Home
|
About Journal
|
Editorial Board
|
Instruction
|
Subscriptions
|
Contacts Us
|
中文
Office Online
Submission Online
Peer Review
Editor Work
Editor-in-chief
Office Work
Journal Online
Accepted
Current Issue
Advanced Search
Archive
Read Articles
Download Articles
Email Alert
Quick Search
Adv Search
2013 Vol. 34, No. 5
Published:
论文
433
Mechanical Property Analysis and Structural Design of Flexible Skin Based on Deformable Honeycomb
Morphing aircraft can sufficiently change external shape for a best aerodynamic efficiency to adapt to a changing mission environment. The skin covering the aircraft structure should not only have a good in-plane flexibility to produce a smooth and continuous design deformation, but also provide adequate out-of-plane stiffness to maintain the aerodynamic configuration and deliver aerodynamic loads to the underlying structure. In this paper, a kind of flexible skin made up of the cruciform honeycomb overlying a silastic panel is proposed. The in-plane deformation mechanism of the flexible skin together with the effect of the cruciform honeycomb shape parameters on the mechanical property of the flexible skin are theoretically analyzed, and the analytical results are compared with the simulation and experimental results. According to the design requirements of the variable camber trailing edge wing, the optimized design parameters ranges of the flexible skin are given out. The results show that the flexible skin can provide enough in-plane deformation ability as well as out-of-plane bearing capacity satisfying the design requirements of the variable camber trailing edge wing.
2013 Vol. 34 (5): 433-440 [
Abstract
] (
410
)
HTML
(0 KB)
PDF
(0 KB) (
606
)
441
Research on the nonlinear magnetoelectric effect of layered ME composite cylinder shell
Based on the nonlinear constitutive relations of the giant magnetostrictive material, the nonlinear magnetoelectric(ME) effect of composite cylinder is considered. The influences of magnetic frequency and the thickness ratio of two materials on ME coefficient under different boundary conditions are discussed. Moreover, the effects of pre-pressure and magnetic field on the ME coefficient are obtained. For Tefernol-D/PZT-5 composite, with the increase of pre-pressure, the maximum value of ME coefficient decreased, but the magnetic field corresponding to the maximum value of ME coefficient increased. The result shows that the thickness ratio of two materials has significant effect on the ME coefficient of the giant magnetostrictive/piezoelectric composite cylinder. In addition, the mult-peak values of ME coefficient appear when the magnetic frequency is large.
2013 Vol. 34 (5): 441-449 [
Abstract
] (
260
)
HTML
(0 KB)
PDF
(0 KB) (
443
)
450
From cyclic hardening to cyclic softening: transforming of an ECAPed copper
In order to realize the influence of the ECAP (equal channel angular pressing) to cyclic properties of a material, the bar material of pure copper after multi-pass ECAP is chosen as a study subject and its mechanical behavior under uniaxial tension-compression cycle is investigated by experiment. This research is focus on the change of cyclic behavior of the copper after ECAP. According to the results and observes the conclusions are obtained: (1) The copper treated by ECAP may lead to the transform of cyclic properties from cyclic hardening to cyclic softening; (2) The first pass ECAP has the greatest effect on strengthening of the stress-strain response, the effectiveness of subsequent pass of ECAP will reduce severely and it can be regardless of that for subsequent pass after 4; (3) It has great difference by comparing the stress-strain response between the copper original and ECAPed. The monotonic uniaxial tension stress-strain curve is much higher than the cyclic stress-strain curve for the ECAPed copper, but it is on the contrary for the copper in original state. So it is necessary to evaluate mechanical properties strengthening by ECAP from both the monotonic and cyclic conditions simultaneously.
