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Grinding/Cutting technology and equipment of Multi-scale Casting Parts

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Chinese Journal of Mechanical Engineering 2022年第5期35卷 38-46页

作者： Meng Wang Yimin Song Panfeng Wang Yuecheng Chen Tao Sun key laboratory of Mechanism Theory and equipment Design Ministry of EducationTianjin UniversityTianjin 300350China State key laboratory of Digital Manufacturing equipment and technology Huazhong University of Science and TechnologyWuhan 430074China tianjin Zhongyiming technology Co. Ltd.Tianjin 300400China

Multi-scale casting parts are important components of high-end equipment used in the aerospace,automobile manufacturing,shipbuilding,and other *** features such as parting lines and pouring risers that inevitably appear during the casting process are random in size,morphology,and *** traditional manual processing method has disadvantages such as low efficiency,high labor intensity,and harsh working *** machine tool and serial robot grinding/cutting equipment do not easily achieve high-quality and high-efficiency removal of residual features due to poor dexterity and low stiffness,*** address these problems,a five-degree-of-freedom(5-DoF)hybrid grinding/cutting robot with high dexterity and high stiffness is *** on it,three types of grinding/cutting equipment combined with offline programming,master-slave control,and other technologies are developed to remove the residual features of small,medium,and large casting ***,the advantages of teleoperation processing and other solutions are elaborated,and the difficulties and challenges are *** paper reviews the grinding/cutting technology and equipment of casting parts and provides a reference for the research on the processing of multi-scale casting parts.

关键词： Multi-scale casting parts Residual features 5-DoF hybrid grinding/cutting robot Teleoperation processing

Welding Polarity Effects on Weld Spatters and Bead Geometry of Hyperbaric Dry GMAW

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Chinese Journal of Mechanical Engineering 2016年第2期29卷 351-356页

作者： XUE Long WU Jinming HUANG Junfen HUANG Jiqiang ZOU Yong LIU Jian Opto-mechatronic equipment technology Beijing Area Major laboratory Beijing Institute of Petrochemical Technology

Welding polarity has influence on welding stability to some extent, but the specific relationship between welding polarity and weld quality has not been found, especially under the hyperbaric environment. Based on a hyperbaric dry welding experiment system, gas metal arc welding（GMAW） experiments with direct current electrode positive（DCEP） and direct current electrode negative（DCEN） operations are carried out under the ambient pressures of 0.1 MPa, 0.4 MPa, 0.7 MPa and 1.0 MPa to find the influence rule of different welding polarities on welding spatters and weld bead geometry. The effects of welding polarities on the weld bead geometry such as the reinforcement, the weld width and the penetration are discussed. The experimental results show that the welding spatters gradually grow in quantity and size for GMAW with DCEP, while GMAW with DCEN can produce fewer spatters comparatively with the increase of the ambient pressure. Compared with DCEP, the welding current and arc voltage waveforms for DCEN is more stable and the distribution of welding current probability density for DCEN is more concentrated under the hyperbaric environment. When the ambient pressure is increased from 0.1 MPa to 1.0 MPa, the effects of welding polarities on the reinforcement, the weld width and the penetration are as follows： an increase of 0.8 mm for the weld reinforcement is produced by GMAW with DCEN and 1.3 mm by GMAW with DCEP, a decrease of 7.2 mm for the weld width is produced by DCEN and 6.1 mm by DCEP; and an increase of 3.9 mm for the penetration is produced by DCEN and 1.9 mm by DCEP. The proposed research indicates that the desirable stability in the welding procedure can be achieved by GMAW with DCEN operation under the hyperbaric environment.

关键词： welding polarity hyperbaric welding gas metal arc welding(GMAW) weld bead geometry spatter

Modeling of Tool-Chip Contact Length for OrthogonalCutting of Ti-6Al-4V Alloy Considering Segmented Chip Formation

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Transactions of tianjin University 2016年第6期22卷 525-535页

作者：任成祖柯志宏陈光吴靖 tianjin key laboratory of equipment Design and Manufacturing technology Tianjin University Tianjin 300072 China

In this work, the orthogonal cutting experiments on Ti-6Al-4V alloy were conducted at different cutting speeds(10—160 m/min)and feed rates(20—160 μm/rev). The tool-chip contact length was measured by the track of tool rake face; meanwhile, the chip morphology caused by the localized and overall chip deformation was characterized by the degree of segmentation and the chip compression ratio, respectively. These parameters were analyzed and calculated according to the segmented chip morphology. In addition, three modified models considering the overall chip deformation and the localized deformation of adiabatic shear band were proposed, and the constants of the models were calculated by the genetic algorithm optimization. Considering the overall and localized chip deformation, the value and variation trend of the tool-contact length predicted by these three models agreed well with the experimental results.

