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2021 5th International Conference on Fluid Mechanics and Industrial Applications, FMIA 2021

作者： Shi, Haoming Shan, Zhongde Guo, Zhi Yan, Dandan State Key Laboratory of Advanced Forming Technology and Equipment Academy of Machinery Science and Technology Group Co.Ltd Beijing China Nanjing University of Aeronautics and Astronautics Jiangsu Nanjing China School of Mechanical Engineering University of Science AndTechnology Beijing Beijing China

To achieve the precise forming of sand mold for 3D printing, the relationship between the printhead intake and the pressure fluctuation in the printhead during startup and printing of sand mold 3D printer was studied, and the relationship between the two and the causes of pressure fluctuation is analyzed. With the help of computational fluid dynamics and Fluent software, the internal flow model at a single nozzle is established, and the ink flow under 10 groups of different inlet velocities is simulated to obtain the flow contour and pressure fluctuation values. Combined with the small-channel gas-liquid flow pattern, the relationship among the air intake velocity and the pressure fluctuation and the reasons for the pressure fluctuation are analyzed. The results show that with the increase of intake velocities, the pressure fluctuation amplitude increases. In addition, the disturbance degree of gas-liquid interface wave leads to the difference of pressure fluctuation amplitude as the gas-liquid flow pattern changing. The simulation results agree with the experiments. Therefore, according to the relationship between the intake velocity and the pressure fluctuation amplitude, the stability of the printing system can be improved by limiting the speed ratio of supply pump and return pump. © Published under licence by IOP Publishing Ltd.

关键词： Flow patterns

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Experimental and Simulation Study of Heat Transfer and Flow in Molten Pool During Single Layer Multi-Pass Deposition Process

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SSRN 2024年

作者： Huang, Wenhao Zhong, Haihui Wu, Na Jia, Yazhou Sun, Shiqi Li, Xiaoxu College of Mechanical and Electrical Engineering Wenzhou University Wenzhou China School of Mechanical-Electronic and Vehicle Engineering Beijing University of Civil Engineering and Architecture Beijng China College of Materials Engineering North China Institute of Aerospace Engineering Langfang China State Key Laboratory of Advanced Forming Technology and Equipment China Academy of MachineryScience & Technology Beijing China

Laser wire additive manufacturing is widely used in aerospace, space and other fields due to the advantages of high material utilization. In the additive process, the re-melting and fusion of the current pass with the previous pass is involved in order to obtain a deposited part with a flat surface, and the overlap rate greatly affects the formation of multiple passes. And the heat transfer and flow behavior of the molten pool plays a crucial role in the formation of components. Due to the limited understanding of the heat transfer process and kinetic behavior inside the molten pool through experiments, it is especially difficult to study the fluid dynamics inside the molten pool. Therefore, this paper establishes a three-dimensional transient numerical model for laser wire additive manufacturing of 5A06 aluminum alloy to study the heat transfer and flow behavior of the molten pool in the single-layer multi-pass additive process of laser wire additive manufacturing. On this basis, we analyze the changing law of the temperature field and flow field of the molten pool in the process of additive manufacturing, investigate the influence of the heat transfer and internal flow pattern of the molten pool on the deposition geometry, take the optimal lap rate range as a reference, carry out the determination of the more accurate lap rate, and finally analyze the range of the optimal lap rate according to the geometric flatness model. © 2024, The Authors. All rights reserved.

关键词： 3D printing

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Modeling and simulation of 3D topographies of slot milled walls and floor surface considering slot bi-sided wall constraints

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Journal of Manufacturing Processes 2025年 149卷 241-257页

作者： Wenjun Lyu Zhanqiang Liu Bing Wang Yukui Cai Xiaoliang Liang Liangliang Li School of Mechanical Engineering Shandong University Jinan 250061 PR China State Key Laboratory for High-end Equipment and Advanced Technology of Metal Forming Shandong University Jinan 250061 PR China Key Laboratory of High-efficiency and Clean Mechanical Manufacture of Ministry of Education Jinan 250061 PR China Key National Demonstration Center for Experimental Mechanical Engineering Education Jinan 250061 PR China School of Mechanical Electrical & Information Engineering Shandong University Weihai 264209 PR China Shenyang Aircraft Corporation Shenyang 110850 PR China

