含大量随机分布细小纤维的单向纤维增强复合材料横向弹性性能参数计算的内嵌区域模型法

利用有限元方法求取单向纤维增强复合材料的横向弹性性能参数的计算模型包括三维模型、两维平面应变模型、单胞模型等等.由于单胞模型仅仅适用于纤维规则排列情况.在纤维随机分布且纤维大小亦为随机时,单向纤维增强复合材料横向弹性性能参数必须通过对于复合材料块体的计算才能获得.同时在随机分布纤维的数量增大时,三维模型和二维平面应变模型的计算量急剧增加,模型的处理能力不强.该文提出一种利用内嵌区域模型来计算含大量随机大小、随机分布细小纤维的单向纤维增强复合材料块体的横向弹性性能参数的方法,有效降低了计算量.在较低的计算费用下,能够快速获得单向纤维增强复合材料的横向弹性性能参数.     

Fermions in light front transverse lattice quantum chromodynamics

We briefly describe motivations for studying transverse lattice QCD. Presence of constraint equation for fermion field on the light front allows different methods to put fermions on a transverse lattice. We summarize our numerical investigation of two approaches using (a) forward and backward derivatives and (b) symmetric derivatives.     

Elastic Deformation of Dispersely Failing Unidirectionally Reinforced Composites

A phenomenological model is proposed for describing the elastic deformation of a unidirectionally reinforced composite capable of accumulating scattered microdamages during its loading. The composite is considered as a homogeneous transversely isotropic solid. Its damaged state at every point is characterized by a centrally symmetric scalar function on the unit sphere (the damage function), which is used to account for variations in the elastic properties of the material during its deformation. The damage itself depends on the history of some equivalent strain, for which four simplified variants are suggested. The relation between strains and stresses is defined in a differential form. Dependences are presented for determining all unknown constants from simple mechanical experiments. As an example, an actual unidirectionally reinforced GFRP is considered, for which the main two-dimensional sections of corresponding failure surfaces are also constructed.     

On an Approach to the Solution of the Bending Problem for Laminated Plates

The paper presents a method for determining the three-dimensional state of stresses and strains in a moderately thick rectangular plate composed of isotropic layers unlimited in number and arranged symmetrically about the midplane of the plate. The method is based on a variant of Timoshenko theory [1, 2] and allows one to calculate the stresses and displacements in a shear-compliant plate for various types of boundary conditions and various external loads. According to it, the displacement field in the plate is represented as a sum of products of two unknown functions one of which is defined on the midplane and the second one depends on the thickness coordinate and satisfies the layer contact conditions. As an example, a rectangular laminated plate clamped at all its edges and loaded on the upper surface by a sinusoidal load is considered.     

Phase Diagram and Tricritical Behavior of a Spin-2 Transverse Ising Model in a Random Field

The phase diagrams of a spin-2 transverse Ising model with a random field on honeycomb, square, and simple-cubic lattices, respectively, are investigated within the framework of an effective-field theory with correlations.We find the behavior of the tricritical point and the reentrant phenomenon for the system with any coordination number z, when the applied random field is bimodal. The behavior of the tricritical point is also examined as a function of applied transverse field. The reentrant phenomenon comes from the competition between the transverse field and the random field.     

Bouncing Ball模型的弱混沌性

用异于传统的方法，作出Bouncing Ball映射不变流形的对称流形，从而成功地将稳定流形与不稳定流形的位置进行比较。应用[1]关于弱横截与弱混沌的有关概念及定理，给出了Borncing Ball映射产生弱混沌的较为一般的参数区域，进一步提示了Bouncing Ball映射的动力学行为。     

Global Classical Solutions to the Equations of Two-dimensional MHD Transverse Flow

A new method for constructing the symmetric form for the hyperbolic systems is introduced. Then a new symmetric form of the equations of MHD transverse flow is constructed by adding an additional equation. With this new form, we obtain the local existence of smooth solution including the case that the initial density may tend to the vacuum state at infinity. Furthermore, the uniformly a priori estimation for the classical solutions is established and the global smooth solutions for a kind of initial data are obtained.     

极化激元系统时间演化的量子涨落特性和非经典统计行为

将极化激元系统约化成模型单模光子-TO声子有效相互作用系统， 在此基础上以解析形式讨论了系统的力学量、压缩态、量子涨落特性以及亚泊松分布等非经典效应的动力学演化行为.结果表明，光子场与极化波量子场彼此交换能量过程随时间演化呈振荡性质，光子场和声子场都可以演化成压缩态，其二阶压缩度随时间演化成复杂周期振荡特性，这种非经典特性是非线性相互作用的结果并且以k₁项和k₂项同时存在并相互关联为前提.而此时光子和声子统计分布随时间演化呈现介于超Poison分布和亚Poison分布之间复杂周期振荡的新结果，非线性作用k₁项和k₂项对这种非经典统计行为都有贡献. 关键词： 极化激元系统动力学演化 单模光场-TO声子有效模型哈密顿量 量子涨落与压缩态 亚泊松分布     

衰减全反射磁镜偏频激光陀螺的理论分析

通过分析常规磁镜在红光波长下制造激光陀螺技术不可行的原因，提出了一种新型的磁镜偏频激光陀螺结构，其核心是利用全内反射结构和掺杂YIG薄膜的横向克尔磁光效应作为偏频技术去克服闭锁的衰减全反向磁镜。     

Influence of the orientation of the isotropy axis on the stability of transversely isotropic semibounded laminates

The surface-buckling problem for elastic transversely isotropic laminates is solved using the three-dimensional linearized theory of stability with the assumption of small prebuckling strains. The influence of the orientation of the isotropy axis on the critical parameters of the problem and the equilibrium state of the material is studied analytically and numerically __________ Translated from Prikladnaya Mekhanika, Vol. 42, No. 10, pp. 47–55, October 2006.