Jiajun Xu

Shanghai Jiao Tong University

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Youmin Rong

Huazhong University of Science and Technology

Yu Huang

Huazhong University of Science and Technology

Yu Huang

Huazhong University of Science and Technology

Guojun Zhang

Huazhong University of Science and Technology

Ting Lei

Henan Cancer Hospital

Chunming Wang

Huazhong University of Science and Technology

Ruolin Wu

Wuhan Institute of Technology

Lu Wang

Huazhong University of Science and Technology

Guojun Zhang

Huazhong University of Science and Technology

Chunmeng Chen

Huazhong University of Science and Technology

Cooperative Institutions

Huazhong University of Science and Technology

Chinese Academy of Sciences

Soochow University

Central South University

South China University of Technology

Fudan University

University of Science and Technology of China

Ministry of Education of the People's Republic of China

Wuhan University of Technology

University of Maryland, College Park

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Public Development Banks and Green Bond Market Development

Yuxuan Huang Jiajun Xu

Market development

10.2139/ssrn.4972418

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Magnetism aided mitigation of deformation and residual stress in dissimilar joint 316L with EH36

Journal of Materials Processing Technology (2018)

Youmin Rong Jiajun Xu Ting Lei Yu Huang Xinyu Shao

Magnetism

Weld pool

Lorentz force

10.1016/j.jmatprotec.2018.04.022

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Citations (25)

Keyhole-induced porosity formation during laser welding

Journal of Materials Processing Technology (2017)

Jiajun Xu Youmin Rong Yu Huang Pingjiang Wang Chunming Wang

Keyhole

Liquid bubble

10.1016/j.jmatprotec.2017.10.038

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Citations (110)

Highly Thermally Conductive Papers with Percolative Layered Boron Nitride Nanosheets

ACS Nano (2014)

Hongli Zhu Yuanyuan Li Zhiqiang Fang Jiajun Xu Fangyu Cao

In this work, we report a dielectric nanocomposite paper with layered boron nitride (BN) nanosheets wired by one-dimensional (1D) nanofibrillated cellulose (NFC) that has superior thermal and mechanical properties. These nanocomposite papers are fabricated from a filtration of BN and NFC suspensions, in which NFC is used as a stabilizer to stabilize BN nanosheets. In these nanocomposite papers, two-dimensional (2D) nanosheets form a thermally conductive network, while 1D NFC provides mechanical strength. A high thermal conductivity has been achieved along the BN paper surface (up to 145.7 W/m K for 50 wt % of BN), which is an order of magnitude higher than that in randomly distributed BN nanosheet composites and is even comparable to the thermal conductivity of aluminum alloys. Such a high thermal conductivity is mainly attributed to the structural alignment within the BN nanosheet papers; the effects of the interfacial thermal contact resistance are minimized by the fact that the heat transfer is in the direction parallel to the interface between BN nanosheets and that a large contact area occurs between BN nanosheets.

Nanosheet

Contact resistance

Interfacial thermal resistance

10.1021/nn500134m

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Citations (460)

Symplectic Conditions on Grassmannian, Flag, and Schubert Varieties

Communications in Mathematical Research (2024)

Jiajun Xu Guanglian Zhang

In this paper, a description of the set-theoretical defining equations of symplectic (type C) Grassmannian/flag/Schubert varieties in corresponding (type A) algebraic varieties is given as linear polynomials in Pl ücker coordinates, and it is proved that such equations generate the defining ideal of variety of type C in those of type A. As applications of this result, the number of local equations required to obtain the Schubert variety of type C from the Schubert variety of type A is computed, and further geometric properties of the Schubert variety of type C are given in the aspect of complete intersections.Finally, the smoothness of Schubert variety in the non-minuscule or cominuscule Grassmannian of type C is discussed, filling gaps in the study of algebraic varieties of the same type.

Flag (linear algebra)

Schubert variety

Schubert Calculus

Schubert polynomial

Generalized flag variety

10.4208/cmr.2023-0034

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Application and trends of point cloud in intelligent welding: State of the art review

Journal of Manufacturing Systems (2025)

Hui Wang Youmin Rong Jiajun Xu Yu Huang Guojun Zhang

10.1016/j.jmsy.2025.01.001

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Forming Mechanism of Weld Cross Section and Validating Thermal Analysis Results Based on the Maximal Temperature Field for Laser Welding

Metals (2022)

Youmin Rong Jiajun Xu

In this paper, the forming mechanism of weld cross sections (WCSs) was studied via thermal analysis. The melting of a WCS was first dominated by heat convection from the flowing melt until the WCS had the max cross section in the transient temperature field. Then, the melting was dominated by heat conduction from the residual heat in the weld pool, giving rise to an increase in middle width but a decrease in upper and bottom width. This indicated that the WCS obtained from the transient temperature field could not represent the section after solidification. Therefore, thermal analysis results should be validated using the WCS obtained from the maximal temperature field. This WCS was dependent upon the max temperature of each node over time. Compared with the former WCS, the latter one showed better adaptability in terms of multi-process parameters when the thermal analysis results were validated.

Transient (computer programming)

10.3390/met12050774

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Citations (1)

Review on finite element analysis of welding deformation and residual stress

Science and Technology of Welding & Joining (2017)

Youmin Rong Jiajun Xu Yu Huang Guojun Zhang

Welding deformation and residual stress have negative influence on assembly accuracy and service performance. Thermal elastic plastic (TEP) and inherent strain finite element analysis (FEA) methods were used to study this challenge. Basic principle of these two methods was first introduced. The influence of welding process, constraints, solid phase transformation and multi-pass welding on deformation and residual stress was discussed, and computation accuracy and efficiency were summarised. Loading method of inherent strain in inherent strain FEA was analysed, interface element was introduced to simulate effects of the gap on deformation in assembly welding especially for large structures. The future work, including accurately multiscale TEP model, efficiently transient prediction method of large structures, and flexible evaluation software, was planned.

10.1080/13621718.2017.1361673

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Citations (62)

Point cloud acquisition and dissimilar weld seam localization of vaporizer finned tubes based on real-time robot pose and laser vision

Alexandria Engineering Journal (2025)

Hui Wang Yu Huang Guojun Zhang Youmin Rong Jiajun Xu

Vaporizer

10.1016/j.aej.2025.01.039

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Stress Distribution of EH40 with Defects Considering Solid-State Phase Transformation

Welding Journal (2023)

LU WANG Youmin Rong Yu Huang Jiajun Xu Jiang Hu

Residual stress of laser-welded marine steel EH40 was experimentally and numerically analyzed considering weld defects (collapse, hump, and unfitness) and solid-state phase transformation (SSPT). A double-cylindrical source model was used to simulate the temperature distribution. The mean prediction errors of the model without and with weld defects along the plate thickness were 9.2 and 3.5%. Based on the thermodynamics of SSPT, microstructure fractions were computed and verified by weld hardness test results. Under the effect of SSPT, residual stress changed from compressive stress to tensile stress with the increase of the distance from the weld center. Weld defects have an influence on the value of residual stress, and this effect was greater when SSPT was considered. The affected zone extended from the vicinity of weld defects to the whole weld. The variations of longitudinal residual stress (LRS) and transverse residual stress (TRS) caused by weld defects and SSPT both exceeded 150 MPa. LRS was mainly affected by the loss and increase of metal, while TRS was affected by the stress concentration caused by shape geometry changes. Thus, the influence of weld defects on TRS was greater than that on LRS. The proposed finite element model considering weld defects and SSPT can be used to accurately predict residual stress in laser welding of marine steel EH40 and provide a theoretical basis to reduce welding stress.

10.29391/2023.102.024

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