The deflection of long-cantilever length milling cutter significantly influences both surface morphology and dimensional precision during milling operations. Three surfaces are formed concurrently, including two walls and one floor surface in the one-pass slot milling operation. The cutting tool-edges concurrently make contacts with the floor surface and bi-sided walls of the slot. The bi-sided walls of the slot impose complex contact constraints on the cutting tool-edges, and the loaded force situation of the milling cutter is complex. The application of cantilever beam theory for calculating cutter deflection in planar milling is no longer applicable to one-pass slot milling. This study proposes a novel predictive framework for surface morphology in one-pass slot milling operations, incorporating time-dependent tool deflection. Firstly, the contact and force between cutting tool-edges and slot bi-sided walls and floor surface were analyzed. Secondly, the milling tool deflection models were proposed accounting for varying contact conditions of the cutting tool-edges with the slot bi-sided walls. The universal methodology for calculating tool deflection, applicable to various milling tool deflection models, has been developed. Then, the time-dependent milling force during one-pass slot milling was derived by considering time-dependent tool deflection. Numerical calculations were performed on the instantaneous cutter deflection. Finally, the bi-sided walls and floor surface topographies of slot milling were simulated and reconstructed by accounting for milling parameters, tool installation errors, random wear errors of milling tool, time-dependent milling forces and tool deflection. This framework can be embedded as a functional module in smart machining centers, enabling prediction and control of surface characteristics and dimensional accuracy.

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Effect of the configuration and concentration of B-doping on the thermal properties and structural stability of graphene: A theoretical study

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Diamond and Related Materials 2025年 156卷

作者： Li, Dongbo Da, Liangguo Huang, Kaifeng Li, Dong Yu, Liang Wang, Haini Yu, Yaqi Wu, Long Tang, Yunqing School of Mechanical and Electrical Engineering Huainan Normal University Huainan232038 China Human-computer collaborative robot Joint Laboratory of Anhui Province Huainan232038 China School of Mechanical Engineering Shandong University Jinan250061 China State Key Laboratory of Advanced Equipment and Technology for Metal Forming Shandong University Jinan250061 China Key Laboratory of High Efficiency and Clean Mechanical Manufacture Ministry of Education Shandong University Jinan250061 China

The thermal properties and structural stability of B-doped graphene were investigated by employing density functional theory (DFT), ab initio molecular dynamics (AIMD), and molecular dynamics (MD) simulations, with a focus on the effects of doping configuration and concentration. DFT calculations indicate that B-doping reduces the cohesive energy of graphene, consequently diminishing its structural stability. Among the three B double-doping configurations, only the para configuration exhibits a phonon dispersion without imaginary frequencies, whereas both meta and ortho configurations show imaginary frequencies, indicating structural instability. The AIMD results further demonstrate that B-doped graphene preferentially undergoes cleavage at B[sbnd]B bonds, leading to decreased structural stability. MD results show that B-doping significantly reduces the thermal conductivity of graphene. At a doping concentration is 0.6 %, the thermal conductivity of meta and para configurations decreases to 48.08 % and 54.6 % of that of the pristine graphene, respectively. The results of phonon properties show that B-doping reduces the phonon participation rate and induces strong phonon localization at the B-doped site. These results and conclusions will provide valuable theoretical insights for the thermal design of graphene-based semiconductor devices. © 2025 Elsevier B.V.

关键词： Temperature distribution

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High Energy Nitrogen Ion-Beam Implantation Induced Nucleation and Crystalline Growth in Amorphous Carbon Nitride Films

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SSRN 2023年

作者： Liu, Dong-Guang Zhou, Si-Wei Zou, Jin-Xin Zhang, Peng Liang, Yan Hong, Chunfu Anhui Province Key Lab of Aerospace Structural Parts Forming Technology and Equipment Hefei University of Technology Hefei230009 China State Key Laboratory of Solid Lubrication Lanzhou Institute of Chemical Physics Chinese Academy of Sciences Lanzhou730000 China Institute of Industry and Equipment Technology Hefei University of Technology Hefei230009 China State Key Laboratory of Tribology Tsinghua University Beijing100084 China School of Materials Science and Engineering Hefei University of Technology Hefei230009 China Hospital of Hefei University of Technology Hefei University of Technology Hefei230009 China Fujian Provincial Key Laboratory of Advanced Materials Processing and Application Fujian University of Technology Fuzhou350118 China

