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| 1 | Nonlinear hysteresis identification and compensation based on the discrete Preisach model of an aircraft morphing wing device manipulated by an SMA actuator显示文摘The conception of aircraft morphing wings thrives in aeronautics since the appearance of shape memory alloys(SMAs). An aircraft morphing wing device, manipulated by an SMA actuator, inherits the intrinsic nonlinear hysteresis from the SMA actuator, ending up with control disadvantages. Conventionally, systems with SMA actuators are constrained to bi-stable states to bypass the hysteresis region. Rather than retreating a morphing wing device to bi-stable states, this paper is dedicated to transcend the morphing wing device beyond the customary limit. A methodology of discrete Preisach modeling, which identifies the hysteresis of the morphing wing device, is proposed herein. An array of discrete equal-distance points is applied to the Preisach plane in order to derive the Preisach density over the partitioned unit of the Preisach plane. Discrete Preisach modeling is fulfilled by the discrete first-order reversible curve(DFORC). By utilizing the discrete Preisach model, the aircraft morphing wing device is simulated; the validity and accuracy of discrete Preisach modeling are demonstrated by contrasting the simulated outcome with experimental data of the major hysteretic loop and the wingspan-wise displacement over time; a comparison between simulation and experimental results exhibits consistency. Afterwards, a hysteresis compensation strategy put forward in this paper is implemented for quasi-linear control of the aircraft morphing wing device, which manifests a compensated shrinking hysteresis loop and attains the initiative of extending the morphing range to the intrinsic hysteretic region. | Yuchen CHEN Xing SHEN Jiefeng LI Jinjin CHEN | 2019 | Chinese Journal of Aeronautics2019，32，4： | 7 |
| 2 | A macroscopic multi-mechanism based constitutive model for the thermo-mechanical cyclic degeneration of shape memory effect of NiTi shape memory alloy显示文摘A macroscopic based multi-mechanism constitutive model is constructed in the framework of irreversible thermodynamics to describe the degeneration of shape memory effect occurring in the thermo-mechanical cyclic deformation of NiTi shape memory alloys(SMAs). Three phases,austenite A, twinned martensite Mtand detwinned martensite M^d, as well as the phase transitions occurring between each pair of phases( A → M^t, M^t→ A, A → M^d,M^d→ A, and M^t→ M^d) are considered in the proposed model. Meanwhile, two kinds of inelastic deformation mechanisms, martensite transformation-induced plasticity and reorientation-induced plasticity, are used to explain the degeneration of shape memory effects of NiTi SMAs. The evolution equations of internal variables are proposed by attributing the degeneration of shape memory effect to the interaction between the three phases(A, M^t, and M^d) and plastic deformation. Finally, the capability of the proposed model is verified by comparing the predictions with the experimental results of NiTi SMAs. It is shown that the degeneration of shape memory effect and its dependence on the loading level can be reasonably described by the proposed model. | Chao Yu Guozheng Kang Qianhua Kan | 2017 | Acta Mechanica Sinica2017，33，3： | 6 |
| 3 | Variable-model SMA-driven spherical robot显示文摘In this paper, we introduce a bionic spherical robot. This research has been inspired by the muscular organs and modularity of organisms such as starfish and octopuses. The robot that we fabricated uses five soft feet to crawl like a starfish, and the robotic feet are driven by the shape memory alloy springs. The robotic spherical structure and the soft feet were fabricated by 3 D printing. The robotic feet were made of silicone gel;these feet could bend upward and downward to help the robot to crawl on the ground and roll down a slope. The shell separation module installed inside the robot could divide the robot into two identical modules, and this smart structure could enhance the robotic flexibility in a small space. We performed force analysis and robotic simulation, and the results verified the feasibility of the model. The robot can switch between rigidity and softness by using human control. Three types of gaits have been proposed for controlling robotic movement and improving robotic flexibility in movement;these include rolling, crawling, and avoiding obstacles. The results of this study indicate that the variable-model design of the robot is an effective way to enhance the flexibility of soft robots. | PAN Jie SHI ZhenYun WANG TianMiao | 2019 | Science China(Technological Sciences)2019，62，8： | 5 |
