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| 1 | Particle dynamics in dense shear granular flow显示文摘粒子动力学在一环形砍小粒的流动用包装部分的分离元素方法,和影响被学习,砍率和磨擦系数被分析。我们证明批评收拾行李部分的存在在 shear 存在小粒的流动。当收拾行李的部分比这批评价值低时,吝啬的正切的速度侧面展出一个率无关的特征。然而,当收拾行李的部分超过这批评价值时,正切的速度侧面成为率依赖者并且逐渐地变化从对线性与增加非线性砍率。而且,我们从 unjammed 国家发现连续转变到堵塞国家在一 shear 收拾行李的部分增加的小粒的流动。在这转变进程,力量分发清楚地变化,接触力量网络也展出不同特征。关键词砍小粒的流动 - 正切的速度侧面 - 批评收拾行李部分 - 力量分发 - 堵塞状态工程被国家天赋的关键工程支持中国(10532040 ) 和大学(IRT 0628 ) 里的 Changjiang 学者和创新研究队的计划的科学基础。 | Dengming Wang Youhe Zhou | 2010 | Acta Mechanica Sinica2010，26，1： | 8 |
| 2 | Statistics of contact force network in dense granular matter显示文摘We investigate the distribution of contact forces in a static granular system and in annular shear granular flow, using the discrete element method, and considering the influences of both packing fraction and friction coefficient. We find the existence of a critical packing fraction. If the packing fraction is lower than this critical value, all contact forces in granular system vanish. For shear granular flow, the critical packing fraction is significantly smaller than that for static granular system. The distribution of the contact forces also exhibits different forms, especially at lower packing fraction. We also investigate the spatial configuration of contact network using the angular distribution of contact forces. In static granular systems, the contact force network is approximately isotropic, while in shear granular flow, it exhibits a distinct anisotropy along the shear direction. | DengmingWang Youhe Zhou | 2010 | Particuology2010，8，2： | 6 |
| 3 | Discrete element simulation of localized deformation in stochastic distributed granular materials显示文摘The deformation in granular material under loading conditions is a problem of great interest currently. In this paper,the micro-mechanism of the localized deformations in stochastically distributed granular materials is investigated based on the modi-fied distinct element method under the plane strain conditions,and the influences of the confining pressure,the initial void ratio and the friction coefficient on the localized deformation and the stability of granular materials are also studied. It is concluded,based on the numerical simulation testing,that two crossed shear sliding planes may occur inside the granular assembly,and deformation patterns vary with the increasing of transverse strain. These conclusions are in good agreement with the present experimental results. By tangential velocity profiles along the direction normal to the two shear sliding planes,it can be found that there are two different shear deformation patterns: one is the fluid-like shear mode and the other is the solid-like shear mode. At last,the influences of various material parameters or factors on localized deformation features and patterns of granular materials are discussed in detail. | WANG DengMing ZHOU YouHe | 2008 | Science China(Physics,Mechanics & Astronomy)2008，51，9： | 6 |
| 4 | PERTURBATION ANALYSIS FOR MAGNETO-PLASTIC INSTABILITY OF FERROMAGNETIC BEAM-PLATES WITH GEOMETRIC IMPERFECTION显示文摘The magneto-plastic instability of a ferromagnetic beam-type plate with simple supports and small initial imperfection is analytically investigated in this paper for that the plastic deformation of the plate with a linear-strain hardening relation is considered when the plate is located in a strong uniformly distributed magnetic ?eld. After the distribution of magnetic ?elds related to the de?ected con?guration of plate is imaginably divided into two parts, i.e., one is related to the ?at plate and the other dependent on the perturbation of magnetic ?elds for which the plate con?guration changes from the ?at into the deformed state, the perturbation technique is employed to analyze the distribution of the perturbation magnetic ?elds in and out-of the magnetic medium of the ferromagnetic structure in a transverse magnetic ?eld, which leads to some analytical formulae/solutions for the magnetic ?elds and the resulting magnetic force exerted on the plate. Based on them, the magneto-plastic buckling and snapping of the plate in a transverse magnetic ?eld is discussed, and the critical magnetic ?eld is analytically formulated in terms of the parameters of geometry and material of the plate employed by solving the governing equation of the magneto-plastic plate in the applied magnetic ?eld. Further, the sensitivity of the initial imperfection on the magneto-plastic instability, expressed by an ampli?cation function, is obtained by solving the dynamic equation of de?ection of the plate after the inertial force in the transverse direction is taken into account. The results obtained show that the critical magnetic ?eld is sensitive to the plastic characteristic, e.g., hardening coe?cient, and the instability mode and de?ection of the plate are dependent on the geometrical imperfection as well. | Zhou Youhe Gao Yuanwen Zheng Xiaojing | 2004 | Acta Mechanica Solida Sinica2004，17，4： | 6 |
