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A High-Accuracy Curve Boundary Recognition Method Based on the Lattice Boltzmann Method and Immersed Moving Boundary Method

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Computer Modeling in Engineering & Sciences 2024年第9期140卷 2533-2557页

作者： Jie-Di Weng Yong-Zheng Jiang Long-Chao Chen Xu Zhang Guan-Yong Zhang hunan Provincial key laboratory of health maintenance for mechanical equipment Hunan University of Science and TechnologyXiangtan411201China School of mechanical Engineering Hunan Chemical Vocational Technology CollegeZhuzhou412000China

Applying numerical simulation technology to investigate fluid-solid interaction involving complex curved bound-aries is vital in aircraft design,ocean,and construction ***,current methods such as Lattice Boltzmann(LBM)and the immersion boundary method based on solid ratio(IMB)have limitations in identifying custom curved ***,IBM based on velocity correction(IBM-VC)suffers from inaccuracies and numerical ***,this study introduces a high-accuracy curve boundary recognition method(IMB-CB),which identifies boundary nodes by moving the search box,and corrects the weighting function in LBM by calculating the solid ratio of the boundary nodes,achieving accurate recognition of custom curve *** addition,curve boundary image and dot methods are utilized to verify *** findings revealed that IMB-CB can accurately identify the boundary,showing an error of less than 1.8%with 500 ***,the flow in the custom curve boundary and aerodynamic characteristics of the NACA0012 airfoil are calculated and compared to *** showed that IMB-CB yields lower lift and drag coefficient errors than IBM-VC,with a 1.45%drag coefficient *** addition,the characteristic curve of IMB-CB is very stable,whereas that of IBM-VC is *** the moving boundary problem,LBM-IMB-CB with discrete element method(DEM)is capable of accurately simulating the physical phenomena of multi-moving particle flow in complex curved *** research proposes a new curve boundary recognition method,which can significantly promote the stability and accuracy of fluid-solid interaction simulations and thus has huge applications in engineering.

关键词： Fluid-solid interaction curve boundary recognition method Lattice Boltzmann method immersed moving boundary method

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Study on cumulative effects of biological craniocerebral trauma under repeated blast

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Theoretical & Applied Mechanics Letters 2024年第3期14卷 174-183页

作者： Xingyuan Huang Bingchen Xia Lijun Chang Zhikang Liao Hui Zhao Zhihua Cai hunan Provincial key laboratory of health maintenance for mechanical equipment Hunan University of Science and TechnologyXiangtan 411201China School of mechanical and Electrical Engineering Foshan UniversityFoshan 528231China Institute for Traffic Medicine PLA Army Characteristic Medical CenterChongqing 400042China

Repeated blast impacts on personnel in explosive environments can exacerbate craniocerebral *** existing studies focus on the injury effects of a single blast,lacking in-depth analysis on the injury effects and cumulative effects of repeated ***,rats were used as the experimental samples to suffer from explosion blasts with different peak air overpressures(167 kPa~482 kPa)and varying number of repeated *** cumulative effect of craniocerebral trauma was most pronounced for moderate repeated blast,showing approximately 95%increase of trauma severity with penta blast,and an approximately 85%increase of trauma severity with penta minor *** cumulative effect of craniocerebral trauma from severe,repeated blast has a smaller rate of change compared to the other two *** severity of trauma from penta blast increased by approximately 69%compared to a single *** physiological,pathological and biochemical analysis show that the degree of neurological trauma caused by repeated blasts is higher than that of single blasts,and the pathological trauma to brain tissue is more extensive and *** trauma degree remains unchanged after double blast,increases by one grade after triple or quadruple blast,and increases by two grades after penta blast.