| 4 | Analysis of the mass of behind-armor debris generated by RHA subjected to normal penetration of variable cross-section EFP显示文摘Analyzing the mass of behind-armor debris (BAD) generated by Rolled Homogeneous Armor (RHA) subjected to normal penetration of variable cross-section Explosively Formed Projectile (EFP) is the purpose of this paper. So theoretical analysis, numerical simulation and experimental data are combined to analyze the influence of variable cross-section characteristic on the time history of crater radius. Moreover the relationships between time history of crater radius (as well as mass of BAD) and the thickness of RHA (from 30mm to 70 mm) and the impact velocity of EFP (1650 m/s to 1860 m/s) are also investigated. The results indicate that: 1) being compared to the variable cross-section characteristic is ignored, the theoretical time history of crater radius is in better agreement with the simulation results when the variable cross-section characteristic is considered;2) being compared to the other three conditions of plug, the theoretical mass of BAD is in the best agreement with the simulation results when the shape of plug is frustum of a cone and the angle between generatrix and bottom is 45- and the axial length of mushroom is considered. | Boyang Xing Dongjiang Zhang Zhenyan Guo Yunhui Hou Rui Guo Rongzhong Liu Liang Chen Hao Zhou Yongliang Yang Jianhua Luo | 2019 | Defence Technology(防务技术)2019，15，3： | 4 |
| 5 | Numerical investigation of edge configurations on piston-modal resonance in a moonpool induced by heaving excitations显示文摘The renormalization group (RNG) turbulent model is used to investigate the fluid resonance in a moonpool formed by two identical rectangular hulls under synchronous heaving excitation (e.g., a catamaran or dual pontoon). The numerical model is validated against the available experimental data, and accurate numerical solutions are obtained. The present study focuses on the amplitude of the moving hulls and the edge configuration of the moonpool entrance, as well as their influences on the piston-modal resonant wave in the moonpool. The dependence of the resonant wave amplitude in the moonpool on the heaving amplitude, the characteristic moonpool dimensions and the local velocity magnitude is derived based on a theoretical analysis, and the results are in good agreement with the RNG turbulent solutions. Five different edge profiles are considered, including two convex edges, two concave edges (both with various dimensions), and a sharp edge. Numerical examinations show that the edge configuration has a significant influence on the piston-modal resonant responses, a larger opening size leading to a higher resonant frequency and a larger resonant wave amplitude in the moonpool. Various flow patterns of the piston-modal resonance in the vicinity of the moonpool entrance are also identified, mainly depending on the edge profile. More intensive turbulent and vortical flows give rise to more significant dissipation, accounting for the smaller relative wave amplitude in the moonpool. With the increase of the heaving amplitude, the relative piston-modal resonant amplitude is decreased in an approximate power function. Within the scope of this work, the numerical investigations show that the piston-modal resonant frequency is hardly affected by the heaving amplitude. | Sheng-chao Jiang Pei-wen Cong Lei Sun Chang-feng Liu | 2019 | Journal of Hydrodynamics2019，31，4： | 3 |
| 6 | DEFICIENT INFORMATION MODELING OF MECHANICAL PRODUCTS FOR CONCEPTUAL SHAPE DESIGN显示文摘In allusion to the deficient feature of product information in conceptual design, a framework of deficient information modeling for conceptual shape design is put forward, which includes qualitative shape modeling (a qualitative solid model), uncertain shape modeling (an uncertain relation model) and imprecise shape modeling (an imprecise region model). In the framework, the qualitative solid model is the core, which represents qualitatively (using symbols) the conceptual shapes of mechanical products. The uncertain relation model regarding domain relations as objects and the imprecise region model regarding domains as objects are used to deal with the uncertain and imprecise issues respectively, which arise from qualitative shape modeling or exist in product information itself. | Liu Jihong Shu Huilin CAD Center,Huazhong University of Science and Technology,Wuhan 430074,China | 2002 | Chinese Journal of Mechanical Engineering2002，15，1： | 3 |
