共查询到20条相似文献,搜索用时 31 毫秒
1.
R. Z. Stasyuk 《Journal of Mathematical Sciences》1996,79(6):1439-1440
We study the elastic equilibrium of a closed infinite circular cylindrical shell with a system of surface cracks of identical
length and depth. We use the method of singular integral equations together with the modeling of solid matter in the plane
of a part-through crack by irregularly distributed “line springs”. We conduct a numerical analysis of the variation of the
relative stress intensity factor at the center of a crack as a function of the parameters of a crack and the number of cracks.
We study cracks located on both the interior and exterior surface of the shell.
Translated fromMatematicheskie Metody i Fiziko-Mekhanicheskie Polya, No. 37, 1994, pp. 63–65. 相似文献
2.
M. M. Nikolishin 《Journal of Mathematical Sciences》1997,86(2):2547-2551
In the context of an analog of the Leonov-Panasyuk-Dagdeil model we consider the problem of limit equilibrium of a nonshallow
transversally isotropic cylindrical shell weakened by a nonthrough surface longitudinal crack. Based on the equations that
take account of the initial stresses, we reduce the problem to a system of two singular integral equations with unknown limits
of integration. We carry out a numerical analysis of the dependence of the opening of the edges of the crack on the load and
the geometric and physico-mechanical parameters of the shell.
Translated fromMatematichni Metodi ta Fiziko-mekhanichni Polya, Vol. 39, No. 1, 1996, pp. 31–36. 相似文献
3.
By using the method of mechanical quadratures we reduce the resolvent integral equation for the problem of an infinite elastic
space with a rectangular crack to a system of linear algebraic equations. We give the results of numerical experiments in
varying the stress intensity factor on one side of the crack in the case of tension in the direction perpendicular to the
plane of the crack.
One figure. Bibliography: 5 titles.
Translated fromTeoreticheskaya i Prikladnaya Mekhanika, No. 28, 1998, pp. 24–28. 相似文献
4.
A. C. Orifici R. S. Thomson R. Degenhardt C. Bisagni J. Bayandor 《Mechanics of Composite Materials》2007,43(1):9-28
Analysing the collapse of skin-stiffened structures requires capturing the critical phenomenon of skin-stiffener separation,
which can be considered analogous to interlaminar cracking. This paper presents the development of a numerical approach for
simulating the propagation of interlaminar cracks in composite structures. A degradation methodology was introduced in MSC.Marc,
which involved the modelling of a structure with shell layers connected by user-defined multiple-point constraints (MPCs).
User subroutines were written that employ the virtual crack closure technique (VCCT) to determine the onset of crack growth
and modify the properties of the user-defined MPCs to simulate crack propagation. Methodologies for the release of failing
MPCs are presented and are discussed with reference to the VCCT assumption of self-similar crack growth. The numerical results
obtained by using the release methodologies are then compared with experimental data for a double-cantilever beam specimen.
Based on this comparison, recommendations for the future development of the degradation model are made, especially with reference
to developing an approach for the collapse analysis of fuselage-representative structures.
Russian translation published in Mekhanika Kompozitnykh Materialov, Vol. 43, No. 1, pp. 15–42, January–February, 2007. 相似文献
5.
Y. I. Kunets V. V. Matus V. V. Mykhas’kiv A. Boström Ch. Zhang 《Mechanics of Composite Materials》2008,44(2):165-172
The problem of interaction of a plane time-harmonic SH-wave with an elastic fiber of quasi-square or quasi-triangular cross
section, when an interface crack is present between an infinite elastic matrix and the fiber, is considered. The modified
null-field method taking into account the asymptotic behavior of the solution at crack tips is exploited for obtaining numerical
results. The effects of fiber shape, fiber/matrix material combination, debonding (crack size), and direction of wave incidence
on the scattering amplitude in the far zone are analyzed.
Russian translation published in Mekhanika Kompozitnykh Materialov, Vol. 44, No. 2, pp. 245–254, March–April, 2008. 相似文献
6.
We consider the perturbed deformed state of a thin shallow isotropic shell of nonnegative Gaussian curvature under the action
of an abruptly applied concentrated normal force. Using the integral Fourier transform method with respect to the geometric
coordinates and the Laplace transform with respect to time we obtain a solution of this problem in the form of double series
in generalized Fresnel sine and cosine integrals. We give numerical results for the initial reaction of the shell at the point
of application of the load. We give a comparison with known results. Two figures. Bibliography: 4 titles.
Translated fromTeoreticheskaya i Prikladnaya Mekhanika, No. 22, pp. 58–63, 1991. 相似文献
7.
