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A novel subset assignment and matching method for DIC measurement of complex deformation in aircraft braking process

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Chinese Journal of Aeronautics 2024年第8期37卷 373-387页

作者： Xin SHI Xiang GUO Tao SUO Yingtao YUAN Hongli HE Zhiyong REN School of Aeronautics Northwestern Polytechnical UniversityXi’an 710072China international research laboratory of impact dynamics and its engineering application Xi’an 710072China Institute of Extreme Mechanics Northwestern Polytechnical UniversityXi’an 710072China Chinese Flight Test Establishment Xi’an 710089China

This paper proposes a measurement method related to the braking deformation of a complex *** the braking process,the deformation of the wheel includes large amounts of movement,vibration,warping,and distortion.A novel subset assignment and correlation method is proposed to measure the complex *** proposed method can greatly improve the accuracy and stability of the calculation of complex deformations by simplifying the complex deformation into translational deformations in logarithmic coordinate *** to the simulation and actual experiments,the proposed method can be utilized to measure the deformations of up to 100%tensile strain under complex *** to the accuracy verification experiment,the error of the proposed method is less than 50 *** results show that the proposed method can effectively carry out structural deformation measurement in the complex motion and deformation *** proposed method has great significance for structural performance analysis and optimization design considering complex motion and deformation.

关键词： Complex deformation Measurement Digital image correlation Aircraft braking Deformation field

Highly selective and efficient photocatalytic NO removal:Charge carrier kinetics and interface molecular process

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Nano research 2024年第3期17卷 1003-1026页

作者： Huan Shang Hongbao Jia Pengpeng Li Hao Li Wenbin Zhang Shuangjun Li Qing Wang Shuning Xiao Ding Wang Guisheng Li Dieqing Zhang School of Materials and Chemistry University of Shanghai for Science and TechnologyShanghai 200093China The Education Ministry Key Lab of Resource Chemistry Joint International Research Laboratory of Resource Chemistry of Ministry of EducationShanghai Key Laboratory of Rare Earth Functional Materialsand Shanghai Frontiers Science Center of Biomimetic CatalysisShanghai Normal UniversityShanghai 200234China School of Environmental Science and engineering Shanghai Jiao Tong UniversityShanghai 200240China

The widespread nitrogen oxides(NOx,mainly in NO)in the atmosphere have threatened human health and ecological *** dilute NO(ppb)is difficult to efficiently remove via the traditional process due to its characteristics of low concentration,wide range,large total amount,*** can utilize solar energy to purify NO pollutants under mild conditions,but its application is limited due to the low selectivity of nitrate and poor activity of NO *** underlying reason is that the interface mechanism of NO oxidation is not clearly understood,which leads to the inability to accurately regulate the NO oxidation ***,the recent advances in the photocatalytic oxidation of NO are ***,the common strategies to effectively regulate carrier dynamics such as morphology control,facet engineering,defect engineering,plasma coupling,heterojunction and single-atom catalysts are ***,the progress of enhancing the adsorption and activation of reactants such as NO and O_(2) during NO oxidation is described in detail,and the corresponding NO oxidation mechanisms are ***,the challenges and prospects of photocatalytic NO oxidation are presented in term of nanotechnology for air pollution *** review can shed light on the interface mechanism of NO oxidation and provide illuminating information on designing novel catalysts for efficient NOx control.

关键词： nitrogen oxide(NO)oxidation photocatalysis NO/O_(2)activation charge carrier kinetics interfacial mechanism

Size Effect on Onset and Subsequent Evolution of Adiabatic Shear Band:Theoretical and Numerical Analysis

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Acta Mechanica Solida Sinica 2020年第3期33卷 294-306页

作者： Jiejian Liu Tao Suo Fenghua Zhou Yulong Li School of Aeronautics Northwestern Polytechnical UniversityXi’an 710072China Shaanxi Key laboratory of impact dynamics and its engineering application Xi'an 710072China joint international research laboratory of impact dynamics and its engineering application Xi'an 710072China The Faculty of Mechanical engineering and engineering Mechanics Ningbo UniversityNingbo 315211China