| 5 | SINGULAR BEHAVIORS OF INTERFACIAL CRACKS IN 2D MAGNETOELECTROELASTIC BIMATERIALS显示文摘The singular characteristics of stress,electric displacement and magnetic induction fields near the tip of impermeable interfacial cracks in two-dimensional magnetoelectroelastic bimaterials are studied using the generalized Stroh formalism.Two types of singularities are ob-tained:one is the oscillating singularity 1/2±iε,the other is the non-oscillating singularity 1/2±κ.It is found that the non-zero parameters ε and κ cannot coexist for one transversely isotropic MEE bimaterial,a similar result is obtained for transversely isotropic piezoelectric bimaterials. | Cuiying Fan Youhe Zhou Han Wang Minghao Zhao | 2009 | Acta Mechanica Solida Sinica2009，22，3： | 5 |
| 6 | Numerical analysis of magnetization AC losses in high-temperature superconducting slabs subjected to uniform strains显示文摘High-temperature superconductors in superconductor apparatuses are subjected to mechanical strains under operating conditions.These strains cause the degradation of the critical current densities and influence AC losses in the superconductors.Based on the dynamic process of thermomagnetic interaction,we report the results of numerical analysis of AC losses in an infinite high-temperature superconducting slab subjected to a uniform in-plane strain in an alternating external magnetic field parallel to the sample surface.The numerical analysis shows the details of electromagnetic phenomena in the slab and the dependences of AC loss on various external parameters including the uniform strain in the slab and the amplitude and frequency of the external magnetic field.In this paper,we find that whether the magnetic field fully penetrates the superconductor is the key factor that influences the features of AC loss.When the magnetic field cannot fully penetrate the superconductor,the loss rises with increasing strain or decreasing frequency.When the magnetic field can fully penetrate the superconductor,the feature is just opposite.We also analyze the effects of periodic strain on AC loss.It is interesting to find that when the periodic strain frequency equals the external magnetic field frequency,the AC loss reaches the maximum,regardless if the magnetic field fully penetrates the superconductor or not. | XIA Jing ZHOU YouHe | 2014 | Science China(Technological Sciences)2014，57，4： | 5 |
| 7 | Methane dry reforming on Ni/La_2Zr_2O_7 treated by plasma in different atmospheres显示文摘A series of Ni/La2Zr2O7 pyrochlore catalysts prepared by impregnation method and treated by dielectric barrier discharge(DBD) plasma in different atmospheres and varied sequences were prepared and applied for dry reforming of methane(DRM). It is found that all of the plasma treated catalysts show evidently improved activity and coke resistance in comparison with the non-plasma treated one. The best performance is achieved on Ni/La2Zr2O7–H2P–C,a catalyst treated in H2 plasma before calcination. TGA-DSC and SEM demonstrate that carbon deposition is significantly suppressed on all of the plasma treated samples. Moreover,XRD and TEM results testify that both Ni O and Ni sizes on the calcined and reduced samples treated by plasma are also decreased,which results in higher Ni metal dispersion on the reduced and used catalysts and enhances the interactions between Ni sites and the support. It is believed that these are the inherent reasons accounting for the promotional effects of plasma treatment on the reaction performance of the Ni/La2Zr2O7 pyrochlore catalysts. | Honggen Peng Youhe Ma Wenming Liu Xianglan Xu Xiuzhong Fang Jie Lian Xiang Wang Changqing Li Wufeng Zhou Ping Yuan | 2015 | Journal of Energy Chemistry2015，24，4： | 4 |
| 8 | Wavelet solutions of Burgers' equation with high Reynolds numbers显示文摘A wavelet method is proposed to solve the Burgers’equation.Following this method,this nonlinear partial differential equation is first transformed into a system of ordinary differential equations using the modified wavelet Galerkin method recently developed by the authors.Then,the classical fourth-order explicit Runge–Kutta method is employed to solve the resulting system of ordinary differential equations.Such a wavelet-based solution procedure has been justified by solving two test examples:results demonstrate that the proposed method has a much better accuracy and efficiency than many other existing numerical methods,and whose order of convergence can go up to 5.Most importantly,our results also indicate that the present wavelet method can readily deal with those fluid dynamics problems with high Reynolds numbers. | LIU XiaoJing ZHOU YouHe ZHANG Lei WANG JiZeng | 2014 | Science China(Technological Sciences)2014，57，7： | 4 |
