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

作者： Gu, Jiahui Bai, Yang Zhao, Zhenqiang Zhang, Chao School of Aeronautics Northwestern Polytechnical University Shaanxi Xi’an710072 China School of Civil Aviation Northwestern Polytechnical University Shaanxi Xi’an710072 China Joint International Research Laboratory of Impact Dynamics and Its Engineering Application Shaanxi Xi’an710072 China

Textile composites have been applied widely in aircraft structures, such as fan blades and cases of aero-engine, because of their excellent impact resistance, great delamination resistance and high damage tolerance. Composite fiber tows, as the main load-bearing component, have a critical influence on the dynamic performance of textile composites and even the whole composite structures. However, the determination of the intrinsic properties of individual composite tow mainly relies on theoretical and numerical predictions. In this study, a dynamic compression test method for composite fiber tows is proposed based on the Split Hopkinson pressure bar system combined with an ultra-high-speed camera. Firstly, the porosity contents of composite tows are evaluated and characterized to compare the influence of different preparation methods. A reasonable dumbbell-shaped configuration for the compressive specimen is then proposed, based on the results of both simulated and experimental validation on the stress distribution, the data reduction method, dynamic stress balance, and failure morphology. The preliminary test results show that the compressive properties of composite tows are significantly dependent on the strain rates, and the compressive strength increases by nearly 90% when the strain rate ranges from 0.01 s-1 to 400 s-1. This work will realize the direct and efficient test methodology for determining the dynamic longitudinal compressive performance of composite tows and provide insightful inputs for multiscale analysis of textile composite. © 2024, International Council of the Aeronautical Sciences. All rights reserved.

关键词： Strain rate

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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

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Biaxial tensile behavior of Ti-6Al-4V under proportional loading

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Chinese Journal of Aeronautics 2023年第5期36卷 344-362页

作者： Lin QI Yazhou GUO Kanghua JIN Huaipu KANG Yulong LI School of Aeronautics Northwestern Polytechnical UniversityXi’an 710072China Shaanxi Key Laboratory of Impact Dynamics and Engineering Applications Northwestern Polytechnical UniversityXi’an 710072China School of Civil Aviation Northwestern Polytechnical UniversitySuzhou 215699China NPU Yangzi River Delta Research Institute Suzhou 215400China

The biaxial tensile behavior of isotropic Ti-6Al-4 V is characterized in this paper.A novel cruciform specimen was designed and optimized to achieve uniform stress and strain distribution within the gauge *** tensile tests were conducted at three different loading ratios by the biaxial testing *** Digital Image Correlation(DIC)technique was applied to determine strain distribution,and a high-speed camera was employed to record the fracture *** Inverse Analysis(IA)approach with a combined experimental and numerical method was proposed to determine the true stresses at the gauge section of the specimen during biaxial tensile *** results indicate that the initial yield locus can be described by the Cazacu criterion accurately,whereas the Mises criterion can predict better the strengthening behavior of Ti-6Al-4 V in the first quadrant in the principal stress space.

关键词： Biaxial tensile testing Inverse analysis Strengthening behavior Ti-6Al-4V Yield locus

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

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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

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

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

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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

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加载率、试样尺寸及应力波对钠钙硅酸盐玻璃动态拉伸行为的影响

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Acta Mechanica Sinica 2023年第1期39卷 199-209页

作者：江斌曹俊超郭亚洲李玉龙 School of Aeronautics Northwestern Polytechnical University Xi’an 710072 China Shaanxi Key Laboratory of Impact Dynamics and Engineering Application Northwestern Polytechnical University Xi’an 710072 China School of Civil Aviation Northwestern Polytechnical University Xi’an 710072 China

本文采用平台巴西圆盘(flattened Brazilian disk,FBD)试样研究了加载率、试样尺寸及应力波对钠钙硅酸盐玻璃材料拉伸行为的影响.为此,分别进行了准静态、动态单轴单向(uniaxial unidirectional,UU)和单轴双向(uniaxial bidirectional,... 详细信息

