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Process parameters-weld bead geometry interactions and their influence on mechanical properties:A case of dissimilar aluminium alloy electron beam welds

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Defence Technology（防务技术） 2018年第2期14卷 137-150页

作者： P.Mastanaiah Abhay Sharma G.Madhusudhan Reddy Defence Research and Development Laboratory KanchanbaghHyderabadTelangana 500058India Indian Institute of Technology Hyderabad Kandi CampusSangareddyTelangana 502285India Defence Metallurgical Research Laboratory KanchanbaghHyderabadTelangana 500058India

Prediction of weld bead geometry is always an interesting and challenging research topic as it involves understanding of complex multi input and multi output system. The weld bead geometry has a profound impact on the load bearing capability of a weld joint, which in-turn decides the performance in real time service conditions. The present study introduces a novel approach of detecting a relationship between weld bead geometry and mechanical properties(e.g. tensile load) for the purpose of catering the best the process could offer. The significance of the proposed approach is demonstrated by a case of dissimilar aluminium alloy(AA2219 and AA5083) electron beam welds. A mathematical model of tensile braking load as a function of geometrical attributes of weld bead geometry is presented. The results of investigation suggests the effective thickness of weld-a geometric parameter of weld bead has the most significant influence on tensile breaking load of dissimilar weld joint. The observations on bead geometry and the mechanical properties(microhardness, ultimate tensile load and face bend angle) are correlated with detailed metallurgical analysis. The fusion zone of dissimilar electron beam weld has finer grain size with a moderate evaporation and segregation of alloying elements magnesium and copper respectively.The mechanical properties of weld joint are controlled by optimum bead geometry and HAZ softening in weaker AA5083 Al alloy.

关键词： Electron beam welding AA2219 AA5083 Bead geometry Tensile breaking load

geometry dependent multipacting of a superconducting quarter-wave resonator at PKU

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Chinese Physics C 2013年第7期37卷 58-61页

作者：周奎杨柳孙国平姚中元全胜文罗星鲁向阳 State Key Laboratory of Nuclear Physics and Technology Peking University Institute of Applied Electronics Chinese Academy of Engineering Physics Institute of Modern Physics Chinese Academy of Science

A superconducting quarter-wave resonator （QWR） of frequency=162.5 MHz andβ=0.085 （β=v/c） has been designed at Peking University. The multipacting （MP） simulation and analysis for the QWR with CST Particle Studio has been performed. The simulation results reveal that there is no sign of MP with its normal operating accelerating gradients in the range of 6-8 MV/m. The accelerating gradient range that may incur MP is from about 1.4 to 3.2 MV/m, and the places where MP may be encountered are mainly located at the top part of the QWR. So the effect of different top geometries on MP has also been studied in depth. Our results show that an inward convex round roof is better than other round roofs, and plane roofs have an advantage over round roofs on the suppression of MP in general. While considering the optimization of its electromagnetic （EM） design, our initial designed model is also acceptable.

关键词： MP accelerating gradient range geometry growth rate

geometry and tectonic deformation of the seismogenic structure for the 8 August 2017 M_S 7.0 Jiuzhaigou earthquake sequence,northern Sichuan, China

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Earth and Planetary Physics 2019年第3期3卷 253-267页

作者： Feng Long GuiXi Yi SiWei Wang YuPing Qi Min Zhao Sichuan Earthquake Agency Sichuan Seistech Corporation Ltd.

To reveal the geometry of the seismogenic structure of the Aug. 8, 2017 M_S 7.0 Jiuzhaigou earthquake in northern Sichuan,data from the regional seismic network from the time of the main event to Oct. 31, 2017 were used to relocate the earthquake sequence by the tomoDD program, and the focal mechanism solutions and centroid depths of the M_L ≥ 3.5 events in the sequence were determined using the CAP waveform inversion method. Further, the segmental tectonic deformation characteristics of the seismogenic faults were analyzed preliminarily by using strain rosettes and areal strains(As). The results indicate:(1) The relocated M_S 7.0 Jiuzhaigou earthquake sequence displays a narrow ～ 38 km long NNW-SSE-trending zone between the NW-striking Tazang Fault and the nearly NSstriking Minjiang Fault, two branches of the East Kunlun Fault Zone. The spatial distribution of the sequence is narrow and deep for the southern segment, and relatively wide and shallow for the northern segment. The initial rupture depth of the mainshock is 12.5 km, the dominant depth range of the aftershock sequence is between 0 and 10 km with an average depth of 6.7 km. The mainshock epicenter is located in the middle of the aftershock region, showing a bilateral rupture behavior. The centroid depths of 32 M_L ≥ 3.5 events range from 3 to 12 km with a mean of about 7.3 km, consistent with the predominant focal depth of the whole sequence.(2) The geometric structure of the seismogenic fault on the southern section of the aftershock area(south of the mainshock) is relatively simple, with overall strike of ～150° and dip angle ～75°, but the dip angle and dip-orientation exhibit some variation along the segment. The seismogenic structure on the northern segment is more complicated; several faults, including the Minjiang Fault, may be responsible for the aftershock activities. The overall strike of this section is ～159° and dip angle is ～59°, illustrating a certain clockwise rotation and a smaller dip angle than the southern segment. The differences betw

