We study buckling of inhomogeneous plates on a nonlinear elastic foundation. First we construct the elastic energy of a thin, compressively loaded inhomogeneous plate in which Young's modulus depends only on its thickness direction with the power law of the coordinate variable. Next we develop the linear stability analysis around the prebuckling state and derive the critical load and wavelength. Effects of material inhomogeneity on the critical state are discussed with the dispersion relation.

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Theoretical analysis for thermally induced vibration of an inhomogeneous rectangular plate is treated in this study. It is assumed that material properties of the plate are given by the power product form with coordinate z'. Firstly, the one-dimensional transient heat conduction problem of the plate is developed when it is subjected to cyclic heating. Then, the thermally induced vibration for the plate is analyzed under the condition that all edges are to be simply supported in such a manner that the in-plane displacements are fully restrained. Next, numerical calculations are carried out, and we discussed about an effect of aspect ratio on thermal displacements, thermal stresses and resonance characteristic in the plate.

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This paper presents design of planner structure using local rule. We have the aim to make the structure that has uniform stress in whole structure. Finite element method is used to solve the two-dimensional elastic problem. Four-node, rectangular element is used. The structure is updated by changing the density parameter of each cell. The density parameter is changed by the equivalent stress, and if the density parameter of any cell attains the lower limit value, the cell is removed. Repeating calculation, we obtain the structure that has uniform stress in whole structure.

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This paper is concerned with the theoretical treatment of transient thermoelastic problem of an angle-ply laminated cylindrical shell due to axisymmetrical heat supply. We analyze the transient thermoelastic problem of an angle-ply laminated cylindrical shell under a simply supported condition. Some numerical results for the temperature change,the displacements and the stresses from the early stage of the heating to the steady state are investigated.

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This paper deals with the stress concentration problems of an elastic semi-infinite plate with a circular hole under a concentrated load acting on the straight edge. A body force distribution method of solution is presented for the problem by applying the so-called Melan's solution for a point body force acting in an elastic semi-infinite plate. Influences of the depth of the circular hole and the position of the concentrated load on stress distributions are investigated.

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Nano-structural control of CNT/epoxy composite by alternative electric field was investigated in terms of applied voltage and frequency. A mixture of CNT and epoxy without hardener was observed by optical microscope under AC field. As a result, it is found that lower applied voltage just makes CNTs align in the electric field direction, but higher applied voltage forms CNT network. The critical voltage to form the network depends on the volume fraction of CNT. Applied voltage and frequency affect the morphology of the CNT network. In addition, a CNT/epoxy composite plate was cured under AC field to confirm the feasibility of nano-structural control by AC electrical field. SEM observation shows that unidirectional alignment in the thickness direction was achieved by AC electrical field.

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In the present article, we deal with spherically symmetric isothermal and thermo elastic problems of a transversely isotropic, inhomogeneous hollow sphere, analytically. We assume that material properties such as the thermal conductivities, the Young's moduli and the coefficients of linear thermal expansion are independently varied in a form of power with radial coordinate γ, and that they also have same properties in θ-φ plane whereas those in the radial direction differ from those in θ-φ plane. We formulate the equation of heat conduction in a steady state and the displacement equation of equilibrium for the hollow sphere under spherically symmetric condition. Thereafter we derive analytical solutions of displacement and stress components for the hollow sphere which is subject to uniform pressures or uniform heat supply at inner and outer boundary surfaces. We carry out numerical calculation and discuss the effect of interaction between material anisotropy and material inhomogeneity on the mechanical behavior of the hollow sphere.

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In the present article, we deal with a plane axisymmetric isothermal elastic problem of a cylindrically anisotropic, inhomogeneous hollow circular plate, analytically. We assume that the Young's moduli and the mass density are independently varied in a form of power with radial coordinate γ, and that the Young's moduli also have cylindrically anisotropic properties. We formulate the displacement equation of equilibrium for the hollow circular plate under a plane axisymmetric condition. Thereafter we derive analytical solutions of displacement and stress components for the hollow circular plate which is subject to a centrifugal force caused by the rotation at a constant angular velocity about a central axis. We carry out numerical calculation and discuss the effect of interaction between material anisotropy and material inhomogeneity on the mechanical behavior of the hollow circular plate.

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This paper investigates on the stress concentrations of an elastic infinite plate with a circular hole under two harmonic vibration loads. In the first report, we have presented a dynamic body force distribution method for the problem under a harmonic vibration load. In this paper, we assume that the two harmonic vibration loads act on the symmetrical points of a straight line passing through a central point of the circular hole. Stress concentrations around the hole are shown.

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In the previous paper, we proposed harmonic displacement potentials method in the thin elastic plate theory. Then we can solve complicated multi-connected domain problems. In the present paper, we prsent an analytic solution for an elastic strip containing an elliptic inclusion under transverse bending at infinity.

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This paper deals with the centrifugal stresses of a rotating circular elastic disk with a rigid circular axis. For a rotating circular hollow disk with no rotating axis, an approximate analytical solution is known. Using the approximate solution, we present a method of solution for three dimensional stresses of a rotating disk with a rigid rotating axis. An integral equation is formulated for the problem using Green's functions for axisymmetric body force problems of an infinite elastic plate. The centrifugal stress distributions are shown by numerical calculations.