The adiabatic shear instability of ductile materials has attracted more and more attentions of researchers and groups,who have been sparing no effort in further understanding of the underlying mechanism since the first experimental depiction of adiabatic shear instability by Zener and *** for the adiabatic shear instability,many factors account for its occurrence,including heat conduction,inertia effect,microstructure effect and so ***,lots of experimental evidence has shown that metal materials display a strong size effect when the characteristic length scale is in the order of *** size effect has also been observed in the analysis of shear band in the ductile materials because the order of the bandwidth stays within the microscale ***,a comprehensive understanding of the whole process of adiabatic shear banding(ASB),including the early onset and the subsequent evolution,is still *** this work,a gradient plasticity model based on the Taylor-based nonlocal theory feasible for the linear perturbation analysis and convenient for numerical calculation is proposed to investigate the strain gradient on the onset of ASB and the coupling effect of heat conduction,inertia effect and strain gradient at the early stage,as well as on the subsequent evolution process at later *** for the onset of ASB,the linear perturbation method is used to consider the effect on the initial formation of *** the investigation of the onset of *** characteristic line method is applied to describe the subsequent nonlinear evolution process of *** stages of ASB evolution are clearly depicted during the evolution process,and the significance of size effect on the ASB nonlinear evolution process of ASB at different stages is *** the help of linear perturbation analysis and characteristic line method,a comprehensive description of the role of strain gradient in the ASB from the early onset to the end of the evolution is provided.

关键词： Adiabatic shear band Strain gradient Nonlinear evolution process Linear perturbation method Characteristic line method

Experimental methods for determination of mechanical behaviors of materials at high temperatures via the split Hopkinson bars

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Acta Mechanica Sinica 2020年第6期36卷 1275-1293,I0003页

作者： Q.B.Dou K.R.Wu T.Suo C.Zhang X.Guo Y.Z.Guo W.G.Guo Y.L.Li School of Aeronautics Northwestern Polytechnical UniversityXi’an710072China joint international research laboratory of impact dynamics and its engineering application Xi’an710072China Shaanxi Key laboratory of impact dynamics and its engineering application Xi’an710072China State Key laboratory for Strength and Vibration of Mechanical Structures School of AerospaceXi’an Jiaotong UniversityXi’an710049China

Full understanding of the thermomechanical behaviors of materials at high strain rates and high temperatures are of great importance from not only scientific meaning but also practical value in engineering structure design and safety *** efforts have been made for abilities of operation the split Hopkinson bars,the most popular technique for experimental determination of mechanical behaviors of materials over the strain rates from 10^2 to 10^4 s^−1 over the past 70 years,at high temperatures since 1960s.A review of experiment work is presented in this paper to give an overview of the development of experimental techniques at high temperatures based on Hopkinson bar *** principles of the split Hopkinson bar requires the loading bars avoiding temperature gradient or keeping relatively low temperature when performing high temperature *** such as performing temperature gradient corrections,rapid heating or using special designed automatically assembled systems were proposed by researchers to enable the operation of the split Hopkinson bars at temperature as high as ***,to the application of high speed photographic technique for capturing the dynamic deformation process of the specimen in high temperature Hopkinson bar testing,some key issues of eliminating the strong thermal radiation induced lights oversaturation and de-blurring of images due to insufficient exposure at high temperature and high strain rate condition,as well as fabrication of high contrast speckle pattern for high temperature digital image correlation measurement were also *** technique can now enable the split Hopkinson bar testing to be performed at high temperature up to 1873 K under the loading conditions of compression or tension with the in situ observation and full field measurement of deformation as *** paper concludes with summaries of the most important achievements and highlighting of the prospects,trends and remaining challenge

关键词： Mechanical behaviors Split Hopkinson bar High strain rate High temperature

Molecular dynamics study on mechanical behaviors of Ti/Ni nanolaminate with a pre-existing void

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Nano Materials Science 2022年第2期4卷 113-125页

作者： Mengjia Su Qiong Deng Lanting Liu Lianyang Chen He He Yinggang Miao joint international research laboratory of impact dynamics and its engineering applications School of AeronauticsNorthwestern Polytechnical UniversityXi'anShaanxi 710072China