本文采用平台巴西圆盘(flattened Brazilian disk,FBD)试样研究了加载率、试样尺寸及应力波对钠钙硅酸盐玻璃材料拉伸行为的影响.为此,分别进行了准静态、动态单轴单向(uniaxial unidirectional,UU)和单轴双向(uniaxial bidirectional,UB)实验,两种动态实验均是在电磁分离式Hopkinson压杆(electromagnetic split Hopkinson pressure bar,ESHPB)上进行的.实验中采用高速相机对试样的实时变形和断裂过程进行了记录.实验结果显示,虽然在实验加载率范围内,该玻璃的拉伸强度没有显示出明显的率效应,但其强度显著依赖于试样尺寸.此外,动态UU和UB强度差别较小,不同的应力波加载方式对动态拉伸强度的测量影响不大,这与脆性材料动态压缩强度的结论截然不同,通过高速相机记录的断裂过程可以对上述差异进行解释.

关键词：分离式Hopkinson压杆试样尺寸高速相机加载率动态拉伸应力波脆性材料拉伸行为

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在高应变率拉伸/压缩-扭转载荷下TC17钛合金的屈服和塑性流动行为

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Acta Mechanica Sinica 2024年第4期40卷 185-198页

作者：杨学赵敬凡杜冰郭亚洲李玉龙 School of Aeronautics Northwestern Polytechnical University(NPU)Xi’an710072China Yangtze River Delta Research Institute of NPU Taicang215400China Shaanxi Key Laboratory of Impact Dynamics and Engineering Application(IDEA) Northwestern Polytechnical UniversityXi’an710072China

金属材料经常暴露在高应变率和复杂的应力条件下.研究这些材料的动态力学行为对工程设计和工业应用至关重要.本文研究了TC17钛合金在压缩/拉伸-扭转作用下的动态塑性流动行为.研究了TC17钛合金在准静态和动态载荷下的初始屈服行为,并采... 详细信息

金属材料经常暴露在高应变率和复杂的应力条件下.研究这些材料的动态力学行为对工程设计和工业应用至关重要.本文研究了TC17钛合金在压缩/拉伸-扭转作用下的动态塑性流动行为.研究了TC17钛合金在准静态和动态载荷下的初始屈服行为,并采用杨、郭和李提出的动态不对称屈服准则(DAYC)来表征动态初始屈服行为.根据不同应力状态下的硬化特性,提出了一种修正的动态硬化规律(MDHL)来拟合加载面.研究了TC17钛合金在准静态和动态载荷作用下的塑性流动方向.结果表明,塑性势函数基本符合相关联流动法则.总之,本文系统性的研究了TC17钛合金的屈服性能,应变硬化规律和塑性流动规律,并利用DAYC和MDHL对其进行了表征.

关键词： TC17钛合金金属材料塑性流动高应变率扭转载荷动态力学行为应变硬化屈服准则

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A thermal activation based constitutive model for the dynamic deformation of AA5083 processed by large-scale equal-channel angular pressing

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Chinese Journal of Aeronautics 2023年第5期36卷 499-507页

作者： Yunfei WANG Minjie WANG Biao CHEN Huijie SUN Katsuyoshi KONDOH Laszlo JKECSKES Jianghua SHEN School of Aeronautics Northwestern Polytechnical UniversityXi’an 710072China School of Materials Science and Engineering Northwestern Polytechnical UniversityXi’an 710072China Joining and Welding Research Institute Osaka University11-1 MihogaokaOsaka 567-0047Japan Hopkins Extreme Materials Institute Johns Hopkins UniversityBaltimore 21218USA Shaanxi Key Laboratory of Impact Dynamic and Its Engineering Application Xi’an 710072China

Aluminum alloy 5083(AA5083)processed by large-scale Equal-channel angular pressing(ECAP)is an excellent engineering material with great prospects for industrial *** accurate assessment of the underlying constitutive relationships with easily determined material constants is critical for the predictive design and informed processing of such structural *** develop such a design framework,uniaxial dynamic compressive tests over a wide range of temperatures(293-573 K)were carried out for an ECAP-processed AA5083 ***,the microstructure before and after dynamic loading was characterized by SEM and *** on the experimental results,a new dynamic constitutive model,based on thermal activation theory,was established to describe the plastic flow behavior of the AA5083 alloy that incorporates the effects of plastic strain,temperature,and strain *** input parameters of the new model were determined using a particle swarm optimization(PSO)*** model predictions show excellent agreement with experimental results,which suggests that the current predictive constitutive model is highly effective in reproducing the dynamic deformation behavior of the large-scale ECAP-processed AA5083.

