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1.
Summary In this paper, we study a two-dimensional electroelastic problem of an infinite piezoelectric body with two circular piezoelectric
inhomogeneities, one of which contains a crack. We formulate the stress intensity factor (SIF) analytically and investigate
it numerically. The problem is solved based on Bueckner's principle, and is reduced to a problem of a singular integral equation
of the first kind with respect to the distribution function of screw dislocation. The effect of interaction between the two
inhomogeneities and the crack on the electroelastic field as well as the control of the SIF by electrical loads is investigated.
Received 18 April 2000; accepted for publication 24 October 2000 相似文献
2.
Summary A piezoelectric layer bonded to the surface of an elastic structure is considered. The piezoelectric and the elastic layers
are infinite along the x-axis and have finite thickness in the y-direction. The polarization direction of the piezoelectric material is along the y-axis. By means of the method of singular integral equations, the solution in a Laplace transform plane is demonstrated. Laplace
inversion yields the results in the time domain. Numerical values of the crack tip fields under in-plane transient electromechanical
loading are obtained. The influence of layers thickness on stress and electric displacement intensity factors is investigated.
Received 16 March 2000; accepted for publication 16 August 2000 相似文献
3.
J. J. Golecki J. D. Suzdalnitsky 《Archive of Applied Mechanics (Ingenieur Archiv)》2001,71(9):640-648
Summary Under external forces acting on the face of a notch, cracks originate at corners, and the system is liable to fail. An analysis
is presented of the stress field in the neighborhood of the notch tips, based on the integral representation of the biharmonic
solution and on numerical methods. Computations were performed for constant loading or constant displacement distributed along
one face of the notch. The coefficients in the principal terms of the asymptotic formulae for the circumferential and shear
stresses depend on the angle and height of the notch face and on the boundary conditions. The maximal values of these coefficients
determine the stress intensity factors for the opening and shear modes. The angles corresponding to the maximal values of
the intensity factors indicate the directions of initiation of opening and sliding cracks.
Received 30 May 2000; accepted for publication 3 April 2001 相似文献
4.
Electro-mechanical analysis of an interfacial crack between a piezoelectric and two orthotropic layers 总被引:1,自引:0,他引:1
Summary The problem of an interfacially cracked three-layered structure constructed of a piezoelectric and two orthotropic materials
is analyzed using the theory of linear piezoelectricity and fracture mechanics. Anti-plane shear loading is considered, and
the integral transform technique is used to determine the stress intensity factor. Numerical examples show the electro-mechanical
effects of various material combinations and layer thicknesses on the stress intensity factor. Interesting results are obtained
in comparison with earlier solutions for interfacially cracked piezoelectric structures.
Received 29 December 2000; accepted for publication 3 May 2001 相似文献
5.
S.-M. Kwon H.-S. Choi K.-Y. Lee 《Archive of Applied Mechanics (Ingenieur Archiv)》2002,72(2-3):160-170
Summary The steady-state of a propagation eccentric crack in a piezoelectric ceramic strip bonded between two elastic materials under
combined anti-plane mechanical shear and in-plane electrical loadings is considered in this paper. The analysis based on the
integral transform approach is conducted on the permeable crack condition. Field intensity factors and energy release rate
are obtained in terms of a Fredholm integral equation of the second kind. It is shown for this geometry that the crack propagation
speed has influence on the dynamic energy release rate. The initial crack branching angle for a PZT-5H piezoceramic structure
is predicted by the maximum energy release rate criterion.
Received 23 January 2001; accepted for publication 18 October 2001 相似文献
6.
