Assessing the Effects of Porosity on the Bending,Buckling, and Vibrations of Functionally Graded Beams Resting on an Elastic Foundation by Using a New Refined Quasi-3D Theory

Mechanics of Composite Materials - A new refined quasi-3D shear deformation theory for bending, buckling, and free vibration analyses of a functionally graded porous beam resting on an elastic...     

Free Vibration Analysis of Laminated Composite Plates Resting on Elastic Foundations by Using a Refined Hyperbolic Shear Deformation Theory

The free vibration of laminated composite plates on elastic foundations is examined by using a refined hyperbolic shear deformation theory. This theory is based on the assumption that the transverse displacements consist of bending and shear components where the bending components do not contribute to shear forces, and likewise, the shear components do not contribute to bending moments. The most interesting feature of this theory is that it allows for parabolic distributions of transverse shear stresses across the plate thickness and satisfies the conditions of zero shear stresses at the top and bottom surfaces of the plate without using shear correction factors. The number of independent unknowns in the present theory is four, as against five in other shear deformation theories. In the analysis, the foundation is modeled as a two-parameter Pasternak-type foundation, or as a Winkler-type one if the second foundation parameter is zero. The equation of motion for simply supported thick laminated rectangular plates resting on an elastic foundation is obtained through the use of Hamilton’s principle. The numerical results found in the present analysis for free the vibration of cross-ply laminated plates on elastic foundations are presented and compared with those available in the literature. The theory proposed is not only accurate, but also efficient in predicting the natural frequencies of laminated composite plates.     

Analysis of Mechanical Properties and a Design Method of Reinforced Timber-Concrete Composite Beams

Mechanics of Composite Materials - Based on the loading features of reinforced timber-concrete composite (TCC) beams, a calculation model of their ultimate flexural capacity is established. To...     

A Uniqueness Theorem in the Inverse Spectral Theory of a Certain Higher-Order Ordinary Differential Equation Using Paley-Wiener Methods

The paper examines a higher-order ordinary differential equationof the form where D = i(d/dx),and where the coefficients a_jk, j,k [0,m], with a_mm = 1, satisfycertain regularity conditions and are chosen so that the matrix(a_jk) is hermitean. It is also assumed that m > 1. More precisely,it is proved, using Paley–Wiener methods, that the correspondingspectral measure determines the equation up to conjugation bya function of modulus 1. The paper also discusses under whichadditional conditions the spectral measure uniquely determinesthe coefficients a_jk, j,k [0,m], j + k 2m, as well as b andthe boundary conditions at 0 and at b (if any).     

On Changes of Variable Preserving the Convergence and Absolute Convergence of Fourier Series in the Haar Wavelet System

Mathematical Notes - It is established that, among all continuously differentiable homeomorphic changes of variable, the absolute convergence of Fourier series in the Haar wavelet system is...     

线性映射方法在矩阵理论和运算中的应用

对矩阵的一些运算关系从映射角度考虑,得到概念上的新理解和运算的新技巧.特别是,给出了Frobenius不等式,Sylvester不等式等著名结果的极其简洁的证明,据此探讨了线性代数中有关问题和实例,包括列满秩矩阵的特点等.     

Modeling of Transverse Shears of Piecewise Homogeneous Composite Bars Using an Iterative Process with Account of Tangential Loads. 2. Resolving Equations and Results

Using the variational method, a system of resolving equations and boundary conditions is deduced on the basis of the nonclassical model for a composite bar. The order of the equations depends on the step of the iterative process. For normal and tangential loads, these equations are realized in trigonometric series. The results are presented as a sum of the classical solution and an additional part, which is determined by the influence of the shear deplanation of cross sections and is taken into account by higher iterations. The problems for bars with various cross section variants are considered.     

基于HIS和小波变换相结合的图像融合方法

分析了HIS变换在图像融合中产生颜色失真的原因,提出了将HIS变换和小波变换相结合的方法,有效地解决了融合中颜色失真的问题,并根据融合评价体系对实验结果进行评价.结果显示,方法与传统的HIS方法相比取得了更好的融合效果.     

采用新方法研究非局部理论中Ⅰ-型裂纹的断裂问题

采用新的方法研究非局部理论中Ⅰ_型裂纹的断裂问题,进而确定裂纹尖端的应力状态,这种方法就是Schmidt方法·　所得结果比艾林根研究同样问题的结果准确和更加合理,克服了艾林根研究同样问题时遇到的数学困难·　与经典弹性解相比,裂纹尖端不再出现物理意义上不合理的应力奇异性,并能够解释宏观裂纹与微观裂纹的力学问题·     

Experimental and Numerical Study of the Static Performance of a Hoop-Wrapped CNG Composite Cylinder Considering Its Variable Wall Thickness and Polymer Liner

Mechanics of Composite Materials - The static performance of a composite type 4 CNG cylinder was investigated using a finite-element simulation and experimental validation. This cylinder involved a...     

Restricted Normal Cones and the Method of Alternating Projections: Theory

In this paper, we introduce and develop the theory of restricted normal cones which generalize the classical Mordukhovich normal cone. We thoroughly study these objects from the viewpoint of constraint qualifications and regularity. Numerous examples are provided to illustrate the theory. This work provides the theoretical underpinning for a subsequent article in which these tools are applied to obtain a convergence analysis of the method of alternating projections for nonconvex sets.