| 7 | Estimating leaf area index by inversion of reflectance model for semiarid natural grasslands显示文摘The study developed an integrated reflectance model combining radiative transfer and geometric optical properties in order to inverse leaf area index(LAI) of semiarid natural grasslands.In order to better link remote sensing information with land plants,and facilitate regional and global climate change studies,the model introduced a simple but important geometrical similarity parameter related to plant crown shapes.The model revealed the influences of different plant crown shapes(such as spherical,cylindrical/cuboidal and conic crowns) on leaf/branch angle distribution frequencies,shadow ground coverage,shadowed or sunlit background fractions,canopy reflectance,and scene reflectance.The modeled reflectance data agreed with the measured ones in the three Leymus chinensis steppes with different degradation degrees,which validated the reflectance model.The lower the degradation degree was,the better the modeled data agreed with the measured data.After this reflectance model was coupled with the optimization inversion method,LAI over the entire study region was estimated once every eight days using the eight-day products of surface reflectance obtained by multi-spectral Moderate-Resolution Imaging Spectroradiometer(MODIS) during the growing seasons in 2002.The temporal and spatial patterns of inversed LAI for the steppes with different cover degrees,swamps,flood plains,and croplands agreed with the general laws and measurements very well.But for unused land cover types(sands,saline,and barren lands) and forestlands,totally accounting for about 10% of the study region,the reasonable LAI values were not derived by inversing,requiring further revising of the model or the development of a new model for them. | ZHANG Na ZHAO YingShi | 2009 | Science China Earth Sciences2009，52，1： | 3 |
| 8 | Experimental Study of Air Layer Drag Reduction with Bottom Cavity for A Bulk Carrier Ship Model显示文摘Air lubrication by means of a bottom cavity is a promising method for ship drag reduction. The characteristics of the bottom cavity are sensitive to the flow field around the ship hull and the effect of drag reduction, especially the depth of the bottom cavity. In this study, a ship model experiment of a bulk carrier is conducted in a towing tank using the method of air layer drag reduction (ALDR) with different bottom cavity depths. The shape of the air layer is observed, and the changes in resistance are measured. The model experiments produce results of approximately 20% for the total drag reduction at the ship design speed for a 25-mm cavity continuously supplied with air at Cq = 0.224 in calm water, and the air layer covers the whole cavity when the air flow rate is suitable. In a regular head wave, the air layer is easily broken and reduces the drag reduction rate in short waves, particularly when λ/Lw1 is close to one;however, it still has a good drag reduction effect in the long waves. | WU Hao OU Yong-peng | 2019 | China Ocean Engineering2019，33，5： | 3 |
| 9 | Spatial characteristics and driving forces of the morphological evolution of East Lake,Wuhan显示文摘The shapes of the urban lakes in Wuhan city have been strongly influenced by the rapid industrialization and urbanization experienced in recent decades.Based on topographic maps and remote sensing images,the temporal and spatial changes of East Lake,Wuhan city,over the past two decades were analyzed.The landscape shape index(LSI)and centroid method were applied to analyze the evolution of lake morphology and its causes.Several key results were obtained.(1)The surface area of East Lake decreased sharply by 2.13 km2 from 1995 to 2005,and slightly by 1.00 km2 from 2005 to 2015.The shoreline length of East Lake displayed a continuous trend of decline during the study period:The length reduced by 21.89 km from 1995 to 2005,and by 0.67 km from 2005 to 2015.The LSI values,7.04(1995),6.46(2005),and 6.28(2015),displayed an accelerated downward trend,indicating a reduction of complexity in East Lake and the intensification of manual interventions in the water body.