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A STUDy OF RATE-DEPENDENCE AT ELEVATED TEMPERATURE FOR AN Al-Cu-Mg ALLOy

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Acta Metallurgica Sinica(English Letters) 2004年第4期17卷 618-624页

作者： y.q.wu H.J.Shi K.S.Zhang Key Laboratory of Failure Mechanics Department of Engineering Mechanics Tsinghua UniversityBeijing 100084 China Department of Engineering Mechanics North-Western Polytechnical University Xi'an 710072 ChinaKey Laboratory of Failure Mechanics Department of Engineering Mechanics Tsinghua UniversityBeijing 100084 ChinaDepartment of Engineering Mechanics North-Western Polytechnical University Xi'an 710072 China

The hot deformation of an Al-Cu-Mg alloy was studied in the two temperature ranges (room temperature-300℃ and 400℃-480℃). The rate-independent flow curves are typical of elasto-plastic response with significant work hardening followed by strain softening below 300℃. Similar dislocation structures with high density tangled into grain interiors were observed by TEM, which suggests that the process of obstacles arresting mobile dislocations results in this macroscopically rate-independence. At 400-480℃, all rate dependent flow behaviors characterized by a continuous softening after an initial work hardening at a small plastic strain show large tensile elongations. Long dislocation segments around the second phases infer their good mobility to climb across obstacles. Grain boundary morphology observed by TEM suggests that the capacity of the grain boundaries to absorb the dislocations sensitively accounts for the rate-dependent mechanical properties.

关键词： rate dependence elevated temperature dislocations,grain boundary

LOW CyCLE FATIGUE AND DEFORMATION BEHAVIOR IN AN 8090 Al-Li ALLOy

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Acta Metallurgica Sinica(English Letters) 1998年第1期11卷 1-11页

作者： S.H.Ai y.q.wu Z.G.Wang y.Zhang Chinese Acad of Sciences Shenyang China

Low cycle fatigue (LCF)tests under different total strain amplitudes have been conducted in order to ascertain the effect of precipitate sizes on LCF behavior of 8090 Al-Li alloy. A constant strain rate of 3×10-3s-1 and symmetrical triangular waveform were employed for all tests. It is found that the cyclic stress response of the alloy varied with the precipitate sizes and strain amplitudes. The materials in all conditions cyclically handen at first and the higher the strain amplitude, the greater the amount of hardening. The low cyclic flow stress is the highest in the peakaged condition. TEM and SEM observations demonstrated that cyclic stress-strain behavior and fracture mode of Al-Li alloy are closely related to an increase in the dislocation density and interaction between the precipitates and dislocations, sizes of δ particles and pricipitate free zone (PFZ) at grain boundaries.

关键词： Al-Li alloy low cycle fatigue aged condition

Ergonomics Design Research of an Office Desks and Chairs Based on CAD

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Ergonomics Design Research of an Office Desks and Chairs Bas...

Hydrogenation mechanism in lanthanum-activated magnesium films:a density functional theory study

International Conference on Industrial Technology and Management Science(ITMS 2015)

作者： L.A.Pan q.L.Du y.q.wu College of Mechanical and Vehicle Engineering Changchun University Naval Aeronautical Engineering Institute

Office leisure is the common pursuit of the enterprise, government, leadership and staff. The relaxed, happy, free and comfortable life is people always wish, also is inevitable to era development and social progress. So, according to the demand, indoor and outdoor dual-use multi-function folding leisure office furniture has been designed in the paper. First of all, through a large number of research and decisions, the structure of the product portfolio has been determined. In order to be convenient and quick, the characteristics of the furniture on the market have been collected and analyzed, especially the table, chairs and a bed. According to ergonomics, the parameters of the outdoor leisure office desks and chairs have been determined. The rhino software has been used to establish the combination of desk and chair to make the products comply with ergonomics, human psychology and aesthetic principles of the product.

关键词： Office desks and chairs CAD Ergonomics 3D Max

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Hydrogenation mechanism in lanthanum-activated magnesium fil...

评估乳腺瘤周区域MRI特征与乳腺癌预后的关系：系统性回顾和荟萃分析

第九届全国氢能学术会议

作者： G.X.wu~1,J.y.Zhang~1,y.q.wu~1,q.Li~1,K.C.Chou~(1,2),X.H.Bao~1 ~1 Shanghai University,China ~2University of Science and Technology Beijing,China

A small amount of transition metal-oxide catalysts,such as NbO,FeO and VO,are known to substantially improve the adsorption and desorption thermodynamics and kinetics of Mg-based ***,it has been also demonstrated that alloying magnesium with rare-earth metal-oxide,such as LaO,is beneficial in goveming the high hydrogen content

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国际医学放射学杂志 2024年第6期 747页

作者： S.q.Zhao y.F.Li N.Ning H.B.Liang y.q.wu q.wu 李响

摘要目的评估瘤周区域MRI特征与乳腺癌预后之间的关系。方法对截至2022年10月发表的观察性研究进行了回顾性荟萃分析，对预后不良的乳腺癌病人和对照组的瘤

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Interface defeat studies of long-rod projectile impacting on ceramic targets

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Defence Technology（防务技术） 2020年第1期16卷 50-68页

作者： y.X.Zhai H.wu q.Fang Amy Engineering University of PLA Nanjing210007China Research Institute of Structural Engineering and Disaster Reduction College of Civil EngineeringTongji UniversityShanghai200092China