关键词： Repeated blast Craniocerebral trauma Trauma severity grade Cumulative effects

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Toughened (Ti_(0.2)Zr_(0.2)Hf_(0.2)Nb_(0.2)Ta_(0.2))B_(2)–SiC composites fabricated by one-step reactive sintering with a unique SiB_(6) additive

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Journal of Advanced Ceramics 2024年第1期13卷 86-100页

作者： Wei Hao Xinzhe Lu Ling Li Tao Wang Guoliang Ren Huangyue Cai Xiaofeng Zhao Dongyun Wang Na Ni Zhejiang Provincial key laboratory of Urban Rail Transit Intelligent Operation and maintenance Technology&equipment Zhejiang Normal UniversityZhejiang 321004China key lab of Education Ministry for Power Machinery and Engineering School of Mechanical EngineeringShanghai Jiao Tong UniversityShanghai 200240China School of Materials Science and Engineering Shanghai Jiao Tong UniversityShanghai 200240China

High-entropy diboride has been arousing considerable interest in recent ***,the low toughness and damage tolerance limit its applications as ultra-high-temperature structural *** we report that a unique SiB_(6) additive has been first incorporated as boron and silicon sources to fabricate a high-entropy boride(Ti_(0.2)Zr_(0.2)Hf_(0.2)Nb_(0.2)Ta_(0.2))B_(2)–SiC composite though one-step boro/carbothermal reduction reactive sintering.A synergetic effect of high-entropy sluggish diffusion and SiC secondary phase retarded the grain growth of the(Ti_(0.2)Zr_(0.2)Hf_(0.2)Nb_(0.2)Ta_(0.2))B_(2)–51SiC *** small grain size was beneficial to shorten the diffusion path for mass transport,thereby enhancing the relative density to~99.3%.These results in an increase of fracture toughness from~5.2 in HEBS-1900 to~7.7 MPa·m^(1/2) in HEBS-2000,which corresponded to a large improvement of 48%.The improvement was attributed to a mixed mode of intergranular and transgranular cracking for offering effective pinning in crack propagation,resulting from balanced grain boundary strength collectively affected by improved densification,solid solution strengthening,and incorporation of SiC secondary phase.

关键词： high-entropy diboride silicon hexaboride boro/carbothermal reduction reactive sintering fracture toughness

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Experimental Analysis of Radial Centrifugal Pump Shutdown

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Fluid Dynamics & Materials Processing 2024年第4期20卷 725-737页

作者： Xiao Sun Jiangbo Tong Yuliang Zhang Haibing Cai Wen Zhou Xiaoqi Jia Litao Ou School of mechanical Engineering Hunan University of TechnologyZhuzhou412007China College of mechanical Engineering Quzhou UniversityQuzhou324000China Zhejiang Testing&Inspection Institute for mechanical and Electrical Products Quality Co. Ltd.Hangzhou310014China Quzhou Special equipment Inspection Center Quzhou324000China The Zhejiang Provincial key lab of Fluid Transmission Technology Zhejiang Sci-Tech UniversityHangzhou310018China Zhuzhou Nanfang Valve Co. Ltd.Zhuzhou412000China

Centrifugal pumps are widely used in the metallurgy,coal,and building *** order to study the hydraulic characteristics of a closed impeller centrifugal pump during its shutdown in the so-called power frequency and frequency conversion modes,experiments were carried to determine the characteristic evolution of parameters such as speed,inlet and outlet pressure,head,flow rate and shaft power.A quasi-steady-state method was also used to further investigate these transient *** results show that,compared to the power frequency input,the performance parameter curves for the frequency conversion input are less volatile and *** characteristic time is longer and the response to shutdown is *** quasi-steady-state theoretical head-flow curves match the experimental head-flow curves more closely at low flow rates when the frequency conversion input is ***,in this case,the similarity law predicts the hydraulic performance more accurately.

