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Dynamic response of debris flows impacting curved joint check dams

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International Journal of Sediment Research 2022年第5期37卷 589-600页

作者： dongpo wang Xiaomei Zhang Wei Shen Aronne Armanini State Key Laboratory of Geohazard Prevention and Geoenvironment Protection Chengdu University of Technology Sichuan Province Geological Engineering Co. Ltd. Department of Biological Geological and Environmental Science University of Bologna Department of Civil Environmental and Mechanical Engineering University of Trento

The dynamic impact force of debris flow on dams with a curved upstream face curved was investigated using laboratory experiments and a theoretical approach. Equations describing the impact force and maximum run-up height were derived. The experiments and theoretical considerations reveal that the impact force and maximum run-up height are mainly controlled by the Froude number(Fr) reduced by the cosine of the channel slope angle(cosa). Both the impact force and the maximum run-up height have a quadratic relation with the modified Froude number(Fr/(cosa)0.5).The experimental data and the results of the theoretical approach are in good agreement, indicating that the theoretical approach can be used in practical applications. It is concluded that the comparison between the curved-joint dam and the more conventional sharp-joint dam shows no differences in the maximum impact force and run-up height for the same modified Froude *** the sharp-joint dam, the peak values of the impact force are reached more quickly than with the curved-joint dam.

关键词： Debris flow Curved-joint check-dam Impact force Maximum run-up height Impact response

Effect of Interlayers on Microstructure and Properties of 2205/Q235B Duplex Stainless Steel Clad Plate

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Acta Metallurgica Sinica(English Letters) 2020年第5期33卷 679-692页

作者： Fengqiang Xiao dongpo wang Wenbin Hu Lei Cui Zhiming Gao Lanju Zhou School of Materials Science and Engineering Tianjin UniversityTianjin 300350China Tianjin Key Laboratory of Advanced Joining Technology Tianjin UniversityTianjin 300350China Shandong High-tech Investment Corporation Jinan 250101China Shandong Iron&Steel Group Co. LTDJinan 250101China

In this research,2205/Q235 B clad plates were prepared by a vacuum hot rolling composite *** effects of adding Fe,Ni,and Nb interlayers on the bonding interface structures and the shear strengths of the clad steel plates were *** results showed that 2205 duplex stainless steel and the three interlayers produced a large amount of plastic deformation and low-angle boundaries,and the main structures were the recrystallized and deformed *** were many recrystallized grains in the microstructure of the Q235 B low-carbon steel due to the low deformation in the rolling *** Fe interlayer had better wettability with the two kinds of steel,but the lower strength led to the reduction of shear strength by about14 MPa compared with the original clad steel *** C element in the Q235 B low-carbon steel easily diffused into the Fe interlayer,and the clad steel plate attained a poor corrosion resistance because a large decarburization area was *** Nb interlayer reacted with the Mo element in the 2205 duplex stainless steel to form an Nb-Mo binary alloy,which generated long-banded *** decarburization area was also produced because the Nb reacted with the C element in the Q235 B to form hard and brittle *** a result,the shear strength was significantly reduced by about 282 MPa,and the corrosion resistance of the bonding surface was *** Ni interlayer did not react with the alloy elements in both sides,and therefore effectively prevented element diffusion and improved the corrosion resistance of the bonding *** to the low strength of the Ni interlayer and the increased number of bonding surfaces of the clad steel plates,the shear strength was reduced to some extent(about 40 MPa),but it still met the engineering application standards.

关键词： 2205/Q235B clad steel plate Fe interlayer Ni interlayer Nb interlayer Decarburization area Shear strength

Prediction of M–A Constituents and Impact Toughness in Stir Zone of X80 Pipeline Steel Friction Stir Welds

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Acta Metallurgica Sinica(English Letters) 2023年第4期36卷 573-585页

作者： Xueli wang Xin Ji Bin He dongpo wang Chengning Li Yongchang Liu Wei Guan Lei Cui Tianjin Key Laboratory of Advanced Joining Technology School of Materials Science and EngineeringTianjin UniversityTianjin 300354China

This study explored a strategy for predicting the proportion of martensite–austenite(M–A)constituents and impact toughness of stir zone(SZ)on X80 pipeline steel joints welded by friction stir welding(FSW).It is found that the welding forces,including the traverse force(F_(x)),the lateral force(F_(y))and the plunge force(F_(z)),are the key variables related to the change of welding parameters and influence remarkably the characteristics of M–A constituents and impact toughness of *** impact toughness of SZ is commonly lower than that of the base material due to the formation of lath bainite and coarsening of *** characteristics of M–A constituents in SZ are sensitive to the variation of welding parameters and respond well to the change of welding *** proportion of small island M–A constituents increases with the decrease in rotational speed and the increase in *** increase in the amount of island M–A constituents is beneficial to improve the impact toughness of *** on the above findings,a machine learning(ML)model for predicting the M–A constituents and impact toughness is constructed using the force features as the input data *** force data-driven ML model can predict the M–A constituents and impact toughness precisely and exhibits higher accuracy than ML built with welding *** is believed that the high accuracy is achieved because the force features include more details of FSW process,such as the heat generation,material flow,plastic deformation,and so on,which govern the microstructural evolution of SZ during FSW.

