检索结果-内蒙古大学图书馆

Mechanical behavior of nanorubber reinforced epoxy over a wide strain rate loading

Nano Materials Science 2024年第1期6卷 106-114页

作者： Yinggang Miao Jianping Yin Wenxuan Du Lianyang Chen Joint International Research Laboratory of Impact Dynamics and Its Engineering Applications School of AeronauticsNorthwestern Polytechnical UniversityXi'anShaanxi710072China State Key Laboratory for Strength and Vibration of Mechanical Structures Xi'an Jiaotong UniversityXi'anShaanxi710049China Shaanxi Key Laboratory of Impact Dynamics and Its Engineering Application School of AeronauticsNorthwestern Polytechnical UniversityXi'anShaanxi710072China

Nanorubber/epoxy composites containing 0,2,6 and 10 wt%nanorubber are subjected to uniaxial compression over a wide range of strain rate from 8×10^(-4) s^(-1) to~2×10^(4) s^(-1).Unexpectedly,their strain rate sensitivity and strain hardening index increase with increasing nanorubber *** mechanisms are proposed based on numerical simulations using a unit cell *** increase in the strain rate sensitivity with increasing nanorubber content results from the fact that the nanorubber becomes less incompressible at high strain,generating a higher hydro-static *** shear localization starts to occur in the epoxy under a strain rate of 22,000 s^(-1) when the strain exceeds *** presence of nanorubber in the epoxy reduces adiabatic shear localization by preventing it from propagating.

关键词： Strain rate Strain hardening Nano rubber Epoxy Adiabatic shearing localization

来源：评论

学校读者我要写书评

暂无评论

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

引用

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

来源：评论

学校读者我要写书评

暂无评论

Effects of Loading Direction and Strain Rate on Mechanical Properties and Failure Modes of Teak 29th

Effects of Loading Direction and Strain Rate on Mechanical P...

引用

29th International Conference on Computational and Experimental engineering and Sciences, ICCES 2023

作者： Yin, Jianping Du, Wenxuan Liu, Lanting Wu, Zhibo He, Xuanfu Miao, Yinggang Shaanxi Key Laboratory of Impact Dynamics and Its Engineering Application School of Aeronautics Northwestern Polytechnical University Shaanxi Xi’an710072 China Joint International Research Laboratory of Impact Dynamics and Its Engineering Applications School of Aeronautics Northwestern Polytechnical University Shaanxi Xi’an710072 China

ISBN: (纸本)9783031425141

The mechanical response and failure mode of wood under compressive load are of great significance for structural design and integrity evaluation. The stress–strain curve of teak with strong impact resistance was investigated by compressive experimenting in the axial, tangential and radial directions under wide strain rates from 10–3 to 103. The results show that their responses behaves similarly and presents a three-stage characteristics in the same loading direction. Teak strength are distinctly directional and strain rate dependent. Deformation processes are monitored by a high-speed camera, which demonstrates that the failure modes consist mainly of fracture, buckling and separation of fiber bundles, crushing, buckling and delamination of the annual ring layer. They are confirmed by the microstructural results. Besides, the failure modes are also affected by the loading direction and strain rate. © 2024, The Author(s), under exclusive license to Springer Nature Switzerland AG.

关键词： Strain rate

来源：评论

学校读者我要写书评

暂无评论

Dynamic flexural strength of Aluminosilicate glass with a perspective of impulsive and quasi-impulsive responses: An experimental-numerical coupled evaluation

引用

Chinese Journal of Aeronautics 2024年第12期37卷 388-403页

作者： Muhammad Aamir RAZA Tao SUO Uzair Ahmed DAR Muhammad ATIF Muhammad Zakir SHEIKH School of Aeronautics and Institute of Extreme Mechanics Northwestern Polytechnical UniversityXi’an 710072China Joint International Research Center of Impact Dynamics and Its Engineering Application Northwestern Polytechnical UniversityXi’an 710072China Shaanxi Key Laboratory of Impact Dynamics and Engineering Application Northwestern Polytechnical UniversityXi’an 710072China National Key Laboratory of Strength and Structural Integrity Northwestern Polytechnical UniversityXi’an 710072China

The flexural strength of glass is a critical design parameter for applications encountering impact ***,the micro defects,specimen geometry,loading rate,and load transformation from a quasi-dynamic to quasi-impulsive state may influence the measurement *** to the stochastic and amorphous nature of the material,an accurate determination of the flexural strength remains a *** this two-fold study,a coupled experimental-numerical strategy was devised to evaluate the dynamic flexural *** the first phase,three-point bending experiments were conducted on a novel“Electromagnetic Split Hopkinson Pressure Bar(ESHPB)”.The incident stress signal and fracture time were recorded from experimental data,while the flexural strength was indirectly computed from a numerical algorithm.A quantitative comparison of the flexural strength with those in existing literature established the accuracy of the proposed *** of the study indicate that the specimen response became independent of the support conditions under impulsive *** being said,the specimen behaved like it had an infinite span length,and the measured flexural strength remained the same whether the specimen was supported or ***,the specimen also maintained contact at the interfaces of the incident bar and fixture supports for the entire loading *** the second part of this study,the computed flexural strength was used to calibrate the existing JH-2 *** prediction of the damage propagation corroborated with that obtained from reprography images,though *** work presents a precise and robust methodology to determine the dynamic flexural strength of brittle ceramics like Aluminosilicate glass over traditional experimental procedures to facilitate its adoption.