关键词： Centrifugal pump power frequency frequency conversion shutdown external characteristic experimental study

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Investigation of mechanical failure performance of a large-diameter shield tunnel segmental ring

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2024年第5期25卷 411-428页

作者： Binyong GAO Renpeng CHEN Huaina WU Chengcheng ZHANG Meng FAN Chao XIAO Research Center of Underground Space Advanced Technology Hunan UniversityChangsha 410082China key laboratory of Building Safety and Energy Efficiency of the Ministry of Education Hunan UniversityChangsha 410082China Department of Civil Engineering Hunan UniversityChangsha 410082China China Construction No.5 Civil Engineering Co. Ltd.Changsha 410004China

The control criteria for structural deformation and the evaluation of operational safety performance for large-diameter shield tunnel segments are not yet clearly *** address this issue,a refined 3D finite element model was established to analyze the transverse deformation response of a large-diameter segmental *** analyzing the stress,deformation,and crack distribution of large-diameter segments under overload conditions,the transverse deformation of the segmental ring could be divided into four *** main reasons for the decrease in segmental ring stiffness were found to be the extensive development of cracks and the complete formation of four plastic *** deformation control value for the large-diameter shield tunnel segment is chosen as 8%o of the segment's outer diameter,representing the transverse deformation during the formation of the first semi-plastic hinge(i.e.,the first yield point)in the *** control value can serve as a reinforcement standard for preventing the failure of large-diameter shield tunnel *** flexural bearing capacity characteristic curve of segments was used to evaluate the structural strength of a large-diameter segmental *** was discovered that the maximum internal force combination of the segment did not exceed the segment ultimate bearing capacity curve(SUBC).However,the combination of internal force at 9°,85°,and 161°of the joints,and their symmetrical locations about the 0°-180°axis exceeded the joint ultimate bearing capacity curve(JUBC).The results indicate that the failure of the large-diameter segment lining was mainly due to insufficient joint strength,leading to an instability *** findings from this study can be used to develop more effective maintenance strategies for large-diameter shield tunnel segments to ensure their long-term performance.

关键词： Finite element model Transverse deformation response Upper overload Plastic hinges Flexural bearing capacity

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Study of Impact Resistance Based on Porcupine Quills Bionic Thin-walled Structure

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Journal of Bionic Engineering 2023年第5期20卷 1942-1955页

作者： Tianshu Huang Zhengyu Mao Lijun Chang Xingyuan Huang Zhihua Cai hunan Provincial key laboratory of health maintenance for mechanical equipment Hunan University of Science and TechnologyXiangtanChina School of mechanical Engineering Hunan University of Science and TechnologyXiangtanChina

Using an electron microscope to observe the microstructure of a porcupine quills cross-section and a bionic method,a new bionic structure was *** performance of the structure in terms of energy absorption,maximum impact force withstood,and impact force efficiency was evaluated using Ansys finite element simulation software to simulate the structure's *** examine the impact of ribs on the structural performance of the bionic porcupine quills,a control structure was *** to the results of the finite element simulation,the presence of ribs in the Bionic porcupine quills structure can transfer stress uniformly to the overall structure and share stress for some of the rupture-prone *** reduce stress concentration in specific areas and increase the impact force efficiency of the *** SEA and IFE values of bionic porcupine quills were 30.01 kJ/kg and 84.22%,*** structure is then optimized for parameter design in order to find the optimal structure by response surface in order to improve the structure's SEA and decrease its *** order to evaluate the precision of the response surface,the optimal structure predicted is validated using finite element simulation.

关键词： Bionic structure design Thin-walled structure Impact resistance Specific energy absorption Multi-objective optimization

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High-precision nondestructive evaluation of a thermal barrier coating based on perovskite quantum dot anion exchange

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Nano Research 2024年第5期17卷 4582-4592页

作者： Tao Han Shufang Ding Zifan Wang Sirong Jiang Pengjiang Jing Tianshang Yi Yaqi Chen Chunzhi Jiang Xiaofeng Zhang Microelectronics and Optoelectronics Technology key laboratory of hunan Higher Education School of Physics and Electronic Electrical EngineeringXiangnan UniversityChenzhou 423000China National Engineering laboratory for Modern Materials Surface Engineering Technology&The key lab of Guangdong for Modern Surface Engineering Technology Guangdong Institute of New MaterialsGuangdong Academy of SciencesGuangzhou 510650China

