共查询到20条相似文献,搜索用时 15 毫秒
1.
林拜松 《应用数学和力学(英文版)》1993,14(7):643-648
On condition that any perfectly plastic stress component at a crack tip is nothingbut the function ofθ.by making use of equilibrium equations,anisotropic plastic stress-strain-rate relations,compatibility equations and Hill anisotropic plastic yieldcondition,in the present paper,we derive the generally analytical expressions of theanisotropic plastic stress field at a mixed-mode crack tip under plane and anti-planestrain.Applying these generally analytical expressions to the mixed-mode cracks,wecan obtain the analytical expressions of anisotropic plastic stress fields at the tips ofmixed-modeⅠ-Ⅲ,Ⅱ-ⅢandⅠ-Ⅱ-Ⅲcracks. 相似文献
2.
袁镒吾 《应用数学和力学(英文版)》1987,8(11):1069-1077
In [1], under the condition that all the perfectly plastic stress components at a crack tip are functions of ϕ only, making
use of equilibrium equations, stress-strain rate relations, compatibility equations and yield condition. Lin derived the general
analytical expressions of the perfectly plastic stress field at a mixed-mode crack tip under plane and anti-plane strain.
But in [1] there were several restrictions on the proportionality factor γ in the stress-strain rate relations, such as supposing
that γ is independent of ϕ and supposing that γ=c or cr−1. In this paper, we abolish these restrictions. The cases in [1], γ=crd (n=0 or-1) are the special cases of this paper. 相似文献
3.
A mixed-mode (I + II) crack model with a plastic strip on its continuation under plane strain is proposed. The stress components
within the strip are determined from the yield conditions, stress limitation, and relationship between the normal stress components
defined via the principal stress state. The crack parameters are analyzed for the Mises yield condition. In the quasibrittle
case, the governing system of equations includes stress intensity factors K
I, K
II, and T-stresses 相似文献
4.
《International Journal of Solids and Structures》2005,42(18-19):5208-5223
On the basis of the two-dimensional theory of anisotropic thermoelasticity, a solution is given for the thermal stress intensity factors due to the obstruction of a uniform heat flux by an insulated line crack in a generally anisotropic half plane. The crack is replaced by continuous distributions of sources of temperature discontinuity and dislocations. First, the particular thermoelastic dislocation solutions for the half plane are obtained; then the corresponding isothermal solutions are superposed to satisfy the traction-free conditions on the crack surfaces. The dislocation solutions are applied to calculate the thermal stress intensity factors, which are validated by the exact solutions. The effects of the uniform heat flux, the ply angle and the crack length are investigated. 相似文献
5.
Inverse analysis is widely applied to the identification of material properties or model parameters. In order to improve the computational efficiency of the inverse method based on the genetic algorithm, an interpolation scheme upon the response surface constructed by the finite element simulation has been adopted in this paper. Meanwhile, a gradual homogenization treatment scheme has also been presented to improve the convergence of the inverse method based on the Kalman filter algorithm. Both methods are proven effective in dealing with the single-objective inverse problem. However, literature studies show that the adoption of multiple types of experimental information is useful to improve the accuracy of inverse analysis. In this case, it turns into a multiple-objective inverse problem. Our practice proved that the above-mentioned two methods might not yield a proper result if the sensitivity issue of different types of information is not considered. Therefore, another multi-objective inverse method, in combination of the above two optimization algorithms and a weight-estimating scheme that can consider such sensitivity, has been further presented. Finally, by using a mixed-mode crack propagation simulation and two types of experimental information (loading-displacement response curve and crack path profile), the parameters of the cohesive zone model were inversely identified and its simulation results are in good agreement with the experiment. 相似文献
6.
7.