Metallic nanolaminated materials possess excellent mechanical properties due to their unique modulation structures and interfacial ***,how microdefects affect their mechanical properties is still *** evaluate the influences of void location(in the crystalline layer and the Ti/Ni interface),void diameter(d)and thickness of the intermediate layer(h)on overall tensile behaviors,various types of defective Ti/Ni nanolaminates with pre-existing void are established by the molecular dynamics method in this *** results indicate that the strength and plastic deformation mechanisms are strongly dependent on those *** stresses of Ti/Ni nanolaminates decrease distinctly with increasing void diameter,while peak stresses with a void in the crystalline layer decrease with increasing d/*** void locations lead eventually to disparate initial plastic deformation carriers around the void,and various evolutions in the microstructure of the defective Ti/Ni *** Ti/Ni interface plays a significant role in the tensile *** semi-coherent interface impedes new grains and lattice dislocations from passing across the interface,while the incoherent interface facilitates dislocations generating and sliding along the interface,and absorbs the dislocations moving to the *** results also indicate that the strain rate significantly affects the evolution of the microstructure and the tensile properties of defective Ti/Ni nanolaminates.

关键词： Defective Ti/Ni nanolaminate Pre-existing void Interface Tensile behaviors Molecular dynamics

Development of multi-functional anchorage support dynamic-static coupling performance test system and its application

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international Journal of Mining Science and Technology 2024年第3期34卷 339-349页

作者： Qi Wang Shuo Xu Bei Jiang Chong Zhang Zhe Sun Jingxuan Liu Cailin Jiao State Key laboratory for Tunnel engineering China University of Mining&Technology-BeijingBeijing 100083China research Center of Geotechnical and Structural engineering Shandong UniversityJinan 250061China

In underground engineering with complex conditions,the bolt(cable)anchorage support system is in an environment where static and dynamic stresses coexist,under the action of geological conditions such as high stresses and strong disturbances and construction conditions such as the application of high *** is essential to study the support components performance under dynamic-static coupling *** on this,a multi-functional anchorage support dynamic-static coupling performance test system(MAC system)is developed,which can achieve 7 types of testing functions,including single component performance,anchored net performance,anchored rock performance and so *** bolt and cable mechanical tests are conducted by MAC system under different prestress *** results showed that compared to the non-prestress condition,the impact resistance performance of prestressed bolts(cables)is significantly *** the prestress range of 50–160 k N,the maximum reduction rate of impact energy resisted by different types of bolts is 53.9%–61.5%compared to non-prestress *** the prestress range of 150–300 k N,the impact energy resisted by high-strength cable is reduced by76.8%–84.6%compared to non-prestress *** MAC system achieves dynamic-static coupling performance test,which provide an effective means for the design of anchorage support system.

关键词： Anchorage support system Development of test system Dynamic-static coupling test Combined stress

Gradient structure induced simultaneous enhancement of strength and ductility in AZ31 Mg alloy with twin-twin interactions

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Journal of Magnesium and Alloys 2023年第8期11卷 2872-2882页

作者： Qinghui Zhang Jianguo Li Kun Jiang Pu Li Yusheng Li Yong Zhang Tao Suo School of Aeronautics Northwestern Polytechnical UniversityXi'an 710072China Shaanxi Key laboratory of impact dynamics and its engineering application Xi'an 710072China joint international research laboratory of impact dynamics and its engineering application Xi'an 710072China School of Materials Science and engineering Nanjing University of Science and TechnologyNanjing 210094China School of Materials Science and engineering Herbert Gleiter Institute of NanoscienceNanjing University of Science and TechnologyNanjing 210094China

Gradient nanostructure was introduced to enhance the strength and ductility via deformation incompatibility accommodated by geometrical necessary dislocations for most metallic materials ***,few intensive researches were carried out to investigate the effect of gradient structure on the deformation twin evolution and resulting performance *** the present paper,we produced gradient-structured AZ31 Mg alloy with fine-grain layers,parallel twin laminates and a coarse-grain core from two upmost surfaces to the center of ***,this architected Mg alloy exhibited simultaneous enhancement of strength and *** microstructural observations demonstrated that abundant twin-twin interactions resulting from higher strength and multi-axial stress state could make great contributions to the increase of work-hardening *** was further proved by the measurement of full-field strain evolution during the plastic *** a design strategy may provide a new path for producing advanced structure materials in which the deformation twinning works as one of the dominant plasticity mechanisms.