关键词： MS 7.0 Jiuzhaigou earthquake sequence relocation focal mechanism seismogenic structure geometry tectonic deformation

geometry and kinematics of tugerming structural belt in the east of Kuqa Depression,Tarim Basin

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Petroleum Research 2021年第4期6卷 333-350页

作者： Shaoye Chai Chuanxin Li Xuesong Lu Qingong Zhuo Yanjie Gong School of Energy Resources China University of Geosciences(Beijing)Beijing100083China PetroChina Research Institute of Petroleum Exploration and Development Beijing100083China Key Laboratory of Basin Structure and Hydrocarbon Accumulation CNPCBeijing100083China

Accurate interpretation of clutter seismic reflection is of great significance to make clear the structural geometry and kinematics characteristics.Based on field investigations,boreholes and seismic data,forward modeling is carried out under the trishear model of fault-propagated fold principle,and the activity characteristics of the main faults in the study area are quantitatively analyzed using the balanced restoration technique,which may provide important indication for the potential petroleum exploration and development.The results show that separated by Tuziluoke and Tugerming fault,the structural style of the study area can be divided into the deeply buried forelimb,the kink band and the tiny anticline backlimb section.The Tuziluoke fault has been active with strong intensity since the sedimentary period of the Kuqa Formation and,which controls the formation of the growth strata in the deep buried forelimb of the Tuziluoke anticline.The Tugerming fault has been active intermittently since the end of the Jurassic,causing the strata denudation of the Late Jurassic to Paleogene in varying degrees and the development of series of regulating faults.The multi-stage tectonic activities caused the structural high of the anticline migrated from east to west.

关键词： Fault related fold Trishear geometry Kinematics Balanced restoration Kuqa depression

Solder joint geometry of tin-lead alloy and its application in electronic packaging

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中国有色金属学会会刊：英文版 1999年第4期9卷 733-740页

作者：王国忠朱其农程兆年王春青钱乙余中科院上海冶金所上海哈尔滨工业大学材料科学与工程学院黑龙江哈尔滨

By employing the minimum energy theorem, the Potential energy controlling equation, which consists of surface energy and gravitational energy for molten meniscus, was investigated. The soder joint geometry of molten tin-lead soder alloy for chip component and thin quad flat package were simulated with finite element method. The simulation results 0f solder joint geometry are coincident well with the experimental results. The solder joint geometry was applied to study the solder joint reliability for chip component RC3216.The thermal cycling tests revealed that the solder joint geometry plays an important ro1e in solder joint reliability.

关键词： tin-lead solders solder joint geometry simulation thermal cycling life

Self-evident Automated Proving Based on Point geometry from the Perspective of Wu's Method Identity

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Journal of Systems Science & Complexity 2019年第1期32卷 78-94页

作者： ZHANG Jingzhong PENG Xicheng CHEN Mao National Engineering Research Center for E-Learning Central China Normal University Institute of Computational Science and Technology Guangzhou University Chongqing Institute of Green and Intelligent Technology Chinese Academy of Sciences

The algebraic methods represented by Wu's method have made signi?cant breakthroughs in the ?eld of geometric theorem proving. Algebraic proofs usually involve large amounts of calculations, thus making it diffcult to understand intuitively. However, if the authors look at Wu's method from the perspective of identity, Wu's method can be understood easily and can be used to generate new geometric propositions. To make geometric reasoning simpler, more expressive, and richer in geometric meaning, the authors establish a geometric algebraic system(point geometry built on nearly 20 basic properties/formulas about operations on points) while maintaining the advantages of the coordinate method, vector method, and particle geometry method and avoiding their disadvantages. Geometric relations in the propositions and conclusions of a geometric problem are expressed as identical equations of vector polynomials according to point geometry. Thereafter, a proof method that maintains the essence of Wu's method is introduced to ?nd the relationships between these equations. A test on more than 400 geometry statements shows that the proposed proof method, which is based on identical equations of vector polynomials, is simple and e?ective. Furthermore, when solving the original problem, this proof method can also help the authors recognize the relationship between the propositions of the problem and help the authors generate new geometric propositions.