The interface defeat phenomenon always occurs when a long-rod projectile impacting on the ceramic target with certain velocity,i.e.,the projectile is forced to flow radially on the surface of ceramic plates for a period of time without significant *** defeat has a direct effect upon the ballistic performance of the armor piercing projectile,which is studied numerically and theoretically at ***,by modeling the projectiles and ceramic targets with the SPH(Smoothed Particle Hydrodynamics)particles and Lagrange finite elements,the systematic numerical simulations on interface defeat are performed with the commercial finite element program *** different responses,i.e.,complete interface defeat,dwell and direct penetration,are reproduced in different types of ceramic targets(bare,buffered,radially confined and oblique).Furthermore,by adopting the validated numerical algorithms,constitutive models and the corresponding material parameters,the influences of projectile(material,diameter,nose shape),constitutive models of ceramic(JH-1 and JH-2 models),buffer and cover plate(thickness,constraints,material),as well as the prestress acted on the target(radial and hydrostatic) on the interface defeat(transition velocity and dwell time) are syste matically ***,based on the energy conservation approach and taking the strain rate effect of ceramic material into account,a modified model for predicting the upper limit of transition velocity is proposed and *** present work and derived conclusions can provide helpful reference for the design and optimization of both the long-rod projectile and ceramic armor.

关键词： Interface defeat Ceramic Transition velocity Numerical simulation Parametric study

Crack Initiation Mechanism of Z3CN20.09M Duplex Stainless Steel during Corrosion Fatigue in Water and Air at 290 °C

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Journal of Materials Science & Technology 2015年第11期31卷 1144-1150页

作者： H.C.wu B.yang y.Z.Shi q.Gao y.q.Wang State Key Laboratory for Advanced Metals and Materials University of Science and Technology Beijing Collaborative Innovation Center of Universal Iron & Steel Technology School of Materials Science and Engineering Anhui University of Technology

The crack initiation mechanism of a Z3CN20.09M duplex stainless steel （DSS） during corrosion fatigue （CF） in water and air at 290 ℃ was investigated by using a CF cracking machine and a scanning electron microscopy （SEM）. The cracks were initiated successively at the persistent stip bands （PSBs）, phase boundaries （PBs） and pitting corrosion points （PCPs） of the specimens when they were tested in water at 290 ℃, while in airat 290 ℃ the cracks were only initiated at the PSBs and PBs. And the cracks were found mainly to initiate at the PSBs and PBs when the specimens were tested in water and air at 290 ℃, respectively. The results also reveal that the cracks were likely to be initiated at the first 20% of fatigue life of the specimens tested in water at 290 ℃. However, the cracks were not found until 50% of fatigue life when tested in air at 290 ℃. Moreover, the crack numbers of the specimens tested in water at 290 ℃ were much more than those tested in air at 290 ℃.

关键词： Duplex stainless steel Corrosion fatigue Crack initiation High temperature water

Modified spherical cavity-expansion model for projectile penetration into concrete targets

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Acta Mechanica Sinica 2019年第3期35卷 518-534页

作者： y.Peng H.wu q.Fang X.Z.Kong College of Liberal Arts and Sciences National University of Defense TechnologyChangsha 410073China Key Laboratory of Performance Evolution and Control for Engineering Structures Tongji UniversityShanghai 200092China Research Institute of Structural Engineering and Disaster Reduction College of Civil EngineeringTongji UniversityShanghai 200092China State Key Laboratory for Disaster Prevention and Mitigation of Explosion and Impact PLA Amy Engineering UniversityNanjing 210007China

A modified spherical cavity-expansion model is developed in this paper.(1) We introduce a piecewise hyperbolic yield criterion suitable for pressure less than fc/3 to describe the mechanical behavior in the elastic region for the elastic-plastic response and modify the crack occurrence condition for the elastic-cracked-plastic response.(2) The hyperbolic yield criterion and a piecewise equation of state (EOS) are adopted for a better description of the plastic behavior of concrete material. Then, the modified model is validated by several projectile penetration tests in both the normal strength concrete (NSC) and ultra-high performance cement-based composite (UHPCC) targets. Finally, the hydrostatic pressure of the targets under rigid ogive-nosed projectile penetrations is found to be nearly within (0, 1.6 GPa), which usually exceeds the range that the shear strength-pressure test data covered. The influence of yield criterion on depth of penetration is discussed and it is recommended that the pressure should arrive at least 400 MPa in the related triaxial compression tests.

关键词： Dynamic cavity-expansion model Projectile Penetration Concrete Depth of penetration

Novel　Highly　Branched　Polyester　Nanoparticles(I)──Light-Scattering　Characterization

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Chemical Research in Chinese Universities 1998年第1期14卷 70-75页

作者： Ma, RJ wu, q Jilin Univ Inst Polymer Changchun 130023 Peoples R China Chinese Univ Hong Kong Dept Chem Shatin NT Peoples R China

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ＮｏｖｅｌＨｉｇｈｌｙＢｒａｎｃｈｅｄＰｏｌｙｅｓｔｅｒＮａｎｏｐａｒｔｉｃｌｅｓ（Ｉ）──Ｌｉｇｈｔ－ＳｃａｔｔｅｒｉｎｇＣｈａｒａｃｔｅｒｉｚａｔｉｏｎＭＡＲｏｎｇ－Ｊｉｕ（ＰｏｌｙｍｅｒＩｎｓｔｉｔｕｔｅ，ＪｉｌｉｎＵｎｉｖｅｒｓｉｔｙ，Ｃｈａ...

关键词： Branched Nanoparticles Novel Polyester Highly