Hyung Jip Choi 《Archive of Applied Mechanics (Ingenieur Archiv)》2002,72(4-5):342-362
Summary Plane elasticity solutions are presented for the problem of an oblique crack in two bonded media. The material model under
consideration consists of a homogeneous half-plane with an arbitrarily oriented crack and a nonhomogeneous half-plane. The
Fourier integral transform method is employed in conjunction with the coordinate transformations of field variables in the
basic elasticity equations. Formulation of the crack problem results in having to solve a system of singular integral equations
for arbitrary crack surface tractions. A crack perpendicular to or along the bonded interface between the homogeneous and
nonhomogeneous constituents arises as a limiting case. In the numerical results, the values of mixed-mode stress intensity
factors are provided for various combinations of relevant geometric and material parameters of the bonded media. Subsequently,
the infinitesimal kinks from the tips of a main crack are presumed, with the corresponding local driving forces being evaluated
in terms of the stress intensities of the main crack. The criterion of maximum energy release rate is applied with the aim
of making some conjectures concerning the likelihood of kinking and the probable kink direction based on the approximation
of local homogeneity and brittleness of the crack-tip behavior.
Received 25 September 2001; accepted for publication 13 February 2002 相似文献
7.
X. F. Ding T. Furukawa H. Nakanishi 《Archive of Applied Mechanics (Ingenieur Archiv)》2002,72(2-3):107-118
Summary This paper investigates the stress-focusing effect in an infinitely long cylinder under rotationally asymmetrical instantaneous
thermal loading on the basis of the generalized thermoelastic Lord–Shulman (L-S) and Green–Lindsay (G-L) theories. Combined
forms of the governing equations of both theories are given in a cylindrical coordinate system. The two-dimensional generalized
thermoelastic problems are solved by numerical inversion of Laplace transform. Calculations have been performed to find distributions
of thermal stresses on the basis of the L-S theory. Stress-focusing phenomena under different heating conditions are presented.
The effects of thermomechanical coupling and relaxation time on the stress-focusing phenomena as well as the singularity of
stresses are discussed.
Received 15 November 2000; accepted for publication 15 November 2001 相似文献
8.
Summary Transient dislocation emission from a crack tip under dynamic mode III loading is analyzed. By taking into account the dynamic
interaction between the crack and dislocation, the governing equation for the dislocation motion is derived under the quasi-steady
assumption. The behavior of dislocation emission is explored in detail by solving this equation numerically. A critical initial
speed can be determined, which must be exceeded by dislocations to escape from the crack tip. The dislocation emission process
is found to be completed in such a short time period that the applied load may be approximately treated as constant during
dislocation emission. Based on this fact, an asymptotic criterion for transient dislocation emission is developed, from which
the critical initial speed can be evaluated. In the case that the dislocation is emitted from rest, we recover the quasi-static
criterion of dislocation emission.
Received 22 November 2000; accepted for publication 20 March 2001 相似文献
9.
Dynamic response of a crack in a functionally graded interface of two dissimilar piezoelectric half-planes 总被引:3,自引:0,他引:3
Summary In this paper, the dynamic anti-plane crack problem of two dissimilar homogeneous piezoelectric materials bonded through
a functionally graded interfacial region is considered. Integral transforms are employed to reduce the problem to Cauchy singular
integral equations. Numerical results illustrate the effect of the loading combination parameter λ, material property distribution
and crack configuration on the dynamic stress and electric displacement intensity factors. It is found that the presence of
the dynamic electric field could impede of enhance the crack propagation depending on the time elapsed and the direction of
applied electric impact.
Received 4 December 2001; accepted for publication 9 July 2002
This work is supported by the National Natural Science Foundation of China through Grant No. 10132010. 相似文献
10.
Summary An interface crack problem is investigated under various assumptions on an interface between two elastic materials. The interface
is modeled by an additional third structure (thin elastic wedge of differing elastic properties) matching the bonded materials,
or by introducing special boundary conditions on the crack line ahead. The main emphasis of the paper is placed on a comparison
of the asymptotic expansion of the elastic solutions near the crack tip obtained for the different models. In particular,
the behaviour of the stress singularity exponent and the generalized SIF are discussed. Numerical examples are presented.
Received 16 August 2000; accepted for publication 26 May 2001 相似文献
11.
