当期目录

2015年 第36卷 第4期    刊出日期：2015-04-01

上一期    下一期

Three-dimensional elastostatic solutions for transversely isotropic functionally graded material plates containing elastic inclusion

Bo YANG;Weiqiu CHEN;Haojiang DING

2015, 36(4):  417-426.  doi:10.1007/s10483-015-1950-9

摘要 ( 659 )   HTML   PDF (114KB) ( 370 )  

参考文献 | 相关文章 | 多维度评价

Based on the generalized England-Spencer plate theory, the equilibrium of a transversely isotropic functionally graded plate containing an elastic inclusion is studied. The general solutions of the governing equations are expressed by four analytic functions α(ζ), β(ζ), φ(ζ), and ψ(ζ) when no transverse forces are acting on the surfaces of the plate. Axisymmetric problems of a functionally graded circular plate and an infinite func-tionally graded plate containing a circular hole subject to loads applied on the cylindrical boundaries of the plate are firstly investigated. On this basis, the three-dimensional (3D) elasticity solutions are then obtained for a functionally graded infinite plate containing an elastic circular inclusion. When the material is degenerated into the homogeneous one, the present elasticity solutions are exactly the same as the ones obtained based on the plane stress elasticity, thus validating the present analysis in a certain sense.

Analytic elasticity solution of bi-modulus beams under combined loads

Huiling ZHAO;Zhiming YE

2015, 36(4):  427-438.  doi:10.1007/s10483-015-1922-9

摘要 ( 710 )   HTML   PDF (377KB) ( 229 )  

参考文献 | 相关文章 | 多维度评价

A unified stress function for bi-modulus beams is proposed based on its mechanic sense on the boundary of beams. Elasticity solutions of stress and displacement for bi-modulus beams under combined loads are derived. The example analysis shows that the maximum tensile stress using the same elastic modulus theory is underestimated if the tensile elastic modulus is larger than the compressive elastic modulus. Otherwise, the maximum compressive stress is underestimated. The maximum tensile stress using the material mechanics solution is underestimated when the tensile elastic modulus is larger than the compressive elastic modulus to a certain extent. The error of stress using the material mechanics theory decreases as the span-to-height ratio of beams increases, which is apparent when L/h ≤5. The error also varies with the distributed load patterns.

论文

Three-dimensional free vibration analysis of multi-directional functionally graded piezoelectric annular plates on elastic foundations via state space based differential quadrature method

M. H. YAS;N. MOLOUDI

2015, 36(4):  439-464.  doi:10.1007/s10483-015-1923-9

摘要 ( 799 )   HTML   PDF (663KB) ( 292 )  

参考文献 | 相关文章 | 多维度评价

The three-dimensional free vibration analysis of a multi-directional functionally graded piezoelectric (FGP) annular plate resting on two parameter (Pasternak) elastic foundations is investigated under different boundary conditions. The material properties are assumed to vary continuously along the radial and thickness directions and have exponent-law distribution. A semi-analytical approach named the state space based differential quadrature method (SSDQM) is used to provide an analytical solution along the thickness using the state space method (SSM) and an approximate solution along the radial direction using the one-dimensional differential quadrature method (DQM). The influence of the Winkler and shear stiffness of the foundation, the material property graded variations, and the circumferential wave number on the non-dimensional natural frequency of multi-directional FGP annular plates is studied.

Investigation on behavior of crack penetration/deflection at interfaces in intelligent coating system

Yang SUN;Wenjuan WANG;Binbin LI;Mabao LIU

2015, 36(4):  465-474.  doi:10.1007/s10483-015-1921-9

摘要 ( 646 )   HTML   PDF (3997KB) ( 169 )  

参考文献 | 相关文章 | 多维度评价

Based on the three-phase model, the propagation behavior of a matrix crack in an intelligent coating system is investigated by an energy criterion. The effect of the elastic mismatch parameters and the thickness of the interface layer on the ratio of the energy release rate for infinitesimal deflected and penetrated crack is evaluated with the finite element method. The results show that the ratio of the energy release rates strongly depends on the elastic mismatch α₁ between the substrate and the driving layer. It also strongly depends on the elastic mismatch α₂ between the driving layer and the sensing layer for a thinner driving layer when a primary crack reaches an interface between the substrate and the driving layer. Moreover, with the increase in the thickness of the driving layer, the dependence on α₂ gradually decreases. The experimental observation on aluminum alloys monitored with intelligent coating shows that the established model can better explain the behavior of matrix crack penetration and can be used in optimization design of intelligent coating.