We study the interaction of a magnetoelastic shear wave with a curvilinear tunnel crack in an ideally conducting diamagnetic
(resp. paramagnetic) one-sided (resp. two-sided) layer in the presence of an external static magnetic field. The bases of
the one-sided layer are free of mechanical load, and the rim of the face is clamped or free. The corresponding linearized
boundary-value problem of magnetoelasticity is reduced to a singular integrodifferential equation with subsequent implementation
on a computer. We give numerical results that characterize the influence of the size of the preliminary magnetic field, the
frequencies of the load, the curvature, and the orientation of the crack on the stress intensity factor.
Translated fromTeoreticheskaya i Prikladnaya Mekhanika, No. 23, 1992, pp. 96–102. 相似文献
8.
On the basis of numerical computations we analyze the echo-signals from a steel spherical shell located near the bottom of
water under the action of a quasimonochromatic pulse. We study the effect of the distance between the sphere and the bottom
on the echo-pulse.
Translated fromMatematichni Metodi i Fiziko-mekhanichni Polya, Vol. 40, No. 1, pp. 79–84. 相似文献
9.
A. O. Kamins’kyi L. A. Kipnis M. V. Dudyk Yu. V. Dikhtyarenko 《Journal of Mathematical Sciences》2010,167(1):128-139
We perform calculation of the initial prefracture zone at the tip of a mode I crack that reaches a nonsmooth interface of
two dissimilar elastic media at its corner point by the Wiener–Hopf method. The zone is modeled by a line of normal displacement
fracture on a crack continuation. Expressions for the length of the prefracture zone and the potential energy accumulated
in it are obtained. Their numerical values are compared with the corresponding values for the prefracture zone in a bonding
material on the interface of the media, on the basis of which we draw a conclusion on the possible direction of development
of the zone. 相似文献
10.
Using Lekhnitskii's method of complex potentials we study the stress state of an anisotropic plate with two arbitrary elliptic
holes. We consider the cases when one or both of the holes become narrow slit-cracks, when the cracks extend to the edge of
the hole, and when two cracks intersect or form a broken two-link crack. We give the results of numerical studies.
Translated fromTeoreticheskaya i Prikladnaya Mekhanika, No. 24, 1993, pp. 33–43. 相似文献
11.
V. V. Porokhovs’kyi 《Journal of Mathematical Sciences》2009,160(4):443-452
We have proposed a procedure for investigating the stressed state of a thin-walled round cylindrical shell with a cut along
its generatrix, which is placed into an elastic space. A longitudinal elastic wave is incident on the shell. The procedure
is based on the use of the Rayleigh expansion in partial waves. We have obtained relations for determining the displacement
jumps and angle of rotation at the lips of the shell cut, the radial component of the displacement vector and the normal force
in the cylindrical shell, as well as the stresses and displacements in the elastic medium.
Translated from Matematychni Metody ta Fizyko-Mekhanichni Polya, Vol. 51, No. 1, pp. 131–137, January–March, 2008. 相似文献
12.
An analysis of the crack closure and fatigue crack growth rate have been carried out for an infinitely long poled piezoelectric
ceramic strip weakened by a straight hair line internal crack. The ceramic under consideration is assumed to be mechanically
more brittle. The crack faces are perpendicular to the poled direction of the strip. The crack faces open in Mode-I deformation
on account of in-plane tension applied to the edges of the strip together with either an in-plane electric displacement prescribed
on edges of the strip or a uniform constant electric field prescribed on its edges. As a result, a yield zone is formed ahead
of each tip of the crack. The yield zones developed are then arrested by applying a normal, cohesive, linearly varying yield
point-stress to their rims. For each case, the Fourier transform method is used to find a solution. The resulting integral
equations are solved numerically. Expressions are derived for the crack opening displacement and the crack growth rate. The
variations in these quantities are plotted in relation to the affecting parameters, viz., the strip thickness, the yield zone
length, the electric displacement, and material constants. A case study is presented graphically for PZT-4, PZT-5H, and BaTiO3 ceramics.
Russian translation published in Mekhanika Kompozitnykh Materialov, Vol. 44, No. 5, pp. 647–664, September–October, 2008. 相似文献
13.
On the basis of the Timoshenko kinematic hypothesis for shells we give a formulation of the problem of studying the stress-strain
state of orthotropic plates and shells weakened by a combined stress concentrator (a hole with two symmetric cracks extending
to its edge).
We propose a method of solving such problems on the basis of the finite-element method. To simulate the singularity of the
stresses and displacements in a neighborhood of the tip of a crack we apply special finite elements with degenerate faces
and nodes displaced by 1/4 the length of an edge. The stress intensity factors are found in terms of the displacements of
the nodes of such elements.