Y.C. Gao 《Theoretical and Applied Fracture Mechanics》1997,27(3):203-212
The pseudo plane stress field for a mode I crack growth is analyzed for both perfectly plastic and power law hardening plastic materials. When finite strain is taken into account, it is found that for perfectly plastic materials, the plastic domain is a narrow strip ahead of the crack tip. For power law hardening plastic material, the plastic domain contains a strip and a region ahead of the strip. The fracture criterion is discussed. The energy dissipated in the plastic strip is found to be proportional to the square of the thickness. Singular solutions to the field are ruled out by analysis. 相似文献
8.
THE EXACT SOLUTIONS OF ELASTIC-PLASTIC CRACK LINE FIELD FOR MODE ⅡPLANE STRESS CRACK 总被引:1,自引:2,他引:1
THEEXACTSOLUTIONSOFELASTIC-PLASTICCRACKLINEFIELDFORMODEIIPLANESTRESSCRACKYiZhijian(易志坚)WangShijie(王士杰)WangXiangjian(王向坚)(Rece... 相似文献
9.
V. S. Kirilyuk 《International Applied Mechanics》2008,44(3):320-330
The paper addresses a thermoelectroelastic problem for a piezoelectric body with an arbitrarily shaped plane crack in a plane
perpendicular to the polarization axis under a symmetric thermal load. A relationship between the intensity factors for stress
(SIF) and electric displacement (EDIF) in an infinite piezoceramic body with a crack under a thermal load and the SIF for
a purely elastic body with a crack of the same shape under a mechanical load is established. This makes it possible to find
the SIF and EDIF for an electroelastic material from the elastic solution without the need to solve specific problems of thermoelasticity.
The SIF and EDIF for a piezoceramic body with an elliptic crack and linear distribution of temperature over the crack surface
are found as an example
__________
Translated from Prikladnaya Mekhanika, Vol. 44, No. 3, pp. 96–108, March 2008. 相似文献
10.
Liu Cheng 《Acta Mechanica Sinica》1989,5(3):244-252
In this paper, the dynamic propagation problem of a mixed-mode crack was studied by means of the experimental method of caustics.
The initial curve and caustic equations were derived under the mixed-mode dynamic condition. A multi-point measurement method
for determining the dynamic stress intensity factors,K
I
d
, andK
II
d
, and the position of the crack tip was developed. Several other methods were adopted to check this method, and showed that
it has a good precision. Finally, the dynamic propagating process of a mixed-mode crack in the three-point bending beam specimen
was investigated with our method. 相似文献
11.
An integral formulation for computing the nonsingular stresses (NSS) in a cracked body under mixed-mode static and dynamic loads is presented. The reciprocity theorems are applied to find the integral formula. The auxiliary fields are selected to eliminate the singular terms in the asymptotic expansion of the stresses near the crack tip. For elastodynamic crack problems, the integral representation of the NSS is presented in both the time and Laplace transform domain. Required variables along the integration path and region enclosed by the integration contour are obtained from the boundary element analysis. Influence of the NSS on predicting the crack growth direction is investigated for cracks under mixed-mode load conditions. 相似文献
12.
V. S. Kirilyuk 《International Applied Mechanics》2006,42(2):152-161
The static equilibrium of an electroelastic transversely isotropic space with a plane crack under antisymmetric mechanical
loads is studied. The crack is located in the plane of isotropy. Relationships are established between the stress intensity
factors (SIFs) for an infinite piezoceramic body and the SIFs for a purely elastic body with a crack of the same form under
the same loads. This makes it possible to find the SIFs for an electroelastic body without the need to solve specific electroelasitc
problems. As an example, the SIFs are determined for a piezoelastic body with penny-shaped and elliptic cracks under shear
__________
Translated from Prikladnaya Mekhanika, Vol. 42, No. 2, pp. 32–42, February 2006. 相似文献
13.
V. A. Saraikin 《Journal of Applied Mechanics and Technical Physics》1999,40(5):903-907
Equations are derived for stress concentration near a crack of closed contour lying in a plane. A system of one-dimensional
integral equations for the concentration factor is obtained. The right sides of the equations contain the initial approximation—a
solution of the problem of a circular crack whose sides are acted upon by nonaxisymmetric loading.