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This paper deals with the stress concentration problems of an infinite elastic plate with a rigid circular inclusion under in-plane shear loading. It is assumed that there are partially debonded boundary at the interface. In a previous paper, a method of solution was presented for the problem by using a fundamental solution for two point body forces. In this paper, we use a fundamental solution for four point body forces. Stress distributions at the interface are shown and the stress singularities at the tip of debonded interface are discussed.

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We analyze a magnetothermoelastic problem of the conducting circular plate which is subject to sinusoidal time variation of magnetic flux in the thickness direction. We obtain the analytical solutions of eddy current density, temperature change, displacement, and stresses in the plate under the plane axisymmetric condition. Performing numerical calculation, we discuss the effects of the frequency in magnetic flux and relative heat transfer coefficients at boundary surfaces on temperature change, displacement and stresses of the plate.

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In this study, the theoretical analysis of transient piezothermoelasticity is developed for a smart composite strip bounded to a functionally graded piezoelectric layer (FGPL), subject to nonuniform heat supply in the width direction. Using the analytical procedure of a laminated composite strip model, we obtain the solution for the two-dimentional temperature change in a transient state, and piezothermoelasticity of simply supported combined strip under the state of plane strain. Some numerical results for the temperature change, the displacement, the stress, and electric potential distributions when the thermoelastic displacement is not controlled or controlled are shown in figures.

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The effect of temperature environmental condition on the mechanical behavior of basalt fiber reinforced polymer (BaFRP) composites is investigated. Basalt fiber made from basalt rocks is one of the eco-friendly materials. From the experimental results for Ba/Phenol composites, the laminate kept in high temperature condition has lower tensile strength and equivalent Young's modulus than that in the room temperature condition of 298K. It is revealed that the diameters of basalt fiber manufactured vary widely and the stochastic consideration might be needed in order to predict the mechanical properties of Ba/Phenol composites theoretically. By using a model for microstructure of the composites, a homogenization theory with multi-scale asymptotic expansion is adopted to examine the macro- and microscopic behavior of the composites in the environmental conditions theoretically.

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When a sphere is heated instantaneously axisymmetrically on its surface, thermal stress waves occur at the surface of the sphere. The stress waves in a sphere proceed radially inward to the center of the sphere. The waves may accumulate at the center and give rise to very large stress magnitudes, even through the initial thermal stress is relatively small. This phenomenon is called the stress-focusing effect, In this study we apply the thermal stress-focusing effect to a thermic laser detector. The distinctive feature of this detector is high sensing speed, high sensitivity, and compact structure. The experimental results give a clear indication of the mechanism of a detector.

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The classical body-force analogy for static problems of thermoelasticity is extended towards generalized thermoelastic problems. We consider two dynamic problems, namely a thermal problem without body forces, but with a given distribution of transient sources of heat, and a force problem without sources of heat, but with body forces. Both problems are treated within the theory of generalized thermoelasticity, such that thermal wave speed must be finite. We restrict our considerations to the one-dimensional case, and we show that, given suitable boundary and initial conditions, a distribution of body forces can be constructed, such that the dynamic displacements or transient temperature in both problems become equal. This analogy is checked by means of illustrative analytical examples.

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This paper is concerned with a numerical solutions for one-dimensional thermal and mechanical waves in a thin elastic plate subjected to impulsive surface heating. The formulation of the problem is based on the dynamic theory of coupled thermoelasticity along with the modified Fourir's law. The damping in the inertia term is also considered. The numerical procedure employs the characteristic method based on the integration of the characteristic equations along the characteristics. The numerical results are shown in the graphical form.

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Considering a defect to be a notch filled with an electrical inclusion, path-independent integral expression of CED in arbitrary direction and its each mode contributions for piezoelectric material was derived first. Subsequently, relation between CED in arbitrary direction and energy release rate is clarified and their approximate expression is derived by employing the singular solution around crack tip. By using ε^<MI>_ψ and ε^<MII>_ψ, mode I and mode II contributions of mechanical CED in arbitrary direction, as crack parameters, effects of electric field and crack surface boundary conditions on ε^<MI>_ψ and ε^<MII>_ψ are discussed.

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In this paper, constitutive equation to describe electric yielding behavior of a piezoelectric material is given out first. Then, the characteristics of ε_J-integral, that is, path-independent expression of CED when electric yielding is considered are discussed and, in the light of ε_J-integral, the physical meaning and applicable ranges of J-integral is clarified. Finally, how electric yielding influences fracture load estimation is fundamentally studied.

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Mechanical CED (Crack Energy Density) has been proposed as a parameter to describe fracture behavior of piezoelectric materials. In this paper, we show that it depends on the loading procedure, while the whole CED does not. Then, we evaluate fracture loads corresponding to experiments for PZT-4 by employing the fracture criterion based on mechanical CED and fundamentally study the effects of loading procedure on fracture load comparing the results with the experiment.

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