(2)The changes to East Lake displayed a clear temporal and spatial heterogeneity.The centroid of East Lake moved northeast from 1995 to 2005 and southeast from 2005 to 2015.(3)The reduction in the area of East Lake was mainly affected by human activities.A lake area of about 4.8 km2 was converted to other land uses during 1995-2005,most of which was unused land,whereas from 2005 to 2015,0.43 km2 of the lake area was converted into built-up land,and 0.25 km2 was converted into other land uses.The reduction in area was caused by infrastructure construction by the government,the development of the real estate industry,illegal construction by villagers,and the development of scenic spots for tourism.The driving forces of this reduction included Wuhan's growing population,and the rapid development of the economy and urbanization between 1995 and 2015,which has resulted in a large demand for land.Finally,a formation mechanism model was constructed by analyzing the causes of East Lake's morphological evolution. | 陈昆仑 刘小琼 陈溪 郭宇琪 董寅 | 2020 | Journal of Geographical Sciences2020，30，4： | 2 |
| 10 | Shape phase transitions in nuclei:Effective order parameters and trajectories显示文摘We analyze systematically the effective order parameters in nuclear shape phase transition both in experiments and in the interacting boson model. We find that energy ratios and B(E2) ratios can distinguish the first from the second-order phase transition in theory above a certain boson number N (about 50), but in experiments, only those quantities, such as E(L1+)/E(02+) and B(E2; (L+2)1 → L1)/B(E2; 21 → 01), etc., of which the monotonous transitional behavior in the second-order phase transition is broken in the first order phase transition independent of N, are qualified as the effective order parameters. By implementing the originally proposed effective order parameters and the new ones, we find that the isotones with neutron number Nn = 62 are a trajectory of the second order phase transition. In addition, we predict that the transitional behavior of isomer shifts of Xe, Ba isotopes and Nn = 62 isotones is approximately monotonous due to the finiteness of nuclear system. | ZHANG Yu1,2, HOU ZhanFeng2 & LIU YuXin2,3 1Department of Physics, Liaoning Normal University, Dalian 116029, China 2Department of Physics and the State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing 100871, China 3Center of Theoretical Nuclear Physics, National Laboratory of Heavy Ion Accelerator, Lanzhou 720000, China | 2011 | Science China(Physics,Mechanics & Astronomy)2011，54，S1： | 2 |
| 11 | Modeling size-dependent thermo-mechanical behaviors of shape memory polymer Bernoulli-Euler microbeam显示文摘The objective of this paper is to model the size-dependent thermo-mechanical behaviors of a shape memory polymer (SMP) microbeam.Size-dependent constitutive equations,which can capture the size effect of the SMP,are proposed based on the modified couple stress theory (MCST).The deformation energy expression of the SMP microbeam is obtained by employing the proposed size-dependent constitutive equation and Bernoulli-Euler beam theory.An SMP microbeam model,which includes the formulations of deflection,strain,curvature,stress and couple stress,is developed by using the principle of minimum potential energy and the separation of variables together.The sizedependent thermo-mechanical and shape memory behaviors of the SMP microbeam and the influence of the Poisson ratio are numerically investigated according to the developed SMP microbeam model.Results show that the size effects of the SMP microbeam are significant when the dimensionless height is small enough.However,they are too slight to be necessarily considered when the dimensionless height is large enough.The bending flexibility and stress level of the SMP microbeam rise with the increasing dimensionless height,while the couple stress level declines with the increasing dimensionless height.The larger the dimensionless height is,the more obvious the viscous property and shape memory effect of the SMP microbeam are.The Poisson ratio has obvious influence on the size-dependent behaviors of the SMP microbeam.The paper provides a theoretical basis and a quantitatively analyzing tool for the design and analysis of SMP micro-structures in the field of biological medicine,microelectronic devices and micro-electro-mechanical system (MEMS) self-assembling. | Bo ZHOU Xueyao ZHENG Zetian KANG Shifeng XUE | 2019 | Applied Mathematics and Mechanics(English Edition)2019，40，11： | 2 |