关键词： Friction stir welding Pipeline steel Welding force M-A constituents Impact toughness

Arc Characteristic and Metal Transfer of Pulse Current Horizontal Flux-Cored Arc Welding

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Transactions of Tianjin University 2017年第2期23卷 101-109页

作者： Fangjie Cheng Shuai Zhang Xinjie Di dongpo wang Jun Cao School of Materials Science and Engineering Tianjin University Tianjin 300072 China Tianjin Key Laboratory of Advanced Joining Technology Tianjin 300072 China China National Petroleum Offshore Engineering Co. LtdTianjin 300452 China

In this work, we utilized high-speed video photography to investigate the arc characteristics, metal transfer behavior, and welding spatter of the pulse-current flux-cored arc welding (P-FCAW) process in the horizontal position. The results indicate the presence of a stable “flux pole” during both the pulse-on and pulse-off periods when the mean current ranged from 140 to 170 A. The existence of this “flux pole” was beneficial for droplet transfer in the “axial droplet transfer” mode. With respect to welding spatter, with an increase in the welding current, we observed three kinds of spatter—explosive spatter, rebounded droplet spatter, and scattering spatter. With an increase in the pulse current from 310.6 to 345.6 A, the deflection of the arc reduced from 30.4° to 16.6°, which positively influenced the arc rigidity, particularly in the horizontal position. © 2017, Tianjin University and Springer-Verlag Berlin Heidelberg.

关键词： Bridge decks Drops Electric arc welding Flux cored arc welding (FCAW) High speed cameras High speed photography Poles Welding

New Developed Welding Electrode for Improving the Fatigue Strength of Welded Joints

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Journal of Materials Science & Technology 2002年第6期18卷 527-531页

作者： Wenxian wang, Lixing HUO, Yufeng ZHANG, dongpo wang and Hongyang JINGCollege of Material Science and Engineering, Tianjin University, Tianjin 300072, China Coll. of Mat. Sci. and Eng. Tianjin Univ. Tianjin 300072 China

A new welding electrode, low transformation temperature electrode (LTTE), was introduced in this paper. It was described in design principle, mechanics, chemical compositions of their deposited metal and manufacturing methods. It was proved that the best transformation starting temperature from austenite to martensite of the deposited metal of LTTE was at about 191℃ and it was obtained by adding alloying elements such as Cr, Ni, Mn and Mo. The microstructure of the weld metal of the LTTE was low carbon martensite and residual austenite. The compressive residual stress was induced around the weld of the LTTE and the -145 MPa in compression could be obtained in middle of weld metal. The fatigue tests showed that the fatigue strength of the longitudinal welded joints welded with the LTTE at 2×106 cycles was improved by 59% compared with that of the same type of welded joints welded with conventional E5015 and the fatigue life was increased by 47 times at 162 MPa. It is a very valuable method to improve the fatigue performance of welded joints.

关键词： Low transformation temperature electrode Compressive residual stress Fatigue strength Welded joints

Combined Cycle Fatigue Testing with Ultrasonic FrequencyComponent of S350 Steel Welded Joint

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Transactions of Tianjin University 2014年第6期20卷 435-438页

作者： Liu Yang wang dongpo Deng Caiyan Wu Liangchen Yin Danqing Gong Baoming School of Materials Science and Engineering Tianjin UniversityTianjin 300072China Tianjin Key Laboratory of Advanced Joining Technology Tianjin 300072China School of Materials Science and Engineering Henan University of Science and TechnologyLuoyang 471003China

A combined cycle fatigue （CCF） testing system with ultrasonic frequency component was developed toevaluate the CCF properties of S350 steel welded joints in this study. The fatigue testing results indicated that the S-Ncurves of CCF did not have fatigue limit, which agreed with those of pure high frequency fatigue of welded joints. TheS-N curves showed that the CCF strength of welded joints dropped greatly with the increasing interaction between highand low frequency fatigue loading. An approximation design method of CCF was presented using amplitude envelopeas the stress range.