关键词： geometry algebra point geometry proof method based on identical equations vector geometry Wu's method

Theoretical and experimental investigation of gas metal arc weld pool in commercially pure aluminum:Effect of welding current on geometry

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Journal of Central South University 2017年第11期24卷 2556-2564页

作者： Farzadi A Morakabiyan Esfahani M Alavi Zaree S R Department of Mining and Metallurgical Engineering Amirkabir University of Technology Department of Materials Science and Engineering Faculty of EngineeringShahid Chamran University of Ahvaz

Effects of welding current on temperature and velocity fields during gas metal arc welding(GMAW) of commercially pure aluminum were simulated. Equations of conservation of mass, energy and momentum were solved in a three-dimensional transient model using FLOW-3 D software. The mathematical model considered buoyancy and surface tension driving forces. Further, effects of droplet heat content and impact force on weld pool surface deformation were added to the model. The results of simulation showed that an increase in the welding current could increase peak temperature and the maximum velocity in the weld pool. The weld pool dimensions and width of the heat-affected zone(HAZ) were enlarged by increasing the welding current. In addition, dimensionless Peclet, Grashof and surface tension Reynolds numbers were calculated to understand the importance of heat transfer by convection and the roles of various driving forces in the weld pool. In order to validate the model, welding experiments were conducted under several welding currents. The predicted weld pool dimensions were compared with the corresponding experimental results, and good agreement between simulation and preliminary test results was achieved.

关键词： simulation modeling heat transfer fluid flow AA1100 aluminum alloy finite element method (FEM) weld pool geometry temperature and velocity fields

Penetration Estimation of GMA Backing Welding Based on Weld Pool geometry Parameters

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Chinese Journal of Mechanical Engineering 2019年第3期32卷 134-144页

作者： Junfen Huang Long Xue Jiqiang Huang Yong Zou Ke Ma Opto-Mechatronic Equipment Technology Beijing Area Major Laboratory Beijing Institute of Petrochemical Technology

Penetration estimation is a prerequisite of the automation of backing welding based on vision sensing technology. However, the arc interference in welding process leads to the difficulties of extracting the weld pool characteristic information, which brings great challenges to the penetration estimation. At present, most researches focus on the extraction of weld pool geometry parameters, and the visual sensing systems are complex in structure and complicated in the image processing algorithms. The research of penetration estimation based on weld pool geometry parameters is still in the exploratory stage. The purpose of this paper is to research the relationship between the weld pool geometry parameters and the penetration during backing welding and to estimate penetration using the weld pool geometry parameters. A passive vision sensing test system for gas metal arc (GMA) backing welding was established. An image processing algorithm was developed to extract the weld pool geometry parameters, namely, the area, maximum width and length, half-length, length-width ratio and advancing contact angle (simplified as AWP, MWWP, MLWP, HLWP, LWR and ACA, respectively). The corresponding relationships between the weld pool geometry parameters and the penetration state were explored by analysing their changes with the welding current and speed. The distribution of the weld pool geometry parameters corresponding to penetration was determined. When the AWP of the weld pool is within a certain range and the values of LWR and ACA are close to their maximum and minimum respectively, the penetration is in good condition. A mathematical model with the weld pool geometry parameters as independent variables and the back-bead width (the indicator of the penetration state) as a dependent variable was established based on multivariable linear regression analysis, and relevant statistical tests were carried out. Multivariable linear regression equations for the weld pool geometry parameters and the back-bead width were deduced according

关键词： Welding automation Passive vision sensing Weld pool geometry parameters Penetration state Mathematical model

On the role of geometry in geo-localization

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Computational Visual Media 2021年第1期7卷 103-113页

作者： Moti Kadosh Yael Moses Ariel Shamir Department of Electrical Engineering Tel-Aviv UniversityTel-AvivIsrael The Efi Arazi School of Computer Science The Interdisciplinary Center HerzliyaHerzliyaIsrael

Consider the geo-localization task of finding the pose of a camera in a large 3 D scene from a single image.Most existing CNN-based methods use as input textured images.We aim to experimentally explore whether texture and correlation between nearby images are necessary in a CNN-based solution for the geo-localization task.To do so,we consider lean images,textureless projections of a simple 3 D model of a city.They only contain information related to the geometry of the scene viewed(edges,faces,and relative depth).The main contributions of this paper are:(i)to demonstrate the ability of CNNs to recover camera pose using lean images;and(ii)to provide insight into the role of geometry in the CNN learning process.

关键词： geo-localization geometry CNN-based solutions synthetic lean images