| 9 | A theoretical model of collision between soft-spheres with Hertz elastic loading and nonlinear plastic unloading显示文摘This paper presents a theoretical model on the normal(head-on) collision between soft-spheres on the basis of elastic loading of the Hertz contact for compression process and a nonlinear plastic unloading for restitution one,in which the parameters all are determined in terms of the material and geometric ones of the spheres,and the behaviors of perfect elastic,inelastic,and perfect plastic collisions appeared in the classical mechanics are fully described once a value of coefficient of restitution is specified in the region of 0 ≤ε≤ 1.After an empirical formula of the coefficient of restitution dependent on the impact velocity is suggested to fit the existing experimental measurements by means of the least square method,the predictions of the dependency and the collision duration are in well quantitative agreement with their experimental measurements.It is found that the measurable quantities are dependent on both the impact velocity and the parameters of spheres.Following this model,finally,an approach to determine the spring coefficient in the linear viscoelastic model of the collision is also displayed.These results obtained here will be significantly beneficial for the applications where a collision model is requested in the simulations of relevant grain flows and impact dynamics etc.. | Youhe Zhou 1,2,a) 1) Key Laboratory of Mechanics on Disaster and Environment in Western China,the Ministry of Education of China 2)Department of Mechanics and Engineering Science,College of Civil Engineering and Mechanics,Lanzhou University,Lanzhou 730000,China | 2011 | Theoretical & Applied Mechanics Letters2011，1，4： | 4 |
| 10 | APPLICATIONS OF WAVELET GALERKIN FEM TO BENDING OF PLATE STRUCTURE显示文摘A kind of calculating method for high order differentials expanded by the wavelet scal-ing functions and the integral of their product used in Galerkin FEM is proposed,so that we can usethe wavelet Galerkin FEM to solve boundary-value differential equations with orders higher than two.To combine this method with the Generalized Gaussian integral method in wavelet theory,we can findthat this method has many merits in solving mechanical problems,such as the bending of plates andthose with variable thickness.The numerical results show that this method is accurate. | Zhou Youhe Wang Jizeng Zheng Xiaojing | 1999 | Acta Mechanica Solida Sinica1999，12，2： | 4 |
| 11 | Frictional Behavior of a Micro-sized Superconducting Fiber in a Low-Temperature Medium: Experimental and Computational Analysis显示文摘 | Shiren La Jun Wang Xingyi Zhang Youhe Zhou | 2018 | Acta Mechanica Solida Sinica2018，31，4： | 3 |
| 12 | Effects of charged sand on electromagnetic wave propagation and its scattering field显示文摘Based on the Rayleigh’s scattering theory, the effects of sandstorms on the propagation of electromagnetic wave with different visibilities are presented by solving the scattering field of charged sand particles. Because of the electric charges on the sand surface, the theoretical attenuation will be large enough to match the measured value under certain conditions. And the results show that the effect of sand with electric charges all over its surface on electromagnetic wave attenuation is the same as that of sand without charge, which proves that electric charges distribute on partial surface of the sand in fact. | HE Qinshu ZHOU Youhe ZHENG Xiaojing | 2006 | Science China(Physics,Mechanics & Astronomy)2006，49，1： | 3 |
| 13 | Modeling of softsphere normal collisions with characteristic of coefficient of restitution dependent on impact velocity显示文摘This letter presents a theoretical model of the normal (head-on) collisions between two soft spheres for predicting the experimental characteristic of the coefficient of restitution dependent on impact velocity. After the contact force law between the contacted spheres during a collision is phenomenologically formulated in terms of the compression or overlap displacement under consideration of an elastic-plastic loading and a plastic unloading subprocesses, the coefficient of restitution is gained by the dynamic equation of the contact process once an initial impact velocity is input. It is found that the theoretical predictions of the coefficient of restitution varying with the impact velocity are well in agreement with the existing experimental characteristics which are fitted by the explicit formula. | Youhe Zhou | 2013 | Theoretical & Applied Mechanics Letters2013，3，2： | 3 |