High-energy N+ injection-induced crystallization in amorphous carbon nitride (a-CN) films were observed by injecting different N+ energies. The results of the study indicated that during the initial N+ implantation, a number of nano-clusters with the size of 2-5 nm were formed and accompanied by the appearance of crystalline particles. Most of the nanocrystalline grains have the same crystallographic orientation, and the lattice parameters of these crystalline phases are very consistent with those of the graphite like carbon nitride (g-C3N4). Raman spectrum and XPS analysis also support the presence of sp2 hybridized C-N bond in N+ implanted C-N films. The Crystallization behavior and crystallization rate of the films are closely related to the N+ energy, and the mechanism and model of N+ irradiation-induced crystallization are discussed. High N+ implantation can provide high bombardment ions and high temperatures, which are the key to the structural evolution of the deposited C-N thin films. When the implanted energy is 15 keV, there is no enough energy to crystallize the grains, resulting in the local disorder during growth process. With the increase of the N+ energy (60 keV), high energy N+ alleviates the disordered state in a-matrix, arousing atomic rearrangement and the aggregation of sp2 phase. At the same time, high energy N+ bring about high temperature that cause growth formation of the nc g-C3N4. © 2023, The Authors. All rights reserved.

关键词： Crystallization

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Mechanical properties and wear behaviors of lightweight Al3Ti-based medium-entropy alloys at elevated temperatures

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Wear 2025年

作者： Diao, Guijiang He, Anqiang Zhang, Dong Tang, Yunqing Zhou, Yefei Xu, Zhen Chen, keyang Kumar, Aakash Mousavi, Seyed Elias Wu, Mingyu Chen, Wengang Chen, D.L. Li, D.Y. Department of Chemical and Materials Engineering University of Alberta EdmontonABT6G 2H5 Canada State Key Laboratory of Advanced Equipment and Technology for Metal Forming Shandong University Jinan250061 China State Key Laboratory of Metastable Materials Science & Technology Yanshan University Qinhuangdao066004 China Shi-changxu Innovation Center for Advanced Materials Institute of Metal Research Chinese Academy of Sciences Shenyang110016 China School of Machinery and Transportation Southwest Forestry University Kunming650224 China Department of Mechanical Industrial and Mechatronics Engineering Toronto Metropolitan University TorontoONM5B 2K3 Canada

Al3Ti-based medium-entropy alloys (MEAs) with improved high-temperature mechanical properties and wear resistance were fabricated using arc melting method via alloying Al3Ti with various amounts of Cr, Mn, Fe and Cu elements. The alloying elements, Cr, Mn, Fe, and Cu, transformed the brittle D022 structure into a ductile L12 structure, along with the formation of hard B2 and D8a second phases. The resultant combination of improved ductility and strength enhances the mechanical performance of the material. A representative alloy, Al60Ti20Cr5Mn5Fe5Cu5, achieved high yield strength and high hardness of 442 MPa and 270HV2 at even 500 °C. Wear tests showed that the Al3Ti-based MEAs distinctly outperformed conventional Al-matrix composite reinforced with 30 wt% of SiC particles at both room temperature and 300 °C. The ordered L12, B2, and D8a phases not only led to good room-temperature strength and hardness, but also contributed to high thermal stability, contrasting with solid solution alloys, resulting in superior high-temperature performance. The results highlight Al3Ti-based MEAs as competitive candidates for medium-temperature applications, bridging the gap between aluminum and titanium alloys in engineering applications. © 2025 The Author(s)

关键词： Titanium alloys

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Control technology of five-axis linkage forming for digital casting sand mold

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Jisuanji Jicheng Zhizao Xitong/Computer Integrated Manufacturing Systems, CIMS 2020年第9期26卷 2321-2330页

作者： Peng, Baoying Shan, Zhongde Liu, Feng Hou, Mingpeng Dai, Wenqiang State Key Laboratory of Advanced Forming Technology and Equipment China Academy of Machinery Science and Technology Beijing100044 China