关键词： fatigue welded joint combined cycle fatigue ultrasonic frequency

Study on arc characteristics and behavior of metal transfer in pulse current flux-cored arc welding of mild steel

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China Welding 2016年第4期25卷 42-51页

作者： Zhang Shuai Cheng Fangjie Di Xinjie wang dongpo Cao Jun Tianjin Key Laboratory of Advanced Joining Technology Tianjin University Tianjin 300072 China National Petroleum Offshore Engineering CO. LTD Tianjin 300452

The variation in arc characteristics and behavior of metal transfer with the change in pulse parameters has been studied by high speed video camera during pulse current flux-cored arc weld deposition.A comparative study of similar nature has also been carried out during flux-cored arc weld deposition in globular and spray transfer *** effect of pulse parameters has been studied by considering their mean current and arc *** arc characteristics studied by its root diameter,projected diameter and length,and the behavior of metal transfer noted by the metal transfer model and the droplet diameter have been found to vary significantly with the pulse *** observation may help in understanding the arc characteristics with respect to the variation in pulse parameters which may be beneficial in using pulse current FCAW to produce desired weld quality.

关键词： flux-cored arc welding pulse current mild steel arc characteristics metal transfer the slag column welding spatter

Sedimentary Characteristics of the Cretaceous in the Songliao Basin

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Acta Geologica Sinica(English Edition) 1993年第2期67卷 167-180页

作者： Liu Zhaojun, wang dongpo, Liu Li, Liu Wanzhu, wang Pujun, Du Xiaodi and Yang Guang Changchun University of Earth Sciences, Changchun, Jilin Sun Sheping Changchun University of Earth Sciences Changchun Jilin

The rupture of the lithosphere in Late Jurassic brought about the eruption of basaltic magma in the Songliao Basin. The evolution of the basin in Cretaceous progressed through six stages: pre-rift doming, extensional fracturing, fault subsidence, fault downwarping, downwarping and shringkage, resulting in the deposition of terrstrial facies nearly 10,000 m thick. There are different depositional sequences in these stages: the depositional period of the Early Cretaceous Shahezi and Yincheng Formations is the development stage of the down-faulted basin, forming a volcanic rock-alluvial fan-fan delta-lacustrine (intercalated with episodic turbidites)-swamp facies sequences; the period of the Early Cretaceous Dengluku Formation is the transformation stage of fault subsidence into fault downwarping of the basin, forming a sequence mainly of alluvial plain-lacustrine facies; the depositional period of the Early Cretaceous Quantou Formation-Late Cretaceous Nenjiang Formation is the downwarping stage of the basin, forming an alluvial plain-delta-lacustrine facies sequence; the period of the Late Cretaceous Sifangtai Formation-Mingshui Formation is the shringkage stage of the basin, forming again a sequence mainly of alluvial plain-alluvial fan and small relict lacustrine facies. These vertical depositional sequences fully display the sedimentary characteristics of a failed continental rift basin. Many facts indicate that the two large-scale lake invasions, synchronous with the global rise of sea level, which took place in the downwarping stage of the basin development, led to the connection between the lake and sea.

关键词： depositional sequence eustasy anoxic event Songliao Basin

Deep learning for cross-region streamflow and flood forecasting at a global scale

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The Innovation 2024年第3期5卷 99-109页

作者： Binlan Zhang Chaojun Ouyang Peng Cui Qingsong Xu dongpo wang Fei Zhang Zhong Li Linfeng Fan Marco Lovati Yanling Liu Qianqian Zhang State Key Laboratory of Mountain Hazards and Engineering Resilience Institute of Mountain Hazards and EnvironmentChinese Academy of SciencesChengdu 610299China State Key Laboratory of Geohazard Prevention and Geoenvironment Protection Chengdu University of TechnologyChengdu 610059China Data Science in Earth Observation Technical University of Munich80333 MunichGermany State Key Laboratory of Loess and Quaternary Geology Institute of Earth EnvironmentChinese Academy of SciencesXi’an 710061China Department of Civil Engineering McMaster UniversityHamiltonON L8S 4L8Canada Chengdu University of Information Technology Chengdu 610225China

Streamflow and flood forecasting remains one of the long-standing challenges in *** physically based models are hampered by sparse parameters and complex calibration procedures particularly in ungauged *** propose a novel hybrid deep learning model termed encoder-decoder double-layer long short-term memory(ED-DLSTM)to address streamflow forecasting at global scale for all(gauged and ungauged)*** historical datasets,ED-DLSTM yields a mean Nash-Sutcliffe efficiency coefficient(NSE)of 0.75 across more than 2,000 catchments from the United States,Canada,Central Europe,and the United Kingdom,highlighting improvements by the state-of-the-art machine learning over traditional hydrologic ***,ED-DLSTM is applied to 160 ungauged catchments in Chile and 76.9%of catchments obtain NSE>0 in the best *** interpretability of cross-region capacities of ED-DLSTM are established through the cell state induced by adding a spatial attribute encoding module,which can spontaneously form hydrological regionalization effects after performing spatial coding for different *** study demonstrates the potential of deep leaning methods to overcome the ubiquitous lack of hydrologic information and deficiencies in physical model structure and parameterization.

关键词： forecasting flood flow