关键词： tool-chip contact length segmented chip Ti-6Al-4V alloy localized shear deformation

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 parameter

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

An Intelligent Fault Diagnosis Method of Multi-Scale Deep Feature Fusion Based on Information Entropy

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Chinese Journal of Mechanical Engineering 2021年第4期34卷 121-136页

作者： Zhiwu Shang Wanxiang Li Maosheng Gao Xia Liu Yan Yu School of Mechanical Engineering Tiangong UniversityTianjin 300387China tianjin Modern Electromechanical equipment technology key laboratory Tianjin 300387China

For a single-structure deep learning fault diagnosis model,its disadvantages are an insufficient feature extraction and weak fault classification *** paper proposes a multi-scale deep feature fusion intelligent fault diagnosis method based on information ***,a normal autoencoder,denoising autoencoder,sparse autoencoder,and contractive autoencoder are used in parallel to construct a multi-scale deep neural network feature extraction structure.A deep feature fusion strategy based on information entropy is proposed to obtain low-dimensional features and ensure the robustness of the model and the quality of deep ***,the advantage of the deep belief network probability model is used as the fault classifier to identify the *** effectiveness of the proposed method was verified by a gearbox *** results show that,compared with traditional and existing intelligent fault diagnosis methods,the proposed method can obtain representative information and features from the raw data with higher classification accuracy.

关键词： Fault diagnosis Feature fusion Information entropy Deep autoencoder Deep belief network

Modulation mechanism of electron energy dissipation on superlubricity based on fluorinated 2D ZIFs

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Nano Research 2024年第4期17卷 3198-3209页

作者： Yuxin Li Lei Liu Kunpeng Wang Yuhong Liu State key laboratory of Tribology in advanced equipment Tsinghua UniversityBeijing 100084China School of mechatronic Engineering Shanghai UniversityShanghai 200444China

Electron energy dissipation is an important energy dissipation pathway that cannot be ignored in friction ***-dimensional zeolite imidazole frameworks(2D ZIFs)and fluorine doping strategies give 2D Zn-ZIF and 2D Co-ZIF unique electrical properties,making them ideal materials for studying electron energy dissipation *** this paper,based on the superlubricity modulation of 2D fluoridated ZIFs,the optimal tribological properties are obtained on the 2D F-Co-ZIF surface,with the friction coefficient as low as *** experiments,density functional theory(DFT)simulation,and fluorescence detection are used to explain the mechanism of fluorine doping regulation of tribological properties from the two stages,namely energy transfer and energy ***,the energy will transfer into the friction system through the generation of electron–hole pairs under an external excitation,and release by radiation and non-radiation energy dissipation *** reduces energy transfer by altering the electronic properties and band structures of ZIFs,and slows down the charge transfer by enhancing the shielding efficiency,thus slowing the non-radiative energy dissipation rate during the energy release *** insights not only help us better understand the role of fluorine doping in improving tribological properties,but also provide a new way to further explore the electron energy dissipation pathway during friction.

关键词： superlubricity electron energy dissipation modulation two-dimensional zeolite imidazole frameworks(2D ZIFs) fluorination

Vibration absorption of parallel-coupled nonlinear energy sink under shock and harmonic excitations

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Applied Mathematics and Mechanics(English Edition) 2021年第8期42卷 1135-1154页

作者： Jian’en CHEN Wei ZHANG Jun LIU Wenhua HU tianjin key laboratory for advanced mechatronic System Design and Intelligent Control School of Mechanical EngineeringTianjin University of TechnologyTianjin 300384China National Demonstration Center for Experimental Mechanical and Electrical Engineering Education Tianjin University of TechnologyTianjin 300384China Beijing key laboratory of Nonlinear Vibrations and Strength of Mechanical Structures College of Mechanical EngineeringBeijing University of TechnologyBeijing 100124China

