitors gives better result.

关键词： natural gas hydrate thermodynamic inhibitor kinetic inhibitor polymer surface-active agents

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Upper trophic structure in the Atlantic Patagonian shelf break as inferred from stable isotope analysis

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Journal of Oceanology and Limnology 2018年第3期36卷 717-725页

作者： ZHU Guoping ZHANG Haiting YANG Yang WANG Shaoqin WEI Lian YANG Qingyuan College of Marine Sciences Shanghai Ocean UniversityShanghai 201306China National engineering research Center for Oceanic Fisheries Shanghai 201306China Polar Marine Ecosystem group Key Laboratory of Sustainable Exploitation of Oceanic Fisheries ResourcesShanghai Ocean UniversityMinistry of EducationShanghai 201306China

The Patagonian Shelf is a very productive region with dif ferent ecosystem structures. A long history of fishing in the Southwestern Atlantic Ocean combined with a complex hydrographic structure, with a permanent front over the shelf-break and dif ferent coastal frontal regions, and a wide non-frontal area in between have made the food web in this area more complex and have resulted in changes to the spatialtemporal scale. Stable isotopes of carbon and nitrogen were used to determine the trophic structure of the Patagonian shelf break which was previously poorly understood. The results indicated that the average δ^(15)N value of pelagic guild(I llex argentinus) was remarkable lower than those of the other guilds. The δ^(13)C values of almost all species ranged from-17‰ to-18‰, but S tromateus brasiliensis had a significant lower δ^(13)C value. Compared with the southern Patagonian shelf, short food chain length also occurred. The impact of complex oceanographic structures has resulted in food web structure change to the temporal-spatial scale on the Patagonian shelf. The Patagonian shelf break can be considered as a separated ecosystem structure with lower δ^(15)N values.

关键词： 13C 15N trophic structure Patagonian shelf break

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