2013 Vol. 34 (5): 450-458 [
Abstract
] (
235
)
HTML
(0 KB)
PDF
(0 KB) (
469
)
459
PLASTIC DYNAMIC BUCKLING OF RECTANGULAR THIN PLATES SUBJECT TO IN-PLANE STEP LOAD
The critical stress and the exponential parameter of the buckling inertia term are treated as the twin characteristic parameters for the plastic dynamic buckling of rectangular thin plates subject to in-plane step load．The governing equations are derived by the adjacent-equilibrium criterion．The supplementary restraint condition of buckling deformation at the fronts of compression waves is obtained in terms of the criterion of transformation and conservation of energy in the transient process of dynamic buckling．The necessary and sufficient conditions of determining quantitatively the two characteristic parameters and buckling modes consist of stability equations，boundary conditions，continuity conditions at the front of plastic wave，and the supplementary restraint condition．In the dynamic buckling process of the rectangular thin plate, the relations of its thickness-width rate, the amplitude of impulsive loads, buckling modes and critical buckling length are studied．
2013 Vol. 34 (5): 459-465 [
Abstract
] (
277
)
HTML
(0 KB)
PDF
(0 KB) (
505
)
466
MODE I INTERLAMINAR FRACTURE TOUGHNESS FOR Z-PINS REINFORCED C/SiC COMPOSITES
2013 Vol. 34 (5): 466-472 [
Abstract
] (
262
)
HTML
(0 KB)
PDF
(0 KB) (
525
)
473
THE FRACTIONAL DERIVATIVE APPROACH TO CREEP CONSTITUTIVE MODEL OF SALT ROCK BASED ON WEIBULL DISTRIBUTION
A computer-controlled creep setup is applied to the triaxial creep tests of the salt rock specimens, which are taken from the Jianghan Oilfield, Hubei Province. Based on the definition of damage variable of rock, which is changing with loading time and obtained from Weibull distribution, a new variable-viscosity Abel dashpot has been proposed. Based on the theory of fractional calculus, the creep damage constitutive model of salt rock is proposed by replacing the Newtonian dashpot in the classical Nishihara model with the new Abel dashpot. Also, parameters in the new constitutive model can be determined by the least-squares fitting analysis. In comparison of fitted curves, it can be manifested that the fractional derivative creep constitutive model proposed in this paper is evidently superior to describe the three creep stages of salt rock, especially the tertiary one. Furthermore, the classical Nishihara model has been proved as a special case of the constitutive model proposed in this paper
2013 Vol. 34 (5): 473-480 [
Abstract
] (
384
)
HTML
(0 KB)
PDF
(0 KB) (
548
)
简报
481
Phase Field Modeling of Morphological Instability of Strained Heteroepitaxial Films on Wavy Substrates
This paper aims at investigating the surface nonlinear evolution behavior of strained heteroepitaxia -l films on wavy substrates. In this work, the phase field microelasticity model is used, which is based on the Eshelby’s equivalency approach, to simulate the morphological instability of the two-dimensional strained film/substrate system. The free energy functional with respect to the equivalent eigenstrain and the long-range order parameter was established and the two time-dependent Ginzburg-Landau kinetic equations were solved simultaneously. The system free energy comprises chemical energy, elastic strain energy and interfacial energy between film ,substrate and vacuum phase. The morphological evolution process was tracked and the profile of the quantum dots was given at some specific time. The results indicate that the quantum dots are inclined to form at the trough of the wavy substrate which is an energy preferable site and thus a more stable site than the crest. The profile, size and site of the quantum dots can be predicted by the phase field modeling in this paper, which can provide a guideline for controlling and producing periodic self-assembly surface nanostructures.
2013 Vol. 34 (5): 481-486 [
Abstract
] (
208
)
HTML
(0 KB)
PDF
(0 KB) (
707
)
487
Growth Issue of Void of Hyperelastic Electronic Packaging Materials Under Compressible Condition
The assumption of materials' incompressibility was amended to compressibility when the effect of temperature change on the volume of polymer materials was taken under consideration. Theoretical research is conducted on the popcorn void crack phenomenon of polymer materials with neo-Hookea feature under the effect of hygro-thermal during reflow soldering. Using the theory of finite deformation, an general analytical solution relating the void growth to the vapor presser and thermal stress is obtained when the temperature change cause the material volume change. The general analytical solution will include the analytical solution of the material with incompressibility. The analysis results show that：Considering the effect of volume expansion of polymer materials, the critical load will be increased. If the expansion coefficient is smaller, the effect of volume expansion on the evolution of the void will be less. Using the incompressible hypothesis is reasonable when the temperature variation range is small.
2013 Vol. 34 (5): 487-492 [
Abstract
] (
247
)
HTML
(0 KB)
PDF
(0 KB) (
605
)
493
RESEARCH ON RANDOM VIBRATION CONTROL THEORY OF SINGLE-DEGREE-OF-FREEDOM STRUCTURE WITH SUPERELASTIC SHAPE MEMORY ALLOY DAMPER
Using superelastic shape memory alloy (SMA) wire, a re-centring damper is presented. Based on the Graesser’s constitutive model of SMA wire, the slip bilinear restoring force model of the damper is set up. Given that the two models have the same hysteretic areas, a simplified slip rigid-plastic model is put forward to approximate the slip bilinear model. Using an equivalent linearization method, analyses of the stationary random vibration of a single-degree-of-freedom structure with the SMA damper subjected to a Gaussian white noise excitation are formulated. Numerical simulations are carried out, considering various excitation’s spectrum densities and damping ratios of the structure. Comparisons of the vibration responses (displacement standard deviation and velocity standard deviation) of the SMA-damped structure between the equivalent linearization method and the Monte Carlo simulation method testify the validity of the random vibration control theory. Comparisons of the dynamic properties (stiffness and damping ratio) and the vibration responses between the equivalent linearized damped structure and the uncontrolled structure prove that the SMA damper can decrease the structural vibration effectively attributed to its capabilities of increasing the stiffness and the damping ratio of the structure.