Nonlinear energy sink(NES)can passively absorb broadband energy from primary *** multiple NESs connected in parallel exhibit superior performance to single-degree-of-freedom(SDOF)*** this work,a linear coupling spring is installed between two parallel NESs so as to expand the application scope of such vibration *** vibration absorption of the parallel and parallel-coupled NESs and the system response induced by the coupling spring are *** results show that the responses of the system exhibit a significant difference when the heavier cubic oscillators in the NESs have lower stiffness and the lighter cubic oscillators have higher ***,the efficiency of the parallel-coupled NES is higher for medium shocks but lower for small and large shocks than that of the parallel *** parallel-coupled NES also shows superior performance for medium harmonic excitations until higher response branches are *** performance of the parallel-coupled NES and the SDOF NES is *** is found that,regardless of the chosen SDOF NES parameters,the performance of the parallel-coupled NES is similar or superior to that of the SDOF NES in the entire force range.

关键词： coupling influence nonlinear energy sink(NES) vibration absorption

Regulating electrochemical performances of lithium battery by external physical field

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Rare Metals 2024年第6期43卷 2391-2417页

作者： Shi-Kang Wang Shuai Wu Yi-Cheng Song Hassanien Gomaa Cui-Hua An Qi-Bo Deng Ning Hu School of Mechanical Engineering School of Materials Science and EngineeringHebei University of TechnologyTianjin 300401China Shanghai key laboratory of Mechanics in Energy Engineering Shanghai 200444China Department of Chemistry Faculty of ScienceAl-Azhar UniversityAssiut 71524Egypt tianjin key laboratory of Power Transmission and Safety technology for New Energy Vehicles Tianjin 300401China State key laboratory of Reliability and Intelligence Electrical equipment Key Laboratory of Advanced Intelligent Protective Equipment TechnologyMinistry of EducationHebei University of TechnologyTianjin 300130China

Lithium batteries have always played a key role in the field of new energy ***,non-controllable lithium dendrites and volume dilatation of metallic lithium in batteries with lithium metal as anodes have limited their ***,a large number of studies have shown that the electrochemical performances of lithium batteries can be enhanced through the regulation of external physical ***,it significantly hinders the growth of lithium dendrites and promoting the reaction *** review summarizes recent innovations in the investigation of various physical fields of lithium *** application of magnetic field in the synthesis of lithium battery electrode materials is *** influence factors and regulation mechanism of various physical fields on the electrochemical performance of lithium batteries are reviewed *** addition,the current research status and existing challenges,along with future directions for the evolution of lithium batteries,are minutely discussed and *** strategies for the further evolution of lithium batteries have also been provided.

关键词： Lithium battery External field assist Reaction kinetics Lithium dendrite

A Bifurcated Vascular Channel Construction Method based on Diploic Vein Characteristics

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Journal of Bionic Engineering 2019年第5期16卷 814-827页

作者： Jian Qi Jia Li Shuxian Zheng tianjin key laboratory of equipment Design and Manufacturing technology School of Mechanical EngineeringTianjin UniversityTianjin 300354China School ofMechanical Engineering Tianjin University of Technology and EducationTianjin 300222China

In skull bone tissue engineering,cells do not easily survive and proliferate in the scaffold because of the lack of nutrient transport *** address these problems,a vascular design and fabrication method based on human skull diploic vein characteristics was *** skull sample was scanned by micro-CT,and the 3D model was constructed by *** analyzing the characteristics of the diploic vein,the vascular centerline model,path model,taper model and bifurcation model were *** vascular network examples were constructed by iteration of the bifurcation *** mold method of constructing vascular scaffolds embedded within the bionic channels was *** scaffold material is PDMS,and the surface was coated with *** Human Umbilical Vein Endothelial Cells(HUVECs)were planted into the lumen of the channels for 7 days in vitro and found to be able to *** cells cultured for three days were fluorescently stained,and it was found that the cells were well attached to the surfaces of the *** vascular design and fabrication process can lay a foundation for vascularization in bone tissue engineering.

关键词： diploic vein vascular channels bifurcation model vascular mold vascular scaffold fabrication bionic