| 12 | Particle number scale invariant feature of the states around the critical point of the first order nuclear shape phase transition显示文摘We study systematically the evolutive behaviors of some energy ratios,E2 transition rate ratios and isomer shift in the nuclear shape phase transitions.We find that the quantities sensitive to the phase transition and independent of free parameter(s) are approximately particle number N scale invariant around the critical point of the first order phase transition,similar to that in the second order phase transition. | ZHANG Yu HOU ZhanFeng LIU YuXin | 2009 | Science China(Physics,Mechanics & Astronomy)2009，52，10： | 1 |
| 13 | Three-dimensional constitutive model for magneto-mechanical deformation of NiMnGa ferromagnetic shape memory alloy single crystals显示文摘Existing experimental results have shown that four types of physical mechanisms, namely, martensite transformation, martensite reorientation, magnetic domain wall motion and magnetization vector rotation, can be activated during the magneto-mechanical deformation of NiMnGa ferromagnetic shape memory alloy (FSMA) single crystals. In this work, based on irreversible thermodynamics, a three-dimensional (3D) single crystal constitutive model is constructed by considering the aforementioned four mechanisms simultaneously. Three types of internal variables, i.e., the volume fraction of each martensite variant, the volume fraction of magnetic domain in each variant and the deviation angle between the magnetization vector, and easy axis are introduced to characterize the magneto-mechanical state of the single crystals. The thermodynamic driving force of each mechanism and the thermodynamic constraints on the constitutive model are obtained from Clausius's dissipative inequality and constructed Gibbs free energy. Then, thermodynamically consistent kinetic equations for the four mechanisms are proposed, respectively. Finally, the ability of the proposed model to describe the magneto-mechanical deformation of NiMnGa FSMA single crystals is verified by comparing the predictions with corresponding experimental results. It is shown that the proposed model can quantitatively capture the main experimental phenomena. Further, the proposed model is used to predict the deformations of the single crystals under the non-proportional mechanical loading conditions. | Chao Yu Guozheng Kang Di Song Xi Xie | 2019 | Acta Mechanica Sinica2019，35，3： | 1 |
| 14 | Controllable Bending of Bi-hydrogel Strips with Differ ent ial Swelling显示文摘Bi-hydrogel strips consisting of a highly swelling layer and a non-swelling layer are investigated in this study,in which the differential swelling capabilities and mismatch strain in the composite structure drive the strips into a bending configuration when being exposed to solvents.A modified analytical model originated from Timoshenko theory on bi-material beam is proposed to predict the swelling-induced bending shape of the bi-hydrogel strips,with explicit relations of bending curvature and mid-span deflection versus mismatch strain.Different sets of experiments were performed to verify the analytical model and its solutions,in which the swellinginduced mismatch strain was systematically tuned by the selection of saline concentration.The broad agreements bet ween the t heore tical and experimen tai results indicate that the modified analytical model can be used to guide the design of morphing elements by modulating layer-bylayer mismatches in gel composites to produce precise and complex shape transformations for practical applications. | Yi Wu Xingpeng Hao Rui Xiao Ji Lin Zi Liang Wu Jun Yin Jin Qian | 2019 | Acta Mechanica Solida Sinica2019，32，5： | 0 |
| 15 | Definition and Verification of Shape Meter Method显示文摘Two experimental methods were adopted to verify the correctness and practicability of the shape meter method: one is to roll aluminum plate, calculate the shape stiffness of mill and rolled piece, and then measure aluminum plate crown to verify shape stiffness equation; the other is to calculate the measured off-line data of hot continuous roll and verify the shape mathematical model for measuring and controlling by self-adaptation method. | ZHANG Jin-zhi DUAN Chun-hua ZHU Jian-qin | 2002 | Journal of Iron and Steel Research(International)2002，9，2： | 0 |