关键词： Mg alloy Gradient structure Strength-ductility synergy Multi-orientational twins Twin-twin interactions

Energy dissipation mechanism and ballistic characteristic optimization in foam sandwich panels against spherical projectile impact

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Defence Technology（防务技术） 2024年第5期35卷 108-122页

作者： Jianqiang Deng Tao Liu Liming Chen Xin Pan Jingzhe Wang Shaowei Zhu Weiguo Li College of Aerospace engineering Chongqing UniversityChongqing 400030China State Key laboratory of Coal Mine Disaster dynamics and Control Chongqing UniversityChongqing 400030China Chongqing Key laboratory of Heterogeneous Material Mechanics Chongqing UniversityChongqing 400030China State Key laboratory of Explosion Science and Technology Beijing Institute of TechnologyBeijing 100081China

This study systematically examines the energy dissipation mechanisms and ballistic characteristics of foam sandwich panels(FSP)under high-velocity impact using the explicit non-linear finite element *** on the geometric topology of the FSP system,three FSP configurations with the same areal density are derived,namely multi-layer,gradient core and asymmetric face sheet,and three key structural parameters are identified:core thickness(t_(c)),face sheet thickness(t_(f))and overlap face/core number(n_(o)).The ballistic performance of the FSP system is comprehensively evaluated in terms of the ballistic limit velocity(BLV),deformation modes,energy dissipation mechanism,and specific penetration energy(SPE).The results show that the FSP system exhibits a significant configuration dependence,whose ballistic performance ranking is:asymmetric face sheet>gradient core>*** mass distribution of the top and bottom face sheets plays a critical role in the ballistic resistance of the FSP *** BLV and SPE increase with tf,while the raising tcor noleads to an increase in BLV but a decrease in ***,a face-core synchronous enhancement mechanism is discovered by the energy dissipation analysis,based on which the ballistic optimization procedure is also conducted and a design chart is *** study shed light on the anti-penetration mechanism of the FSP system and might provide a theoretical basis for its engineering application.

关键词： Sandwich panel Numerical simulation Ballistic resistance Specific penetration energy Energy analysis

Cross-linked polyelectrolyte reinforced SnO_(2)electron transport layer for robust flexible perovskite solar cells

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Journal of Energy Chemistry 2023年第10期85卷 335-342,I0010页

作者： Zhihao Li Zhi Wan Chunmei Jia Meng Zhang Meihe Zhang Jiayi Xue Jianghua Shen Can Li Chao Zhang Zhen Li State Key laboratory of Solidification Processing Center for Nano Energy MaterialsSchool of Materials Science and EngineeringNorthwestern Polytechnical University and Shaanxi Joint Laboratory of Graphene(NPU)Xi’an 710072ShaanxiChina Department of Aeronautical Structure engineering School of AeronauticsNorthwestern Polytechnical UniversityXi’an 710072ShaanxiChina Shaanxi Key laboratory of impact dynamics and its engineering application Joint International Research Laboratory of Impact Dynamics and Its Engineering ApplicationsXi’an 710072ShaanxiChina research&Development Institute of Northwestern Polytechnical University in Shenzhen Shenzhen 519057GuangdongChina

SnO_(2)electron transport layer(ETL)is a vital component in perovskite solar cells(PSCs),due to its excellent photoelectric properties and facile fabrication *** this study,we synthesized a water-soluble and adhesive polyelectrolyte with ethanolamine(EA)and poly-acrylic acid(PAA).The linear PAA was crosslinked by EA,forming a 3D network that stabilized the SnO_(2)nanoparticle *** organic–inorganic hybrid ETL is developed by introducing the cross-linked PAA-EA into SnO_(2)ETL,which prevents nano particle agglomeration and facilitates uniform SnO_(2)film formation with fewer ***,the PAA-EA-modified SnO_(2)facilitated a uniform and compact perovskite film,enhancing the interface contact and carrier ***,the PAA-EA-modified PSCs exhibited excellent PCE of 24.34%and 22.88%with high reproducibility for areas of 0.045 and 1.00 cm~2,***,owing to structure reinforce effect of PAA-EA in SnO_(2)ETL,flexible device demonstrated an impressive PCE of 23.34%while maintaining 90.1%of the initial PCE after 10,000 bending cycles with a bending radius of 5 *** successful approach of polyelectrolyte reinforced hybrid organic–inorganic ETL displays great potential for flexible,large-area PSCs application.

关键词： Polyelectrolyte Cross-link Tin oxide Electron transfer layer Flexible solar cells