Summary Green's function approach is adopted for analyzing the deflection and the transient temperature distribution of a plate made
of functionally graded materials (FGMs). The governing equations for the deflection and the transient temperature are formulated
into eigenvalue problems by using the eigenfunction expansion theory. Green's functions for solving the deflection and the
transient temperature are obtained by using the Galerkin method and the laminate theory, respectively. The eigenfunctions
of Green's function for the deflection are approximated in terms of a series of admissible functions that satisfy the homogeneous
boundary conditions of the plate. The eigenfunctions of Green's function for the temperature are determined from the continuity
conditions of the temperature and the heat flux at interfaces.
Received 9 October 2000; accepted for publication 3 April 2001 相似文献
12.
Variation of the stress intensity factor along the front of a 3-D rectangular crack subjected to mixed-mode load 总被引:3,自引:0,他引:3
Summary The singular integral equation method is applied to the calculation of the stress intensity factor at the front of a rectangular
crack subjected to mixed-mode load. The stress field induced by a body force doublet is used as a fundamental solution. The
problem is formulated as a system of integral equations with r
−3-singularities. In solving the integral equations, unknown functions of body-force densities are approximated by the product
of polynomial and fundamental densities. The fundamental densities are chosen to express two-dimensional cracks in an infinite
body for the limiting cases of the aspect ratio of the rectangle. The present method yields rapidly converging numerical results
and satisfies boundary conditions all over the crack boundary. A smooth distribution of the stress intensity factor along
the crack front is presented for various crack shapes and different Poisson's ratio.
Received 5 March 2002; accepted for publication 2 July 2002 相似文献
13.
Summary In a hybrid laminate containing an interfacial crack between piezoelectric and orthotropic layers, the dynamic field intensity
factors and energy release rates are obtained for electro-mechanical impact loading. The analysis is performed within the
framework of linear piezoelectricity. By using integral transform techniques, the problem is reduced to the solution of a
Fredholm integral equation of the second kind, which is obtained from one pair of dual integral equations. Numerical results
for the dynamic stress intensity factor show the influence of the geometry and electric field.
Received 29 June 2001; accepted for publication 3 December 2001 相似文献
14.
Summary The dynamic response of a cracked piezoelectric half-space under anti-plane mechanical and in-plane electric impacting loads
is investigated in the present paper. In the study, the crack is assumed parallel to the free surface of the half-space. Laplace
and Fourier transforms are used to reduce the mixed boundary value problems to Cauchy-type singular integral equations in
the Laplace transform domain, which are solved numerically. Then, a numerical Laplace inversion is performed and the dynamic
stress and electric displacement factors are obtained as functions of time and geometry parameters. The dynamic energy release
rate is derived for piezoelectric materials in terms of the electroelastic intensities and is displayed graphically.
Received 5 January 2000; accepted for publication 28 June 2000 相似文献
15.
Summary This paper deals with the stress concentration problem of an ellipsoidal inclusion of revolution in a semi-infinite body under biaxial tension. The problem is formulated as a system of singular integral equations with Cauchy-type or logarithmic-type singularities, where unknowns are densities of body forces distributed in the r- and z-directions in semi-infinite bodies having the same elastic constants as the ones of the matrix and inclusion. In order to satisfy the boundary conditions along the ellipsoidal boundary, four fundamental density functions proposed in [24, 25] are used. The body-force densities are approximated by a linear combination of fundamental density functions and polynomials. The present method is found to yield rapidly converging numerical results for stress distribution along the boundaries even when the inclusion is very close to the free boundary. The effect of the free surface on the stress concentration factor is discussed with varying the distance from the surface, the shape ratio and the elastic modulus ratio. The present results are compared with the ones of an ellipsoidal cavity in a semi-infinite body.accepted for publication 11 November 2003 相似文献
16.
