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Journal of Rock mechanics and Geotechnical Engineering 2024年第7期16卷 2732-2748页

作者： Javad Ghorbani Arooran Sounthararajah Troyee Tanu Dutta Jayantha Kodikara ARC Smart Pavements Hub Dept.of Civil EngineeringMonash UniversityVIC3800Australia

This study introduces an advanced finite element model for the light weight deflectometer(LWD),which integrates contact mechanics with fully coupled *** simulating LWD tests on granular soils at various saturation levels,the model accurately reflects the dependence of the LWD modulus on dry density,water content,and effective *** model addresses and overcomes the limitations of previous finite element models for this specific ***,this research presents the first experimentally validated fully coupled contact impact ***,the research provides a comparative assessment of elastoplastic and nonlinear elastic models and contrasts an enriched node-tosegment method(developed in this study)with the more precise mortar technique for contact *** comparisons reveal unique advantages and challenges for each ***,the study underscores the importance of careful application of the LWD modulus,emphasising the need for sophisticated tools to interpret soil behaviour accurately.

关键词： Granular soils Plasticity Finite element analysis Contact mechanics Modulus Degree of saturation

EXPERIMENTAL INVESTIGATION INTO PLASTIC DAMAGE OF MICROVOIDS WITH INTERACTION

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Acta Mechanica Sinica 1997年第3期13卷 280-288页

作者：方竞倪受庸杨宏伟白树林戴福隆 dept.of mechanics & Engng.Science Peking UniversityBeijing 100871China dept.of Engng.mechanics Tsinghua UniversityBeijing 100084China

A mechanism of plastic how localization in ductile matter near microvoids is studied. The voids with the size-scale of micromillimeter exist in sheet specimens under tensile loading, and the plastic strain held around voids is obtained by digital image processing of deformed grids. The size growth of the microvoids, the spacing change of the neighboring voids, and the development of shear bands in the ligament between the voids, are presented by experimental results accompanied with the plastic strain distribution, that gives good interpretation to the process of void growth and coalescence with the how localization in the ligaments.

关键词： void damage flow localization plastic strain field void interaction

STUDY OF THERMAL DEFORMATION OF MICROELECTRONICS PACKAGING PRODUCT BY INTERFEROMETRIC TECHNIQUE

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Acta Mechanica Sinica 1997年第2期13卷 186-192页

作者：卿新林王国韬戴福隆 dept.of Engineering mechanics Tsinghua UniversityBeijing 100084China

In this paper, the out-of-plane deformation of silicon surface of Direct Chip Attachment (DCA) assembly, under thermal loading, was measured in real-time by Twyman/Green interferometry. The contour maps of the out-of-plane displacement fields of silicon surface under thermal loading and cycling of various temperature were obtained, Experimental results show that the relation between the out-of-plane displacement and temperature is nonlinear and varies with temperature cycling, due to nonlinear mechanical behavior of the materials used in electronic packaging. A comparison of the aut-of-plane displacement Gelds of silicon surface measured by T/G interferometry in real-time and replicating technique of high temperature specimen grating of moire interferometry was made.

关键词： electronic packaging thermal deformation Twyman/Green interferometry Moire interferometry

STUDY OF CONSTITUTIVE RELATIONS FOR PSEUDO-ELASTICITY AND SHAPE MEMORY BEHAVIOR

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Acta Mechanica Sinica 1993年第1期9卷 44-52页

作者：王志刚黄克智 dept.of Engineering mechanics Tsinghua UniversityBeijing China 100084

Constitutive relations are given for the description of the deformation behavior of shape memory materials. The deformation is the superposition of the elastic, the thermal and the phase transformation deformation caused by the transformation from one to the other among the high temperature phase, the low temperature phase and the stress induced phase. The phase transformation is controlled by the driving force, i.e., the Gibbs energy difference between the phases.