Thermal barrier coatings(TBCs)in gas turbine engines are used in expressly harsh environments;thus,assessing TBC integrity status is critical for safety and ***,traditional periodic maintenance involves visual inspections of the TBCs,requiring the gas turbine to be decommissioned and partially *** importantly,tiny defects or internal damages that easily cause coating failure cannot be *** this work,a new nondestructive evaluation(NDE)technique of TBCs based on quantum dot(QD)anion exchange is first explored *** exchanging anions between the Cl ions and the CsPbBr_(3) QDs,the degrees of salt corrosion of the TBCs are *** resultant NDE technique shows that the colour of the TBCs obviously changes from green to blue,accompanied by a large blueshift(~100 nm)of the photoluminescence(PL)peak *** addition,the relationship between the PL peak position and coating thermophysical properties indicates that the precision of this NDE technique may easily identify theμm-level of the thermal growth oxide(TGO)changes inside the TBCs.

关键词： thermal barrier coatings nondestructive evaluation CsPbBr_(3)quantum dot anion exchange thermal growth oxide

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Construction of MnS/MoS_(2) heterostructure on two-dimensional MoS_(2) surface to regulate the reaction pathways for high-performance Li-O_(2) batteries

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Journal of Energy Chemistry 2024年第6期93卷 443-452,I0012页

作者： Guoliang Zhang Han Yu Xia Li Xiuqi Zhang Chuanxin Hou Shuhui Sun Yong Du Zhanhu Guo Feng Dang key laboratory for Liquid-Solid Structure Evolution and.Processing of Materials(Ministry of Education) Shandong UniversityJinan 250061ShandongChina School of Environmental and Material Engineering Yantai UniversityYantai 264005ShandongChina Institute National de la Recherche Scientifique CentreÉnergie Matériaux et TélécommunicationsVarennesQuébec J31S2Canada State key laboratory of Powder Metallurgy Central South UniversityChangsha 410083HunanChina Integrated Composites lab Department of Mechanical and Construction EngineeringNorthumbria UniversityNewcastle Upon TyneNE18STUK

The inherent catalytic anisotropy of two-dimensional(2D) materials has limited the enhancement of LiO_(2) batteries(LOBs) performance due to the significantly different adsorption energies on 2D and edge *** the adsorption strength in 2D materials to the reaction intermediates is essential for achieving high-performance ***,a MnS/MoS_(2) heterostructure is designed as a cathode catalyst by adjusting the adsorption behavior at the *** from the toroidal-like discharge products on the MoS_(2) cathode,the MnS/MoS_(2) surface displays an improved adsorption energy to reaction species,thereby promoting the growth of the film-like discharge *** can disturb the layer growth of MoS_(2),in which the stack edge plane features a strong interaction with the intermediates and limits the growth of the discharge *** and theoretical results confirm that the MnS/MoS_(2) heterostructure possesses improved electron transfer kinetics at the interface and plays an important role in the adsorption process for reaction species,which finally affects the morphology of Li_2O_(2),In consequence,the MnS/MoS_(2) heterostructure exhibits a high specific capacity of 11696.0 mA h g^(-1) and good cycle stability over 1800 h with a fixed specific capacity of 600 mA h g^(-1) at current density of100 mA g^(-1) This work provides a novel interfacial engineering strategy to enhance the performance of LOBs by tuning the adsorption properties of 2D materials.

关键词： Li-O_(2)batteries Two-dimensional materials MnS/MoS_(2)heterostructure Edge plane Adsorption behavior

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Spin transport of half-metal Mn_(2)X_(3) with high Curie temperature:An ideal giant magnetoresistance device from electrical and thermal drives

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Frontiers of physics 2024年第4期19卷 125-135页

