Guojun Zhang

Huazhong University of Science and Technology

Author Statistics

Papers

Citation

H-Index

i-10 index

Research Trends

Author Order

Document Type

Co-Authors

Youmin Rong

Huazhong University of Science and Technology

Yu Huang

Huazhong University of Science and Technology

Yu Huang

Huazhong University of Science and Technology

Jiajun Xu

Shanghai Jiao Tong University

Congyi Wu

China University of Geosciences (Beijing)

Lu Wang

Huazhong University of Science and Technology

Wendong Zhang

North University of China

Xinyu Shao

Huazhong University of Science and Technology

Yong Hoon Chang

Harbin Institute of Technology

Jiang Hu

Gansu Agricultural University

Cooperative Institutions

Huazhong University of Science and Technology

Chinese Academy of Sciences

North University of China

Central South University

Shanghai Jiao Tong University

Peking University

Zhejiang University

Harbin Institute of Technology

University of Chinese Academy of Sciences

State Key Laboratory of High Performance Complex Manufacturing

Author Statistics

Papers

Citation

H-Index

i-10 index

Research Field

A new laser welding method of two transparent plastic parts based on reflector assisted method

Journal of Materials Research and Technology (2023)

Zhi Chen Zhicheng Wu Lu Shuang Guojun Zhang Hongzhi Yan

It is a challenging work to joint two transparent plastic parts using traditional laser welding because the absorptivity of transparent plastic on short wavelength (800–1000 nm) laser energy is very low. During the laser welding of two transparent plastic parts, although laser absorber and long wavelength (1600–2000 nm) laser can obtain the high-strength weld joint, the problems of unattractive weld joint or pollution will occur when laser absorber is used, and the laser energy utilization coefficient is about 70% when long wavelength laser energy is used. To address this issue, this paper proposes a new production method for the absorber-free laser welding of two transparent plastic parts based on reflector assisted method. From three-dimensional thermal model, it can be found that the simulation data of the modified Gauss cylindrical body heat source show better agreement with the experimental result than those of Gauss surface heat source and Rotary-Gauss body heat source. In addition, for the same the weld joint width on the contact surface, the reflector assisted laser welding method can decrease the laser energy consumption by about 20%. Moreover, the maximum shear force of weld joint can be up to 1315 N. Under the same process parameters, the reflector assisted method can increase the shear strength of weld joint by 15.3%. Hence, the reflector assisted method has good application and promotion value in laser welding two transparent plastic parts.

Reflector (photography)

Molar absorptivity

10.1016/j.jmrt.2023.04.108

Cite

Citations (6)

Boosting FFPE-to-HE Virtual Staining with Cell Semantics from Pretrained Segmentation Model

Lecture notes in computer science (2024)

Yihuang Hu Peng Qiong Zhicheng Du Guojun Zhang Huisi Wu

Boosting

10.1007/978-3-031-72384-1_7

Cite

Citations (0)

Learning impedance regulation skills for robot belt grinding from human demonstrations

Assembly Automation (2021)

Guojun Zhang Fenglei Ni Hong Liu Zainan Jiang Guocai Yang

The purpose of this paper is to transfer the impedance regulation of manual belt grinding to robot belt grinding control.,This paper presents a novel methodology for transmitting human impedance regulation skills to robot control in robot belt grinding. First, according to the human grinding experimental data, the skilled worker’s arm impedance regulation is calculated. Next, the human skills are encapsulated as the statistical learning model where the kernel parameters are learned from the demonstration data by Gaussian process regression (GPR) algorithms. The desired profiles of robot are generated by the task planner based on the learned skill knowledge model. Lastly, the learned skill knowledge model is integrated with an adaptive hybrid position-force controller over the trajectory and force of end-effector in robot belt grinding task.,Manual grinding skills are represented and transferred to robot belt grinding for higher grinding quality of the workpiece.,The impedance of the manual grinding is estimated by k-means++ algorithm at different grinding phases. Manual grinding skills (e.g. trajectory, impedance regulation) are represented and modeled by GMM and GPR algorithms. The desired trajectory, force and impedance of robot are generated by the planner based on the learned skills knowledge model. An adaptive hybrid position-force controller is designed based on learned skill knowledge model. This paper proposes a torque-tracking controller to suppress the vibration in robot belt grinding process.

Impedance Control

10.1108/aa-08-2020-0110

Cite

Citations (4)

High-profile-quality microchannels fabricated by UV picosecond laser for microfluidic mixing

Optics & Laser Technology (2023)

Xinhu Fan Youmin Rong Guojun Zhang Congyi Wu Yuxuan Luo

Microchannel

Micromixer

10.1016/j.optlastec.2023.110314

Cite

Citations (3)

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

Cite

Citations (62)

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

Cite

Citations (0)

Numerical simulation and experiment analysis of angular distortion and residual stress in hybrid laser-magnetic welding

Journal of Materials Processing Technology (2017)

Youmin Rong Yu Huang Jiajun Xu Haojie Zheng Guojun Zhang

Butt joint

10.1016/j.jmatprotec.2017.02.031

Cite

Citations (64)

Influence of steady magnetic field on dynamic behavior mechanism in full penetration laser beam welding

Journal of Manufacturing Processes (2017)