Digital forming technology without pattern casting has the advantages of less pollution, short cycle and low cost. More and more casting sand molds of complex and thin-walled castings are formed by using five-axis linkage high-speed machining. The kinematical model of five-axis linkage with B-C double head for sand mold forming was derived on the basis of Rotation Tool Center Point (RTCP). The computing method of vector speed and the mechanism of speed fluctuation were analyzed. According to the constraint relationship between the ratio of each axis speed and the ratio of each axis position changing, the scheme that the overall speed control of five-axis linkage high-speed machining realized by single axis speed look ahead control was proposed, and the calculation method of look ahead threshold was given. Based on the open control system, the forward and inverse kinematics solutions of five-axis linkage RTCP were developed. The experiments including five-axis machining of impeller sand mold and look ahead control of Z axis were conducted. The experimental results showed that the proposed forward and reverse kinematics solutions of RCTP and the single axis look ahead control strategy was an effective control method for sand mold five-axis linkage high-speed forming. © 2020, Editorial Department of CIMS. All right reserved.

关键词： Speed

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Software and Application of Big Data Analysis Platform for Complex Casting Manufacturing Process Quality 75

Software and Application of Big Data Analysis Platform for C...

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75th World Foundry Congress, WFC 2024

作者： Zhou, Jianxin Zhou, Wenhao Yu, Peng Li, Wen Ji, Xiaoyuan Yin, Yajun Shen, Xu Zhang, Meijuan Qie, Xiwang Nan, Hai Zhu, Shouqin Xie, Mingguo Wang, Yu Li, Hulin Liu, Xiao Zhang, Baoming Yao, Gang Wang, Chuansheng Wang, Donghong Hu, Jianping Qian, Xuewen State Key Laboratory of Material Processing and Die & Mould Technology Huazhong University of Science & Technology Wuhan430074 China Baimtec Material Co. Ltd. Beijing100094 China Hefei Casting and Forging Factory of Anhui Heli Co. Ltd. Hefei230000 China Xi’an Aerospace Engine Co. Ltd. Xian710000 China CRCC High-Tech Equipment Co . Ltd. Kunming650215 China Guizhou Aircraft Engine Precision Casting Co. Ltd. Guiyang550014 China Wuxi Branch of FAW Casting Co. Ltd. Wuxi214177 China Shanghai Key Laboratory of Advanced High-temperature Materials and Precision Forming Shanghai Jiao Tong University Shanghai200240 China Wuhan Yimo Technology Co. Ltd. Wuhan430074 China Wuhan Huazhu Information Technology Co. Ltd. Wuhan430074 China

The complex castings used in major equipment in industries such as aerospace, automotive, rail transportation, and engineering machinery are prone to defects such as porosity, deformations, and inclusions due to the coupling effects and fluctuations of key process parameters. This leads to common problems such as "key quality points exceeding standards" and large quality fluctuations, seriously affecting the reliability and stability of major equipment manufacturing products. In this paper, a systematic study on the model-method-technology of typical defect quality big data was conducted. Firstly, relevant models were constructed, such as the single piece quality tracing model, the multi-source heterogeneous information fusion model, the model of production parameters and intrinsic relationship of typical defects, and the model of comprehensive element time-varying disturbance and defect evolution mapping. Then, five key technologies were developed, including high-precision and efficient online monitoring and prediction of typical defects, tracing the causes of quality problems in multiple links, and quality control based on the relationship between production fluctuations and metallurgical defect evolution. Based on the above research, data collection, cleaning, mining, sensitivity analysis, and relationship modeling algorithms were established for the casting production process. Special core algorithms for predicting defects such as shrinkage, looseness, and gas entrapment were proposed, achieving high-precision prediction of typical defects. A "1+N" quality big data analysis software and hardware integrated platform was developed. After applying the integrated platform to the five major industries of aerospace, automotive, rail transportation, engineering machinery, and aerospace industries, the results showed an accuracy of quality prediction of ≥80% and a reduction in defects of ≥ 30%, leading to the formulation of solutions and key demonstrations in these indu

关键词： Aerospace industry

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Enhanced high-temperature strength of a Mg-4Sn-3Al-1 Zn alloy with good thermal stability via Mg2Sn precipitation