2013 Vol. 34 (5): 493-500 [
Abstract
] (
283
)
HTML
(0 KB)
PDF
(0 KB) (
435
)
501
EMISSION CRITERION OF A SCREW DISLOCATION FROM A SEMI-INFINITE WEDGE CRACK PENETRATING AN INHOMOGENEITY
Abstract: The interaction between a screw dislocation and a semi-infinite wedge crack penetrating a circular inhomogeneity is investigated. Using Riemann-Schwartz's symmetry principle integrated with the analysis of singularity of complex functions, the closed form solutions of the complex potentials in both the semi-infinite matrix and the semi-circular inhomogeneity are obtained when screw dislocation located in the semi-circular inhomogeneity. The expressions of stress fields in the inhomogeneity and the force acting on dislocation are derived by using the conformal mapping technique. The shielding effect and the emission criterion of the screw dislocation are discussed in detail. The results show that positive dislocation can reduce the stress intensity factor of the wedge crack and shield the crack growth. The shielding effect decreases with the increment of dislocation azimuth angle. The critical load at infinity for dislocation emission increases with the increment of emission angle, and the most probable angle for screw dislocation emission is zero. Comparing with the case for a straight-line crack, the emission of the dislocation from a wedge crack becomes more difficult. In addition, the hard matrix can enhance the critical load for the dislocation emission.
2013 Vol. 34 (5): 501-507 [
Abstract
] (
293
)
HTML
(0 KB)
PDF
(0 KB) (
575
)
508
Void evolution of micro/nanocrystalline Ni under uniaxial compression
To study the effect of pores on the mechanical properties of porous bulk micro/nanocrystalline Ni sample further, a model of pore evolution under uniaxial compression test was firstly established on the basis of the emission of geometrically necessary dislocations due to the mismatch between the pore and matrix. At the same time, a new constitutive relation considering the evolution of porosity under uniaxial compression was proposed, and the evolution of the porosity was described quantitatively. Then, the effects of constant porosity and evolution porosity on the mechanical behaviors of micro/nanocrystalline Ni with different grain sizes and strain rates were disscussed.
2013 Vol. 34 (5): 508-514 [
Abstract
] (
230
)
HTML
(0 KB)
PDF
(0 KB) (
390
)
515
THE INERTIA EFFECT OF THE COMPRESSIBLE CONCRETE MATERIAL TESTS IN SHPB SYSTEM
The inertia effect is one of the main sources to cause the stress nonuniformity and triaxial stress state in a concrete test utilizing the large-sized SHPB system. An improved Gorham’s inertia correction formula which could reflect the compressibility was derived in the light of a theoretical analysis on the regulation of the inertia effect. The improved formula was analyzed and validated by calculating the inertia stress based on the actual dynamic loading process of several concrete material tests. The results show that the improved formula is more comprehensive and reasonable for the consideration of the inertia effect.
2013 Vol. 34 (5): 515-520 [
Abstract
] (
266
)
HTML
(0 KB)
PDF
(0 KB) (
432
)
521
Time-delayed feedback control of the chaotic motion of the thin plate in subsonic air flow
The chaotic motion and its control of a two-dimensional simply supported thin plate with geometric nonlinearity subjected to subsonic air flow and transverse periodical load are studied. Based on von Karman’s plate theory and the variable separation method, the equation of motion of the thin plate under subsonic air flow is established. For the uncontrolled system, the Melnikov’s method is used to predict the threshold values for the chaotic motion, and the results are verified numerically through the Runge-Kutta method. For the system under chaotic motion, the time-delayed feedback control is used to control the chaotic motion of the plate. From the analytical and numerical results, it is shown that the Melnikov’s method is effective in estimating the threshold values for the chaotic motion, and the time-delayed feedback control method can effectively transform the chaotic motion of the plate into periodical one.
2013 Vol. 34 (5): 521-526 [
Abstract
] (
290
)
HTML
(0 KB)
PDF
(0 KB) (
498
)
536
AN ANALYSIS ON SATURATED SOIL FOUNDATION UNDER HARMONIC LOADS
In the framework of porous media model developed from mixtures theory, the dynamic response of incompressible soil foundation subjected harmonic loads is investigated by analytical method. General solutions of coupling equations are obtained using Fourier transform for two-dimensional saturated soil. In accordance with the boundary condition of ideal permeability at upper surface, integral forms solutions of solid displacement, fluid displacement, pore pressure and solid skeleton stress are presented. In addition, the dynamic response of a saturated layer under harmonic loads is researched by numerical example.
2013 Vol. 34 (5): 536-540 [
Abstract
] (
301
)
HTML
(0 KB)
PDF
(0 KB) (
451
)
News
Download
Download
Download
Links
Links
Copyright © Editorial Board of
Supported by:
Beijing Magtech