关键词： Aluminum alloy 5083(AA5083) Constitutive models Dynamic response Equal channel angular pressing(ECAP) Thermal activation

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Dynamically compressive behaviors and plastic mechanisms of a CrCoNi medium entropy alloy at various temperatures

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Acta Mechanica Sinica 2022年第5期38卷 88-96,I0002页

作者： Kun Jiang Jianguo Li Bin Gan Tian Ye Lianyang Chen Tao Suo School of Aeronautics Northwestern Polytechnical UniversityXi’an 710072China Institute of Extreme Mechanics Northwestern Polytechnical UniversityXi’an 710072China Shaanxi Key Laboratory of Impact Dynamics and its Engineering Application Xi’an 710072China Beijing Key Laboratory of Advanced High Temperature Materials Central Iron and Steel Research InstituteBeijing 100081China

As an attractive class of metallic materials,single-phase CrCoNi medium-entropy alloy(MEA)has drawn much attention recently regarding their deformation behaviors,but the dynamically mechanical responses of this alloy at high strain rates remain less studied,especially coupled with extremely low *** this study,the dynamic deformation behaviors of this CrCoNi MEA were systematically investigated at room temperature(RT)of 298 K and liquid nitrogen temperature(LNT)of 77 K using the split Hopkinson pressure bar(SHPB).This alloy exhibited a combination of higher yield strength and stronger hardening rate upon dynamic compressive deformation when the loading conditions become much harsher(higher strain rate or lower temperature).Detailed microstructure analyses indicated that the strong strain hardening ability during dynamic deformation was mainly attributed to the continuous formation of nanoscale deformation ***,as loaded at LNT,multi-directional deformation twins were ***,due to the interaction between Shockley partial dislocations and twin boundaries,large-sized deformation-induced FCC-HCP phase transformations at a micrometer scale were also observed within the grains,which not only accommodated the plasticity but also played an important role in improving the hardening capability owing to the appearance of newly generated interfaces.

关键词： Medium entropy alloys Extreme loading Dynamically compressive deformation Nanotwins Phase transformation

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A novel videogrammetry-based full-field dynamic deformation monitoring method for variable-sweep wings

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Acta Mechanica Sinica 2024年第8期40卷 120-132页

作者： Liqiang Gao Yan Liu Bin Jiang Zhendong Ge Haoyang Li Xiang Guo Tao Suo Qifeng Yu School of Civil Aviation Northwestern Polytechnical UniversityXi’an710072China Shaanxi Key Laboratory of Impact Dynamics and Engineering Application Northwestern Polytechnical UniversityXi’an710072China College of Physics and Optoelectronic Engineering Shenzhen UniversityShenzhen518060China Institute of Intelligent Optical Measurement and Detection Shenzhen UniversityShenzhen518060China

The measurement of wing dynamic deformation in morphing aircraft is crucial for achieving closed-loop control and evaluating structural *** variable-sweep wings with active large deformation,this paper proposes a novel videogrammetric method for full-field dynamic deformation measurement.A stereo matching method based on epipolar geometry constraint and topological constraint is presented to find the corresponding targets between stereo *** addition,a new method based on affine transformation combined with adjacent closest point matching is developed,aiming to achieve fast and automatic tracking of targets in time-series images with large deformation.A calculation model for dynamic deformation parameters is established to obtain the displacement,sweep variable angle,and span *** verify the proposed method,a dynamic deformation measurement experiment is conducted on a variable-sweep wing *** results indicate that the actual accuracy of the proposed method is approximately 0.02%of the measured area(e.g.,0.32 mm in a 1.6 m scale).During one morphing course,the sweep variable angle,the span variation and the displacement increase gradually,and then *** maximum sweep variable angle is 36.6°,and the span variation is up to 101.13 *** overall configuration of the wing surface is effectively reconstructed under different morphing states.

关键词： Morphing aircraft Variable-sweep wing Videogrammetry Large dynamic deformation Target matching and tracking

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