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991.
基于可动边界变分原理对层合梁脱层扩展进行了分析;考虑了脱层间的接触效应,建立了层合梁在横向线载荷作用下的非线性控制微分方程及相应的定解条件;应用Griffith准则导出了脱层前缘各点处的能量释放率表达式;通过算例讨论了脱层长度、脱层深度、几何尺寸、材料性质等因素对脱层扩展的影响.研究表明:脱层越长、越深、横向载荷越大,脱层越容易扩展;梁的长高比L/h及材料的E_(11)/E_(22)越大,脱层越不易发生扩展. 相似文献
992.
The co-evolutionary dynamics of a cyclic game system is investigated in a two-dimensional square lattice with the asymmetrical rates for three species. Different with the well-mixed system, coexistence and extinction emerge alternately in the system, where a "zero-one" behavior is robust for a small population size, whereas, the system is predominated by coexistence for a big population one. We study in detail the influence about the fluctuation to the change of the state, and find that the difference between the maximal amplitude about the fluctuation and the average intensity determines which state the system is ultimately. In addition, we introduce Ports energy to explain the reason of the "zero-one" behavior. It is shown that the average Ports energy per site is the distance to the "zero-one" behavior in the model. 相似文献
993.
Effect of unequal injection rates and different hopping rates on asymmetric exclusion processes with junction 下载免费PDF全文
In this paper, the effects of unequal injection rates and different hopping rates on the asymmetric simple exclusion process (ASEP) with a 2-input 1-output junction are studied by using a simple mean-field approach and extensive computer simulations. The steady-state particle currents, the density profiles, and the phase diagrams are obtained. It is shown that with unequal injection rates and different hopping rates, the phase diagram structure is qualitatively changed. The theoretical calculations are in good agreement with Monte Carlo simulations. 相似文献
994.
S. N. Korobeynikov 《Journal of Elasticity》2008,93(2):105-140
Following Ogden, a class of objective (Lagrangian and Eulerian) tensors is identified among the second-rank tensors characterizing
continuum deformation, but a more general definition of objectivity than that used by Ogden is introduced. Time rates of tensors
are determined using convective rates. Sufficient conditions of objectivity are obtained for convective rates of objective
tensors. Objective convective rates of strain tensors are used to introduce pairs of symmetric stress and strain tensors conjugate
in a generalized sense. The classical definitions of conjugate Lagrangian (after Hill) and Eulerian (after Xiao et al.) stress and strain tensors are particular cases of the definition of conjugacy of stress and strain tensors in the generalized
sense used in the present paper. Pairs of objective stress and strain tensors conjugate in the generalized sense are used
to formulate constitutive relations for a hyperelastic medium. A family of objective generalized strain tensors is introduced,
which is broader than Hill’s family of strain tensors. The basic forms of the hyperelastic constitutive relations are obtained
with the aid of pairs of Lagrangian stress and strain tensors conjugate after Hill (the strain tensors in these pairs belong
to the family of generalized strain tensors). A method is presented for generating reduced forms of the constitutive relations
with the aid of pairs of Lagrangian and Eulerian stress and strain tensors conjugate in the generalized sense which are obtained
from pairs of Lagrangian tensors conjugate after Hill by mapping tensor fields on one configuration of a deformable body to
tensor fields on another configuration.
相似文献
995.
戴天民 《应用数学和力学(英文版)》2000,21(3):249-254
IntroductionIn[1]therelationsofvariousstresstensors,theequationsofmomentumandthecorrespondingboundaryconditionsofvariousformsforclassicalcontinuummechanicsaresystematicallyderived.In[2]thegeneralizedcontinuumfieldtheoriesarecomprehensivelyreviewedandclar… 相似文献
996.
极性连续统的增率型运动方程和边界条件 总被引:5,自引:3,他引:2
推导出了各种偶应力张量间和它们的变率间的关系,并建立起增率型角动量方程及其相应的边界条件。于是,把这些结果和匡震邦在“非线性连续介质力学基础”中给出的经典连续统力学的相应结果组合起来即得Cauchy形式和Piola形式以及Kirchhoff形式的极性连续统的增率型运动方程和边界条件。 相似文献
997.
Three kinds of queues with Markovian arrival process and/or Markovian service process, are considered in this paper. In great generality, their basic steady-state distributions have asymptotically exponential tails. We investigate the sensitivity of these asymptotic decay rates to the small entrywise perturbations in the parameter matrices of the Markovian arrival process. 相似文献
998.
Bryan P. Rynne 《Advances in Computational Mathematics》2000,12(2-3):251-259
In this paper we consider the Pocklington integro–differential equation for the current induced on a straight, thin wire by an incident harmonic electromagnetic field. We show that this problem is well posed in suitable fractional order Sobolev spaces and obtain a coercive or Gårding type inequality for the associated operator. Combining this coercive inequality with a standard abstract formulation of the Galerkin method we obtain rigorous convergence results for Galerkin type numerical solutions of Pocklington's equation, and we demonstrate that certain convergence rates hold for these methods. 相似文献
999.
T. Mančal V. May 《The European Physical Journal B - Condensed Matter and Complex Systems》2000,18(4):633-643
Non-Markovian dynamics in open quantum systems is characterized by a time-non-locality in the equation of motion valid for
the reduced density operator. An expansion of this density matrix equation with respect to Laguerre polynomials is used to
tackle the time-non-locality. The applicability and the numerical limitations of the method are discussed in detail. In order
to illuminate the characteristics of non-Markovian dynamics the reference example is studied of a single quantum degree of
freedom moving in a harmonic potential and being embedded in a heat bath. If interpreted as the photoinduced dynamics of nuclear
motion in polyatomic molecules we can suggest two clear signatures of non-Markovian dynamics observable in ultrafast optical
experiments, firstly a pronounced and somewhat irregular oscillatory behavior of the vibrational level populations, and secondly
a separation of the vibrational wavepacket into a double-structure.
Received 12 April 2000 and Received in final form 2 September 2000 相似文献
1000.
Superelastic polycrystalline NiTi shape memory alloys under tensile loading accompany the strain localization and propagation phenomena. Experiments showed that the number of moving phase fronts and the mechanical behavior are very sensitive to the loading rate due to the release/absorption of latent heat and the material’s inherent temperature sensitivity of the transformation stress. In this paper, the moving heat source method based on the heat diffusion equation is used to study the temperature evolution of one-dimensional superelastic NiTi specimen under different loading rates and boundary conditions with moving heat sources or a uniform heat source. Comparisons of temperature variations with different boundary conditions show that the heat exchange at the boundaries plays a major role in the nonuniform temperature profile that directly relates to the localized deformation. Analytical relation between the front temperature of a single phase front, the inherent Clausius–Clapeyron relation (sensitivity of the material’s transformation stress with temperature), heat transfer boundary conditions and the loading rate is established to analyze the nucleation of new phase fronts. Finally, the rate-dependent stress hysteresis is also simply discussed by using the results of temperature analyses. 相似文献