关键词： Dynamic flexural strength Damage mechanism Flexural fracture Numerical simulation Aluminosilicate glass

来源：评论

学校读者我要写书评

暂无评论

Biaxial tensile behavior of CoCrFeNi high-entropy alloy under dynamic and proportional loadings

引用

Chinese Journal of Aeronautics 2024年第9期37卷 475-489页

作者： Haoyang LI Liqiang GAO Lin QI Yajing FENG Jingyu WANG Yulong LI Qifeng YU School of Aeronautics.Northwestern Polytechnical University Xiana 710072China Shaanxi Key Laboratory of Impact Dynamics and Engineering Applications Northwestern Polytechnical UniversityXian 710072 China School of Civil Aviation Northwestern Polytechnical UniversitySuzhou 215699China NPU Yangzi River Delta Research Institute Suzhou 215400China

The dynamic failure behavior of CoCrFeNi High-Entropy Alloy(HEA)under plane biaxial stress was investigated in *** dynamic biaxial tensile tests were conducted using an Electromagnetic Biaxial Split Hopkinson Tensile Bar(EBSHTB)*** comparison,the quasi-static uniaxial and biaxial tensile tests,as well as dynamic uniaxial tensile tests,were per-formed respectively.A cruciform specimen suitable for large plastic deformation was designed and employed in the *** Finite Element Method(FEM)verified that the improved cruciform specimen could satisfy the basic *** feasibility of the proposed specimen was further confirmed through loading ***,the quasi-static and dynamic yield loci of the HEA in the first quadrant of the principal stress space were *** results indicate that the alloy exhibits obvious strain hardening effect and strain rate strengthening effect,the yield locus and plastic work contours can be accurately described by Hill'48 criterion.

关键词： High-entropy alloys Biaxial tensile test Cruciform specimen Electromagnetic split Hop-kinson bar Digital image correlation

来源：评论

学校读者我要写书评

暂无评论

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

引用

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

来源：评论

学校读者我要写书评

暂无评论

Structural Integrity Analyses on the Anti-high Overload of a Solid Rocket Motor 29th

Structural Integrity Analyses on the Anti-high Overload of a...

引用

29th International Conference on Computational and Experimental engineering and Sciences, ICCES 2023

作者： Du, Wenxuan Deng, Qiong Tian, Xiaotao Yin, Jianping Hu, Bowen Wang, Yongshuai He, He Miao, Yinggang Shaanxi Key Laboratory of Impact Dynamics and Its Engineering Application School of Aeronautics Northwestern Polytechnical University Shaanxi Xi’an710072 China Joint International Research Laboratory of Impact Dynamics and Its Engineering Applications School of Aeronautics Northwestern Polytechnical University Shaanxi Xi’an710072 China Science and Technology on Combustion and Explosion Laboratory Xi’an Modern Chemistry Research Institute Shaanxi Xi’an710065 China

ISBN: (纸本)9783031425141

Solid propellant works as the most key component for solid rocket motors, and its mechanical behaviors paly a dominant role in the structural integrity of the motor. As typical viscoelastic material, it presents a strong rate-dependence, which would affect the integrity behavior. In the present work, a solid propellant was performed for its constitutive behaviors under wide strain rate loading from 30 to 3000 s−1 using the developed split Hopkinson bar apparatus. A linear viscoelastic constitutive model was then established for carrying out the finite element analysis of an engine structure. As indicated from the simulation results, the possible failure zones in solid rocket motor are revealed, and some stress concentrations localizes in its middle and rear section of the coating layer. Grain failures tend to occur in the concave turning points between the grain rear end and the cushion. The effect of high overload was also analyzed under various cushions, and it was also found that the cushions facilitate the integrity by absorbing energy and confining the deformation of the grain. © 2024, The Author(s), under exclusive license to Springer Nature Switzerland AG.