We give the results of computation of the concentration coefficients and the stress intensity factors for spherical and cylindrical
shells loaded by internal pressure and for a cylindrical shell and a plate under the action of a distending load with various
concentrators: a circular hole, an isolated crack, and a combined concentrator.
Translated fromTeoreticheskaya i Prikladnaya Mekhanika, No. 23, 1992, pp. 48–54. 相似文献
14.
We present a method for rational application of the deformation properties of a shell system with an elastic filler: design
of a shell with variable thickness while preserving the load-bearing ability of the system as a whole. For the equi-strength
shell thereby obtained we state and solve the mixed contact problem taking account of dry friction with nonmonotone loading,
making it possible to estimate the structural hysteresis in the system.
Translated fromMatematicheskie Metody i Fiziko-Mekhanicheskie Polya, No. 37, 1994, pp. 86–91. 相似文献
15.
A. A. Alekseichuk Yu. A. Kostandov L. Ya. Lokshina 《Journal of Mathematical Sciences》1996,82(3):3444-3446
We obtain the values of the stress intensity factor at the end of a stationary crack under dynamic load using a numerical
method. We compare the results with the existing experimental data. We establish that it is possible to apply the proposed
method to compute stationary cracks under dynamic load.
Translated fromDinamicheskie Sistemy, No. 13, 1994, pp. 61–65. 相似文献
16.
We study the problem for a spherical shell weakened by thermally insulated slits. Using the two-dimensional Fourier transform
and the elements of the theory of distributions, we obtain the resolvent systems of singular integral equations. We carry
out numerical studies of the influence of the geometric parameters of the shell and the slits on the values of the coefficients
of intensity of the forces and moments. Three figures. Bibliography: 5 titles.
Translated fromTeoreticheskaya i Prikladnaya Mekhanika, No. 26, 1996, pp. 75–81. 相似文献
17.
On the basis of general representations of the generalized complex potentials for a multiconnected half-plane, which the authors
have obtained, we solve problems for a multiconnected half-plane with holes and cracks when external forces or dies act on
the boundary of the half-plane. Using conformal mapping for an ellipse and the method of least squares, we reduce these problems
to solving a system of linear algebraic equations. For different anisotropic materials we give the results of studies of the
stress distributions and the variation of the stress intensity factors for a half-plane with a crack in the case of tension
at infinity, internal pressure on the edges of the crack, and the action of normal forces on the rectilinear boundary. Two
figures, 2 tables. Bibliography: 2 titles.
Translated fromTeoreticheskaya i Prikladnaya Mekhanika, No. 27, 1997, pp. 63–72. 相似文献
18.
Initiation of Cracks in Griffith’s Theory: An Argument of Continuity in Favor of Global Minimization 总被引:1,自引:0,他引:1
Jean-Jacques Marigo 《Journal of Nonlinear Science》2010,20(6):831-868
The initiation of a crack in a sound body is a real issue in the setting of Griffith’s theory of brittle fracture. If one
uses the concept of critical energy release rate (Griffith’s criterion), it is in general impossible to initiate a crack.
On the other hand, if we replace it by a least energy principle (Francfort–Marigo’s criterion), it becomes possible to predict
the onset of cracking in any circumstance. However this latter criterion can appear too strong. We propose here to reinforce
its interest by an argument of continuity. Specifically, we consider the issue of the initiation of a crack at a notch whose
angle ω is considered as a parameter. The result predicted by the Griffith criterion is not continuous with respect to ω, since no initiation occurs when ω>0 while a crack initiates when ω=0. In contrast, the Francfort–Marigo’s criterion delivers a response which is continuous with respect to ω, even though the onset of cracking is necessarily brutal when ω>0. The theoretical analysis is illustrated by numerical computations. 相似文献
19.
E. N. Dovbnya 《Journal of Mathematical Sciences》1998,90(1):1903-1905
We study the stress-strain state of an orthotropic shell with a circular hole. The regularities of the straiin distribution
as a function of the anisotropy parameters in a spherical shell are exhibited. One table, 1 figure. Bibliography: 3 titles.
Translated fromTeoreticheskaya i Prikladnaya Mekhanika, No. 27, 1997, pp. 154–158. 相似文献
20.
Using an analog of the δ
c
-model, we have obtained a solution of the problem of the stress-strain state of an elastoplastic orthotropic shell, having
an arbitrary curvature, with a surface crack. Here, additional constraints on the elastic parameters of the material are not
imposed. Furthermore, we have studied the dependence of the length of the plastic zone and surface-crack opening on the level
of load, the shell and crack geometrical parameters, and the mechanical properties of the material. 相似文献