| 16 | Using Gaussian Mixture Model to Fix Errors in SFS Approach Based on Propagation显示文摘A new Gaussian mixture model is used to improve the quality of propagation method for SFS in this paper. The improved algorithm can overcome most difficulties of propagation SFS method including slow convergence, interdependence of propagation nodes and error accumulation. To slow convergence and interdependence of propagation nodes, stable propagation source and integration path are used to make sure that the reconstruction work of each pixel in the image is independent. A Gaussian mixture model based on prior conditions is proposed to fix the error of integration. Good result has been achieved in the experiment for Lambert composite image of the front illumination. | Wenmin Huang Jiquan Ma Enbin Zhang | 2016 | 国际计算机前沿大会会议论文集2016，，1： | 0 |
| 17 | Constitutive model for shape memory alloy torsion actuator显示文摘Shape memory alloy ( SMA) torsion actuator is one of the key approaches realizing adaptive wings in airplanes. In this paper,the actuator is made up of SMA wires and a thin-walled tube,in which the SMA wires are twisted and affixed around the surface of the tube at an angle referenced to the center axis of the tube. A thermo-mechanical constitutive model is developed to predict the thermo-mechanical behaviors of the SMA torsion actuator based on the knowledge of solid mechanics. The relationship between the torsion-angle and tem- perature is numerically calculated by using the thermo-mechanical constitutive model coupled with the SMA phase transformation model developed by Zhou and Yoon. The numerical results are compared with the relative experimental results finished by Xiong and Shen. Influences of the twist-angle of SMA wires and geometrical factors on the primary actuation performances of the SMA torsion actuator are also numerically investigated based on the thermo-mechanical constitutive model coupled with the SMA phase transformation model developed by Zhou and Yoon. Results show that the thermo-mechanical constitutive model can well predict the thermo-mechanical behaviors of the SMA torsion actuator. | 周博 冷劲松 邹广平 刘彦菊 周利民 | 2010 | Journal of Harbin Institute of Technology(New Series)2010，17，2： | 0 |
| 18 | Microwave Application Shape Anisotropy of Micro-sized Bamboo Blind Shape显示文摘Electromagnetic anisotropic characteristics in micro-sized water bamboo blind shape are observed by high frequency electromagnetic computation,which is applied to the material constants estimation.In assuming that the micro-sized unit structure is repeated in 3-dimensional space and its size is much smaller than the electromagnetic wave length,the micro-sized electromagnetic field calculation is carried out.If the micro-structure shapes of the material are different even if they are the same volume rate,different dielectric constant characteristics are provided.The reasons are considered to be a generation of de-electrification within the dielectric material. | Keisuke Fujisaki | 2012 | Journal of Iron and Steel Research(International)2012，19，S2： | 0 |
| 19 | DECOUPLED MODEL FOR FLATNESS CONTROL IN 4-H CVC COLD ROLLING MILLS显示文摘INTRODUCTIONTheprecisecontrolofrolgapin4hCVCmilsisparticularlydificultduetothecomplexinteractionsbetwenworkrolshiftingandben... | Zhong Jue and Chen Jie College of Mechanical and Electrical Engineering, Central South University of Technology, Changsha 410083, P. R. China | 1998 | 中国有色金属学会会刊:英文版1998，8，4： | 0 |
| 20 | Active Shape Models Using Scale Invariant Feature Transform显示文摘A new active shape models (ASMs) was presented, which is driven by scale invariant feature transform (SIFT) local descriptor instead of normalizing first order derivative profiles in the original formulation, to segment lung fields from chest radiographs. The modified SIFT local descriptor, more distinctive than the general intensity and gradient features, is used to characterize the image features in the vicinity of each pixel at each resolution level during the segmentation optimization procedure. Experimental results show that the proposed method is more robust and accurate than the original ASMs in terms of an average overlap percentage and average contour distance in segmenting the lung fields from an available public database. | 史勇红 戚飞虎 栾红霞 吴国荣 | 2007 | Journal of Shanghai Jiaotong university(Science)2007，12，6： | 0 |
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