| 14 | A WAVELET METHOD FOR BENDING OF CIRCULAR PLATE WITH LARGE DEFLECTION显示文摘A wavelet method for solving strongly nonlinear boundary value problems is described, which has been demonstrated early to have a convergence rate of order 4, almost independent of the nonlinear intensity of the equations. By using such a method, we study the bending problem of a circular plate with arbitrary large deflection. As the deflection increases,the bending behavior usually exhibits a so-called plate-to-membrane transition. Capturing such a transition has ever frustrated researchers for decades. However, without introducing any additional treatment, we show in this study that the proposed wavelet solutions can naturally cover the plate-membrane transition region as the plate deflection increases. In addition, the high accuracy and efficiency of the wavelet method in solving strongly nonlinear problems is numerically confirmed, and applicable scopes for the linear, the membrane and the von Karman plate theories are identified with respect to the large deformation bending of circular plates. | Xiaomin Wang Xiao jing Liu Jizeng Wang Youhe Zhou | 2015 | Acta Mechanica Solida Sinica2015，28，1： | 3 |
| 15 | A high-order accurate wavelet method for solving Schrdinger equations with general nonlinearity显示文摘A sampling approximation for a function defined on a bounded interval is proposed by combining the Coiflet-type wavelet expansion and the boundary extension technique. Based on such a wavelet approximation scheme, a Galerkin procedure is developed for the spatial discretization of the generalized nonlinear Schr¨odinger(NLS) equations, and a system of ordinary differential equations for the time dependent unknowns is obtained. Then, the classical fourth-order explicit Runge-Kutta method is used to solve this semi-discretization system. To justify the present method, several widely considered problems are solved as the test examples, and the results demonstrate that the proposed wavelet algorithm has much better accuracy and a faster convergence rate in space than many existing numerical methods. | Jiaqun WANG Xiaojing LIU Youhe ZHOU | 2018 | Applied Mathematics and Mechanics(English Edition)2018，39，2： | 3 |
| 16 | Creep effect on cellular uptake of viral particles显示文摘Receptor diffusion on cell membrane is usually believed as a major factor that controls how fast a virus can enter into host cell via endocytosis.However,when receptors are densely distributed around the binding site so that receptor recruiting through diffusion is no longer energetically favorable,we thus hypothesize that another effect,the creep deformation of cytoskeleton,might turn to play the dominant role in relaxing the engulfing process.In order to deeply understand this mechanism,we propose a viscoelastic model to investigate the dynamic process of virus engulfment retarded by the creep deformation of cytoskeleton and driven by the binding of ligand-receptor bonds after overcoming resistance from elastic deformation of lipid membrane and cytoskeleton.Based on this new model,we predict the lower bound of the ligand density and the range of virus size that allows the complete engulfment,and an optimal virus size corresponding to the smallest wrapping time.Surprisingly,these predictions can be reduced to the previous predictions based on simplified membrane models by taking into account statistical thermodynamic effects.The results presented in this study may be of interest to toxicologists,nanotechnologists,and virologists. | Jizeng Wang Long Li Youhe Zhou | 2014 | Chinese Science Bulletin2014，59，19： | 3 |
| 17 | Coiflet solution of strongly nonlinear p-Laplacian equations显示文摘A new boundary extension technique based on the Lagrange interpolating polynomial is proposed and used to solve the function approximation defined on an interval by a series of scaling Coiflet functions, where the coefficients are used as the single-point samplings. The obtained approximation formula can exactly represent any polynomials defined on the interval with the order up to one third of the length of the compact support of the adopted Coiflet function. Based on the Galerkin method, a Coiflet-based solution procedure is established for general two-dimensional p-Laplacian equations, following which the equations can be discretized into a concise matrix form.As examples of applications, the proposed modified wavelet Galerkin method is applied to three typical p-Laplacian equations with strong nonlinearity. The numerical results justify the efficiency and accuracy of the method. | Cong XU Jizeng WANG Xiaojing LIU Lei ZHANG Youhe ZHOU | 2017 | Applied Mathematics and Mechanics(English Edition)2017，38，7： | 2 |