H. Ferdjani R. Abdelmoula J.-J. Marigo S. El Borgi 《Continuum Mechanics and Thermodynamics》2009,21(1):41-55
The main objective of this work is to prove that, with the Dugdale model, the small size defects, comparatively to the material
characteristic length, are practically without influence on the limit load of structures. For that, we treat the case of a
crack in a semi-infinite plane under anti-plane shear loading. Using integral transforms, the elasticity equations are converted
analytically into a singular integral equation. The singular integral equation is solved numerically using Chebychev polynomials.
Special care is needed to take into account the presence of jump discontinuities in the loading distribution along the crack
lips.
相似文献
17.
The dynamic response of a functionally graded orthotropic strip with an edge crack perpendicular to the boundaries is studied. The material properties are assumed to vary continuously along the thickness direction. Laplace and Fourier transforms are applied to reduce the problem to a singular integral equation. Numerical results are presented to illustrate the influences of parameters such as the nonhomogeneity constant and geometry parameters on the dynamic stress intensity factors (SIFs). 相似文献
18.
E. V. Ermanyuk 《Experiments in fluids》2002,32(2):242-251
This paper presents a study on affine similitude for the force coefficients of an arbitrary body oscillating in a uniformly
stratified fluid. A simple formula is derived that gives a relation between the force coefficients for a body oscillating
in homogeneous and uniformly stratified ideal fluids. In particular, it implies the existence of a universal nondimensional
similitude criterion for a family of affinely similar bodies, namely, the bodies that can be transformed into each other by
vertical dilation of the initial coordinate system. Theoretical results are verified by experiments with a set of spheroids
having different length-to-diameter ratios. The experimental technique for evaluation of the frequency-dependent force coefficients
is based on Fourier analysis of the time-history of damped oscillation tests.
Received: 25 September 2000 / Accepted: 6 July 2001 Published online: 29 November 2001 相似文献
19.
Transient response of an insulating crack between dissimilar piezoelectric layers under mechanical and electrical impacts 总被引:1,自引:0,他引:1
Summary The dynamic response of an interface crack between two dissimilar piezoelectric layers subjected to mechanical and electrical
impacts is investigated under the boundary condition of electrical insulation on the crack surface by using the integral transform
and the Cauchy singular integral equation methods. The dynamic stress intensity factors, the dynamic electrical displacement
intensity factor, and the dynamic energy release rate (DERR) are determined. The numerical calculation of the mode-I plane
problem indicates that the DERR is more liable to be the token of the crack growth when an electrical load is applied. The
dynamic response shows a significant dependence on the loading mode, the material combination parameters as well as the crack
configuration. Under a given loading mode and a specified crack configuration, the DERR of an interface crack between piezoelectric
media may be decreased or increased by adjusting the material combination parameters. It is also found that the intrinsic
mechanical-electrical coupling plays a more significant role in the dynamic fracture response of in-plane problems than that
in anti-plane problems.
Received 4 September 2001; accepted for publication 23 July 2002
The work was supported by the National Natural Science Foundation under Grant Number 19891180, the Fundamental Research Foundation
of Tsinghua University, and the Education Ministry of China. 相似文献
20.
The plane problem of an elliptically reinforced circular hole in an anisotropic plate or laminate 总被引:11,自引:0,他引:11
Summary Within the scope of linear elasticity, the in-plane problem of an anisotropic plate or laminate with a circular hole and
an elliptical hole reinforcement is considered. Arbitrary anisotropic elastic stiffnesses are allowed for the base plate and
the reinforcement material, and for the reinforcement there is no restriction for its elliptical shape and size. The analysis
of the problem is performed by the complex potential method with appropriately chosen series representations inside and outside
the reinforcement region. The derived closed-form solution provides all resultant in-plane stresses and deformations within
and around the hole reinforcement with little computational effort and at high accuracy. The determined solution allows a
proper and effective assessment of hole reinforcements for many technical applications.
Received 26 June 2000; accepted for publication 26 September 2000 相似文献