关键词： shape memory material pseudo-elastic deformation, shape memory deformation phase transformation constitutive relations

CONSTRUCTION OF RECTANGULAR DISPLACEMENT-BASED ELEMENT FOR THICK/THIN PLATES

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Acta Mechanica Sinica 1993年第2期9卷 163-170页

作者：卜小明龙驭球 dept.of mechanics Tianjin UniversityTianjin 300072China dept.of Civil Engineering Tsinghua UniversitvBeijing 100084China

In this paper,a method of constructing displacement-based elment for thick/thin plates is devel- oped by using the technique of generalized compatibility,and a rectangular displacement-based element with 12 degrees of freedom for thick/thin plates is *** method enjoys a good accuracy with simple formulation and is free of shear- locking as the thickness of the plate approaches zero.

关键词： thick plate thin plate generalized compatibility finite element

EVALUATION OF THE PROBABILITY DISTRIBUTION OF PITTING CORROSION FATIGUE LIFE IN AIRCRAFT MATERIALS

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Acta Mechanica Sinica 2003年第3期19卷 247-252页

作者：王清远 N.KAWAGOISHI Q.Chen R.M.PIDAPARTI dept.of Civil Eng.and mechanics Sichuan UniversityChengdu 610065China

Corrosion and fatigue properties of aircraft materials are known to have a considerable scatter due to the random nature of materials,loading,and environmental conditions.A probabilistic approach for predicting the pitting corrosion fatigue life has been investigated which captures the effect of the interaction of the cyclic load and corrosive environment and all stages of the corrosion fatigue process (*** pit nucleation and growth,pit-crack transition,short- and long-crack propagation).The probabilistic model investigated considers the uncertainties in the initial pit size,corrosion pitting current,and material properties due to the scatter found in the experimental *** Carlo simulations were performed to define the failure probability *** cumulative distribution functions of fatigue life agreed reasonably well with the existing experimental data.

关键词： pitting corrosion fatigue probabilistic modeling fatigue life prediction life evaluation aeronautic material corrosive environment Probabilistic Model Cyclic loads Fatigue life corrosion fatigue life Cumulative Probability Distribution pits Experimental data CORROSION FATIGUE Probability distribution Corrosion

A UNIFIED ENERGY APPROACH TO A CLASS OF MICROmechanics MODELS FOR COMPOSITE MATERIALS

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Acta Mechanica Sinica 1995年第1期11卷 59-75页

作者：黄永刚黄克智胡凯雄 A.Chandra dept.of Aerospace and Mech.Eng. The University of ArizonaTucsonAZ 85721USA dept.of Engineering mechanics Tsinghua UniversityBeijing 100084China

Several micromechanics models for the determination of composite moduli are investigated in this paper,including the dilute solution,self-consistent method,generalized self-consistent method,and Mori-Tanaka's *** mi- cromechanical models have been developed by following quite different approaches and physical *** is shown that all the micromechanics models share a common ground,the generalized Budiansky's energy-equivalence *** dif- ference among the various models is shown to be the way in which the average strain of the inclusion phase is *** a bonus of this theoretical development,the asymmetry suffered in Mori-Tanaka's method can be circumvented and the applica- bility of the generalized self-consistent method can be extended to materials contain- ing microcracks,multiphase inclusions,non-spherical inclusions,or non-cylindrical *** relevance to the differential method,double-inclusion model,and Hashin-Shtrikman bounds is also *** application of these micromechanics models to particulate-reinforced composites and microcracked solids is reviewed and some new results are presented.