作者： Bin Liu Xiaolin Zhang Jingxian Xiong Xiuyang Pang Sheng Liu Zixin Yang Qiang Yu Honggen Li Sicong Zhu Jian Wu Hubei province key laboratory of Systems Science in Metallurgical Process The State Key Laboratory for Refractories and MetallurgyCollaborative Innovation Center for Advanced SteelsInternational Research Institute for Steel TechnologyWuhan University of Science and TechnologyWuhan 430081China key laboratory of Artificial Micro-and Nano-structures of Ministry of Education and School of Physical and Technology Wuhan UniversityWuhan 430072China College of Advanced Interdisciplinary Studies Nanhu Laser LaboratoryNational University of Defense TechnologyChangsha 410073China Department of mechanical Engineering National University of SingaporeSingapore 117575Singapore i-lab&key laboratory of Nanodevices and Applications&key laboratory of Nanophotonic Materials and Devices Suzhou Institute of Nano-Tech and NanoBionicsChinese Academy of SciencesSuzhou 215123China Institute of Optical Science and Technology School of Physics and AstronomyShanghai Jiao Tong UniversityShanghai 200240China

Currently,magnetic storage devices are encountering the problem of achieving lightweight and high integration in mobile computing devices during the information *** a result,there is a growing urgency for twodimensional half-metallic materials with a high Curie temperature(TC).This study presents a theoretical investigation of the fundamental electromagnetic properties of the monolayer hexagonal lattice of Mn_(2)X_(3)(X=S,Se,Te).Additionally,the potential application of Mn_(2)X_(3) as magneto-resistive components is *** three of them fall into the category of ferromagnetic *** particular,the Monte Carlo simulations indicate that the TC of Mn2S3 reachs 381 K,noticeably greater than room *** findings present notable advantages for the application of Mn2S3 in spintronic ***,a prominent spin filtering effect is apparent when employing non-equilibrium Green’s function simulations to examine the transport *** resulting current magnitude is approximately 2×10^(4) nA,while the peak gigantic magnetoresistance exhibits a substantial value of 8.36×10^(16)%.It is noteworthy that the device demonstrates a substantial spin Seebeck effect when the temperature differential between the electrodes is *** brief,Mn_(2)X_(3) exhibits outstanding features as a highTC half-metal,exhibiting exceptional capabilities in electrical and thermal drives spin ***,it holds great potential for usage in spintronics applications.

关键词： half-metals Mn_(2)X_(3) high Curie temperature electrical and thermal GMR

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Effects of Unbalance Location on Dynamic Characteristics of High-speed Gasoline Engine Turbocharger with Floating Ring Bearings

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Chinese Journal of mechanical Engineering 2016年第2期29卷 271-280页

作者： WANG Longkai BIN Guangfu LI Xuejun LIU Dingqu health maintenance for mechanical equipment key lab of hunan province Hunan University of Science and Technology

For the high-speed gasoline engine turbocharger rotor, due to the heterogeneity of multiple parts material, manufacturing and assembly errors, running wear in impeller and uneven carbon of turbine, the random unbalance usually can be developed which will induce excessive rotor vibration, and even lead to nonlinear vibration accidents. However, the investigation of unbalance location on the nonlinear high-speed turbocharger rotordynamic characteristics is less. In order to discuss the rotor unbalance location effects of turbocharger with nonlinear floating ring bearings（FRBs）, the realistic turbocharger of gasoline engine is taken as a research object. The rotordynamic equations of motion under the condition of unbalance are derived by applied unbalance force and nonlinear oil film force of FRBs. The FE model of turbocharger rotor-bearing system is modeled which includes the unbalance excitation and nonlinear FRBs. Under the conditions of four different applied locations of unbalance, the nonlinear transient analyses are performed based on the rotor FEM. The differences of dynamic behavior are obvious to the turbocharger rotor systems for four conditions, and the bifurcation phenomena are different. From the results of waterfall and transient response analysis, the speed for the appearance of fractional frequency is not identical and the amplitude magnitude is different from the different unbalance locations, and the non-synchronous vibration does not occur in the turbocharger and the amplitude is relative stable and minimum under the condition 4. The turbocharger vibration and non-synchronous components could be reduced or suppressed by controlling the applied location of unbalance, which is helpful for the dynamic design, fault diagnosis and vibration control of the high-speed gasoline engine turbochargers.

关键词： high-speed turbocharger unbalance location nonlinear transient analysis waterfall dynamic characteristics

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