关键词： Strain rate

来源：评论

学校读者我要写书评

暂无评论

Effects of surface topography and specimen thickness on high-speed raindrop impact damage of CFRP laminates

引用

Chinese Journal of Aeronautics 2023年第6期36卷 186-200页

作者： Naidan HOU Renxi ZHAO Xuan WANG Zhongbin TANG Hao CUI Yulong LI School of Aeronautics Northwestern Polytechnical UniversityXi'an 710072China Joint International Research Laboratory of Impact Dynamics and Engineering Application Xi'an 710072China Shaanxi Key Laboratory of Impact Dynamics and Engineering Application Xi'an 710072China School of Civil Aviation Northwestern Polytechnical UniversitySuzhou 215400China NPU Yangzi River Delta Research Institute Suzhou 215400China

Raindrop impact erosion has been observed since early days of aviation,and can be catastrophic for exposed materials during supersonic flight.A single impact waterjet apparatus is established for mimicking drop impacts at the velocities between 350 m/s and 620 m/*** Fiber Reinforced Polymer(CFRP)laminates with three different surface morphologies and specimen thicknesses are tested here.A central region with no visible damage has been noticed,surrounded by a"failure ring"with common damage patterns including resin removal,matrix cracking,fiber breakage and mass fiber *** features are presented in the"failure ring"whose whole scope extends larger along the longitudinal direction than the transverse direction of the top *** mechanism of the resin removal is related to fiber-matrix debonding,and its onset and propagation can be facilitated by initial surface asperities with the shear action of the lateral *** cases of multiple impact,good surface quality can slow down the evolution of resin removal and fiber exposure on the CFRP surface,reducing the erosion speed and delaying the occurrence of structural damages in the subsequent *** wave dominates the occurrence of matrix cracking on the CFRP surface,and subsequently,results in material loss and peeling of the top-layer because of lateral *** the increase of the specimen thickness,both the interlaminar and intralaminar failures decrease as the impact damage mechanism changes from plate bending stress to the reflection of stress waves.

关键词： Carbon fiber reinforced plastics Failure analysis impact testing Lateral jetting Surface roughness Waterjet

来源：评论

学校读者我要写书评

暂无评论

THE EFFECT OF TARGET THICKNESS ON THE BALLISTICBEHAVIOR OF HYBRID CFRP/KFRP COMPOSITES 34th

THE EFFECT OF TARGET THICKNESS ON THE BALLISTICBEHAVIOR OF H...

引用

34th Congress of the International Council of the Aeronautical Sciences, ICAS 2024

作者： Zhao, Sai Huang, Jia Zhang, Chao School of Civil Aviation Northwestern Polytechnical University Xi’an710072 China Shaanxi Key Laboratory of Impact Dynamics and Its Engineering Applications Northwestern Polytechnical University Xi’an710072 China Key Laboratory of Impact and Safety Engineering Ministry of Education Ningbo University Ningbo Zhejiang315211 China

To achieve structural lightweight and sufficient containment capability, the use of hybrid composite stocivil aircraft engine cases is a major trend. One important but neglected topic was investigated that the thickness effects of hybrid carbon/Kevlar fiber-reinforced epoxy laminates on ballistic impact properties. Based on the results of ballistic impact tests, the finite element models of ballistic impact on carbon/Kevlar hybridlaminates were established using a progressive damage constitutive model, considering different thicknesses, impact faces and layering sequences. The results confirmed an extremely strong relationship between thickness and ballistic impact properties, which has never been addressed in any previous studies of composite stacking methods. Analyses further suggested that the C-K configuration, with CFRP as the impact surface and KFRP as the back surface, exhibits superior impact resistance when the thickness is relatively thin. Conversely, with thicker configurations, the K-C setup, where CFRP serves as the impact surfaceand KFRPas the back surface, demonstrates stronger impact resistance. This study provides theoretical support for the design and development of aero-engine cases. © 2024, International Council of the Aeronautical Sciences. All rights reserved.

关键词： Hybrid composites

来源：评论

学校读者我要写书评

暂无评论

Design and Experimental Study of Raindrop High-Speed Emission System 29th

Design and Experimental Study of Raindrop High-Speed Emissio...

引用

29th International Conference on Computational and Experimental engineering and Sciences, ICCES 2023

作者： Wu, Zhibo Ma, Chengyu Liu, Lanting Yin, Jianping Miao, Yinggang Joint International Research Laboratory of Impact Dynamics and Its Engineering Applications Xi’an China School of Aeronautics Northwestern Polytechnical University Shaanxi Xi’an710072 China

ISBN: (纸本)9783031429866

When aircrafts fly through thunderstorm areas, it is inevitable to suffer the impact of raindrops. The structures may be damaged by the multiple impacts. Therefore, rain erosion test is very important to evaluate the safety and service life of aerospace structures and involved materials. In the work, a multistage system is designed for high-speed raindrop emission based on the split Hopkinson bar technique, and is achieved experimentally. The high-speed camera is used to record the experimental process, and the size and velocity of raindrop are obtained. The results show that the velocity of the raindrop jet increased with the enhancement of loading speed, and the increase is greater than the loading speed. When the velocity of the striker bar is up to 28.22 m/s, the jet velocity can reach 50.90 m/s via acceleration of the emission system. Meanwhile, the raindrop mass is 365.03 mg, and the interval times can be up to more than 5 times. This work could fill the gap of the current high-speed raindrop impact loading technique, and provide the experimental techniques for the anti-raindrop properties of materials and structures from aeronautics and astronautics. © 2024, The Author(s), under exclusive license to Springer Nature Switzerland AG.

关键词： High speed cameras

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：