Analytic calculation of magnetic force between two current-carrying coils

Xiaofan GOU;Jian QIN

2015, 36(4):  475-486.  doi:10.1007/s10483-015-1924-9

摘要 ( 843 )   HTML   PDF (1360KB) ( 156 )  

参考文献 | 相关文章 | 多维度评价

Current-carrying coils are basic elements in electromagnetic equipments, for example, in high field magnets from high temperature superconducting wires or tapes. In the assembly of these systems and their current-carrying operation, unavoidable mis-alignment and shift from the original position can be induced by disturbances such as the imbalance of magnetic force due to safety problems. For two current-carrying coils with non-coplanar axes, the analytic expression of the magnetic force between the two coils is presented according to the rule of Ampere circulation and the Biot-Savart law. Based on the expression, the dependence of the magnetic force on the size and the relative position of each other is further investigated, and the variation of the magnetic force is obtained with the above parameters.



Study of microstructure and flexural properties of microcellular acrylonitrile-butadiene-styrene nanocomposite foams: experimental results

A. MOHYEDDIN;A. FEREIDOON;I. TARAGHI

2015, 36(4):  487-498.  doi:10.1007/s10483-015-1925-9

摘要 ( 558 )   HTML   PDF (18017KB) ( 89 )  

参考文献 | 相关文章 | 多维度评价

In this paper, acrylonitrile-butadiene-styrene (ABS) nanocomposite foams are produced using carbon dioxide through the solid-state batch process. Microcellular closed-cell foams are produced with the relative density ranging from 0.38 to 0.97. The effects of the processing conditions on the density, morphology, and flexural properties of ABS and its nanocomposite foams are studied. It is found that nanoclay particles, as nucleating sites, play an important role in reducing the size of cells and increasing their number in the unit volume of foamed polymer, as well as increasing the flexural modulus of foam through reinforcing its matrix.

Heat transfer analysis in peristaltic flow of MHD Jeffrey fluid with variable thermal conductivity

Q. HUSSAIN;S. ASGHAR;T. HAYAT;A. ALSAEDI

2015, 36(4):  499-516.  doi:10.1007/s10483-015-1926-9

摘要 ( 807 )   HTML   PDF (1252KB) ( 667 )  

参考文献 | 相关文章 | 多维度评价

null

Rotation invariant constitutive relation for Reynolds stress structure parameter

Jinglei XU;Zhengguang TU;Ning HU

2015, 36(4):  517-522.  doi:10.1007/s10483-015-1927-9

摘要 ( 667 )   HTML   PDF (582KB) ( 121 )  

参考文献 | 相关文章 | 多维度评价

A new Reynolds stress constitutive formula is constructed using the first-order statistics of turbulent fluctuations instead of the mean strain rate. It includes zero empirical coefficients. The formula is validated with the direct numerical simulation (DNS) data of turbulent channel flow at Re_τ=180. The Reynolds stresses given by the proposed formula agree very well with the DNS results. The good agreement persists even after the multi-angle rotation of the coordinate system, indicating the rotation in-variance of the formula. The autocorrelation of the fluctuating velocity rather than the mean strain rate is close to the essence of the Reynolds stress.

Lattice Boltzmann simulation of natural convection in open end cavity with inclined hot wall

M. NAZARI;H. SHOKRI;A. A. MOHAMAD

2015, 36(4):  523-540.  doi:10.1007/s10483-015-1928-9

摘要 ( 954 )   HTML   PDF (1639KB) ( 334 )  

参考文献 | 相关文章 | 多维度评价

Natural convection in an open end cavity with a hot inclined wall is simulated based on the lattice Boltzmann method (LBM). The physics of flow and energy transfer in open end cavities are addressed when the hot wall is inclined. The combination of the two topics (open cavity and inclined walls) is the main novelty of the present study. The effects of the angle of the hot inclined wall on the flow field and heat transfer are thoroughly investigated. The Prandtl number is fixed to 0.71 (air). The Rayleigh number and the angle of the hot inclined wall are varied in the range of 10⁴ to 10⁶ and 60? to 85?, respectively. The results are presented for two different aspect ratios, i.e., A = 1 and 2. The results obtained with the LBM are also compared with those of the finite volume method (FVM). The predicted results of the LBM conform to those of the FVM. The results show that by increasing the angle of the hot inclined wall and the aspect ratio of the cavity, the average Nusselt number decreases. The trend of the local Nusselt number on the inclined wall is also discussed.

Exactness of penalization for exact minimax penalty function method in nonconvex programming

T. ANTCZAK

2015, 36(4):  541-556.  doi:10.1007/s10483-015-1929-9

摘要 ( 573 )   HTML   PDF (166KB) ( 177 )  

参考文献 | 相关文章 | 多维度评价

The exact minimax penalty function method is used to solve a noncon-vex differentiable optimization problem with both inequality and equality constraints. The conditions for exactness of the penalization for the exact minimax penalty function method are established by assuming that the functions constituting the considered con-strained optimization problem are invex with respect to the same function η (with the exception of those equality constraints for which the associated Lagrange multipliers are negative—these functions should be assumed to be incave with respect to η). Thus, a threshold of the penalty parameter is given such that, for all penalty parameters exceeding this threshold, equivalence holds between the set of optimal solutions in the considered constrained optimization problem and the set of minimizer in its associated penalized problem with an exact minimax penalty function. It is shown that coercivity is not suf-ficient to prove the results.