| 18 | A method to access the electro-mechanical properties of superconducting thin film under uniaxial compression显示文摘Superconducting thin films are widely used in superconducting quantum interferometers,microwave devices,etc.The electrical performance of a superconducting thin film is often affected by structural deformation or stress.Based on four-point bending of a Cu-Be beam,we constructed a device that could apply uniaxial,uniform.compressive strain to a superconducting thin film at both room temperature and the temperature of liquid nitrogen.The thin film was placed into a slot carved in the Cu-Be beam.We optimized the size of this slot via numerical simulation.Our results indicated that the slot width was optimal when it was same as the width of the Cu-Be beam.Notably,the sample bended hardly after machining two slits along width direction on both sides of the slot.A YBa2Cu3O7-δSrTiO3(YBCO-STO)film was used as an example.It was loadedby the aforementioned device to determine its electrical characteristics as functions of the uniaxial-uniform-compressive strain.The optimized design allowed the sample to be compressed to a larger strain without breaking it. | Xiyang Su Cong Liu Jun Zhou Xingyi Zhang Youhe Zhou | 2020 | Acta Mechanica Sinica2020，36，5： | 2 |
| 19 | VIBRATION SUPPRESSION OF CANTILEVER LAMINATED COMPOSITE PLATE WITH NONLINEAR GIANT MAGNETOSTRICTIVE MATERIAL LAYERS显示文摘In this paper, a nonlinear and coupled constitutive model for giant magnetostrictive materials(GMM) is employed to predict the active vibration suppression process of cantilever laminated composite plate with GMM layers. The nonlinear and coupled constitutive model has great advantages in demonstrating the inherent and complicated nonlinearities of GMM in response to applied magnetic field under variable bias conditions(pre-stress and bias magnetic field).The Hamilton principle is used to derive the nonlinear and coupled governing differential equation for a cantilever laminated composite plate with GMM layers. The derived equation is handled by the finite element method(FEM) in space domain, and solved with Newmark method and an iteration process in time domain. The numerical simulation results indicate that the proposed active control system by embedding GMM layers in cantilever laminated composite plate can efficiently suppress vibrations under variable bias conditions. The effects of embedded placement of GMM layers and control gain on vibration suppression are discussed respectively in detail. | Yongfei Zhang Haomiao Zhou Youhe Zhou | 2015 | Acta Mechanica Solida Sinica2015，28，1： | 2 |
| 20 | Electromagnetic-thermal-structure multi-layer nonlinear elastoplastic modelling study on epoxy-impregnated REBCO pancake coils in high-field magnets显示文摘The elastoplastic mechanical behaviour of an epoxy-impregnated REBCO pancake winding under cryogenics and high magnetic field is investigated in the frame of finite element(FE)modelling.A two-dimensional axisymmetric electromagnetic-thermal-structure multi-physics multi-layer FE model with main layers of the coated conductor and insulation materials is developed.The radial stress and hoop stress on each constituent layer induced by thermal mismatch stress during cooling are investigated.The mechanical behaviour of each constituent material is also analysed by considering the thermal mismatch stress and electromagnetic force under 20 T background field.The results show that discrete stresses appear in all the constituent materials indicating that the multi-layer winding model containing the main constituent materials is necessary for the accurate stress analysis in an epoxy-impregnated REBCO winding.The stress of each constituent material induced by thermal mismatch during cooling process are too high to be ignored in the subsequent electromagnetic structure analysis.The mechanical-magnetic coupling analyses show that the stresses of all the constituent materials increase with the transport current.The plastic failure mainly induced by hoop stress successively occurs on copper stabilizer and Hastelloy substrate of the innermost turn,and the plastic region propagates from the inner turns to the outer turns with the increase of transport current.The failure of the superconducting layer occurs before the yield in Hastelloy due to the direct action of Lorentz force on the superconducting layers.The transverse tensile stress increases with the increasing transport current,indicating that the risk of transverse delamination failure increases with the increase of transport current.The mechanical failure modes including delamination within the conductor,plastic deformation in substrate and crack in superconducting layer should be seriously considered. | Peifeng Gao Mingzhi Guan Xingzhe Wang Youhe Zhou | 2022 | Superconductivity2022，，1： | 2 |
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