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Journal of Magnesium and Alloys 2025年

作者： Sun, Wei Deng, Yangchao Hu, Yuhan Zhan, Hongyi Yan, Kun Shuai, Sansan Guo, Enyu Zheng, Zebang Zeng, Guang School of Materials Science and Engineering Central South University Changsha410083 China China Science Lab General Motors Global Research and Development Shanghai 201206 China Department of Materials The University of Manchester ManchesterM13 9PL United Kingdom State Key Laboratory of Advanced Special Steels School of Materials Science and Engineering Shanghai University Shanghai 200444 China School of Materials Science and Engineering Dalian University of Technology Dalian116024 China State Key Laboratory of Solidification Processing Shaanxi Key Laboratory of High-Performance Precision Forming Technology and Equipment School of Materials Science and Engineering Northwestern Polytechnical University P.O.Box 542 Xi'an710072 China

With the growing demand for rapid and cost-effective solutions for lightweight magnesium alloys with excellent high-temperature mechanical properties, we investigated a heat-treatable RE-free magnesium alloy, Mg-4Sn-3Al-1Zn (TAZ431, wt.%), with remarkable thermal stability. The peak-aged TAZ431 alloy exhibits a 15 % increase in high-temperature (230 °C) yield strength, compared to the traditional commercial magnesium alloy, Mg-3Al-1Zn (AZ31, wt.%). In this work, we demonstrate that the basal Mg2Sn precipitates have a more pronounced hindrance effect on the non-basal slip systems, as evidenced by a combination of experiments (in-situ EBSD and dual beam TEM) and numerical simulations (Orowan model and VPSC). The distribution and morphology of Mg2Sn precipitates and cracks are quantitatively analyzed using a range of techniques including in-situ SEM and synchrotron X-ray tomography. Our results reveal that the decohension of grain boundary precipitates significantly promotes the formation of intergranular cracks, leading to ultimate fracture. The research comprehensively explains the impact of particle morphology, orientation, and distribution on precipitation strengthening and fracture modes at elevated temperatures, which is vital for the future development of high-temperature performance magnesium alloys. © 2025

关键词： Cracks

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Numerical modeling and simulation for microneedles drug delivery: A novel comprehensive swelling-obstruction-mechanics model

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European Journal of Pharmaceutics and Biopharmaceutics 2025年 206卷 114583页

作者： Yang, Peijing Song, Qinghua Zhang, Lujie Liu, Zhanqiang Ma, Haifeng School of Mechanical Engineering Shandong University Jinan 250061 China State Key Laboratory of Advanced Equipment and Technology for Metal Forming Shandong University Jinan 250061 China Key Laboratory of High Efficiency and Clean Mechanical Manufacture Ministry of Education Jinan 250061 China Key National Demonstration Center for Experimental Mechanical Engineering Education Jinan 250061 China School of Mechanical Electrical & Information Engineering Shandong University Weihai 264209 China

Hydrogel microneedles have attracted significant attention in drug delivery due to their non-invasiveness and efficient administration. However, a thorough understanding of the drug transport mechanism is essential to achieve controlled drug delivery and geometry optimization of microneedles. In this study, a new swelling-obstruction-mechanics model is presented to describe the swelling and drug release behavior of hydrogel microneedles. The model integrates the swelling kinetics, the obstruction scaling of drug molecules, and the mechanical properties of hydrogel and skin and reveals the effects of swelling of the microneedle matrix and drug molecules on drug release. Subsequently, numerical simulations were conducted using the model, which enabled the optimization of hydrogel microneedle design parameters by adjusting the input variables. The results show that the geometric parameters of microneedles, especially the cross-sectional shape, have a significant effect on the drug release performance. Nevertheless, the parameters affect each other and need to be considered in the selection of a variety of factors. Additionally, penetration depth significantly affects drug release efficiency, highlighting the need for auxiliary application devices. In summary, the model advances both theoretical understanding and practical design of hydrogel microneedles, identifying key factors in drug release and optimizing their efficiency and reliability for clinical applications. © 2024 Elsevier B.V.

关键词： Drug delivery Finite element simulation Hydrogel microneedles Mathematical model Mechanical property Swelling and obstruction scaling principle

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