关键词： micromechanics models energy-equivalence framework dilute solution self-consistent method generalized self-consistent method Mori-Tanaka's method

Application of a k-ε Model to Heat Transfer in Impinging Flows

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Journal of Thermal Science 2004年第1期13卷 62-66页

作者： Bart Merci Chris De Langhe Koen Lodefier Erik Dick Ghent University Dept.of FlowHeat and Combustion MechanicsSint-Pietersnieuwstraat 41B-9000 GentBelgiumGhent UniversityDept.of FlowHeat and Combustion MechanicsSint-Pietersnieuwstraat 41B-9000 GentBelgiumGhent UniversityDept.of FlowHeat and Combustion MechanicsSint-Pietersnieuwstraat 41B-9000 GentBelgiumGhent UniversityDept.of FlowHeat and Combustion MechanicsSint-Pietersnieuwstraat 41B-9000 GentBelgium

Local heat transfer is predicted in turbulent axisymmetric jets, impinging onto a flat plate. A non-linear k-e model is used, in which both the constitutive law for the turbulent stresses and the transport equation for the turbulent dissipation rate e have an important contribution in the improved heat transfer predictions. The shape of the Nusselt number profiles, expressing dimensionless heat transfer, as well as the stagnation point value, are well predicted for different distances between the nozzle exit and the plate. Accurate flow field predictions are the basis for good heat transfer predictions. For a fixed Reynolds number, the influence of the nozzle-plate distance is well captured. For a fixed distance, the influence of the Reynolds number is correctly reproduced. Comparisons are made to a low-Reynolds standard k-e model and the v2-f model. A thorough discussion is found in [4]. Only a summary of those results is discussed here, while some new results are also presented.

关键词： local heat transfer impinging jets non-linear k-ε model.

Continuous-wave operation of 1550 nm low-threshold triple-lattice photonic-crystal surface-emitting lasers

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Light(Science & Applications) 2024年第3期13卷 446-453页

作者： Ziye Wang Xia Liu Pinyao Wang Huanyu Lu Bo Meng Wei Zhang Lijie Wang Yanjing Wang Cunzhu Tong State Key Laboratory of Luminescence and Applications Changchun Institute of OpticsFine Mechanics and PhysicsChinese Academy of SciencesChangchun 130033China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijing 100049China Central Research Institute Planning dept 2012 LabsHuawei Technologies Company Ltd.Shenzhen 518129China

Benefitting from narrow beam divergence,photonic crystal surface-emitting lasers are expected to play an essential role in the ever-growing fields of optical communication and light detection and *** operating with 1.55μm wavelengths have attracted particular attention due to their minimum fiber loss and high eye-safe ***,high interband absorption significantly decreases their performance at this 1.55μm ***,stronger optical feedback is needed to reduce their threshold and thus improve the output *** this goal,photonic-crystal resonators with deep holes and high dielectric contrast are often ***,the relevant techniques for high-contrast photonic crystals inevitably complicate fabrication and reduce the final *** this paper,we demonstrate the first continuous-wave operation of 1.55μm photonic-crystal surface-emitting lasers by using a‘triple-lattice photonic-crystal resonator’,which superimposes three lattice point groups to increase the strength of in-plane optical *** this geometry,the in-plane 180°coupling can be enhanced threefold compared to the normal single-lattice *** theoretical and experimental investigations demonstrate the much lower threshold current density of this structure compared to‘single-lattice’and‘double-lattice’photonic-crystal resonators,verifying our design *** findings provide a new strategy for photonic crystal laser miniaturization,which is crucial for realizing their use in future high-speed applications.

关键词： resonator crystal lattice

INERTIA EFFECTS OF THE FLUID AND CYLINDER IN COAXIAL CYLINDRICAL RHEOMETER

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Acta Mechanica Sinica 1998年第3期14卷 234-238页

作者：张建保匡震邦 dept.of Physics The Forth Military Medical UniversityXi'an 710032China dept.of Eng.mechanics Shanghai Jiaotong UniversityShanghai 200240China

The inertias of the fluid and the inner cylinder in coaxial cylinder rheometer (CACR) have great influence on the unsteady flow of non-Newtonian fluid. Even for the Newtonian fluid there exist the so called stress overshoot phenomenon. This phenomenon was studied and a method correcting the measured results for an unsteady flow in the rheometer was proposed. It is found that the inertia effect of the fluid can be ignored when the gap between cylinders is small. (Edited author abstract) 11 Refs.

关键词： inertia rheometer fluid hemorheology