Mining Institute, Siberian Division, Russian Academy of Sciences, Novosibirsk 630091. Translated from Prikladnaya Mekhanika
i Tekhnicheskaya Fizika, Vol. 40, No. 5, pp. 143–148, September–October, 1999. 相似文献
14.
V. S. Kirilyuk 《International Applied Mechanics》2008,44(7):757-768
The paper establishes a relationship between the solutions for cracks located in the isotropy plane of a transversely isotropic
piezoceramic medium and opened (without friction) by rigid inclusions and the solutions for cracks in a purely elastic medium.
This makes it possible to calculate the stress intensity factor (SIF) for cracks in an electroelastic medium from the SIF
for an elastic isotropic material, without the need to solve the electroelastic problem. The use of the approach is exemplified
by a penny-shaped crack opened by either a disk-shaped rigid inclusion of constant thickness or a rigid oblate spheroidal
inclusion in an electroelastic medium
__________
Translated from Prikladnaya Mekhanika, Vol. 44, No. 7, pp. 47–60, July 2008. 相似文献
15.
Tao Zhou Xinhua Yang Chuanyao Chen 《International Journal of Solids and Structures》2009,46(9):1975-1980
The quasicontinuum (QC) method is employed to simulate a nickel single crystal nano-plate with a mixed-mode crack. Atomic stresses near the crack tip are fitted according to the elastoplastic fracture mechanics equations. It is found that the atomic stress fields neighboring the crack tip are also singular and controlled by the atomic stress intensity factors. And then the critical energy release rates for brittle and ductile fracture are computed and compared in order to predict crack propagation or dislocation emission. Four possible slip directions at the crack tip are pointed out. Finally, the slip direction around the crack tip is determined by the shear stress and it is well consistent with the atomic pictures from the QC simulation. 相似文献
16.
V. S. Kirilyuk 《International Applied Mechanics》2008,44(10):1106-1118
The static equilibrium of a transversely isotropic magnetoelectroelastic body with a plane crack of arbitrary shape in the
isotropy plane under antisymmetric mechanical loading is studied. The relationships between the stress intensity factors (SIFs)
for an infinite magnetoelectroelastic body and the SIFs for a purely elastic body with the same crack and under the same antisymmetric
loading are established. This enables the SIFs for a magnetoelectroelastic body to be found directly from the analogous problem
of elasticity. As an example of using this result, the SIFs for penny-shaped, elliptic, and parabolic cracks in a magnetoelectroelastic
body under antisymmetric mechanical loading are found
Translated from Prikladnaya Mekhanika, Vol. 44, No. 10, pp. 37–51, October 2008. 相似文献
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19.
A finite element study of stable crack growth in ceramics that can undergo a stress-induced martensitic phase transformation is performed under plane stress and small scale transforming conditions. The finite element method is based on the continuum model developed by Budiansky et al. (Int. J. Solids Structures 19, 1983). To guarantee the subcritical transformation behavior without loss of ellipticity of the governing equations, the possibility of strain localization is first re-examined. It is found that the plane stress conditions greatly favor transformation instability in that supercritical transformation occurs when the bulk modulus ¯B during transformation is below –G/3, instead of –4G/3 for three-dimensional or plane strain cases, whereG is the shear modulus. Next, transient crack extension under continuously increasing tensile load is simulated by a node release technique. Transformation zones and crack growth resistance curves are obtained. 相似文献
20.
Y.C. Gao 《Theoretical and Applied Fracture Mechanics》1997,27(3):193-202
The near tip field of mode II crack that grows in thin bodies with power hardening or perfectly plastic behavior is analyzed. It is shown that for power hardening behavior, the pseudo plane stress field possesses the logarithm singularity, i.e. σ (ln r)2/(n−1), (ln r)2n/(n − 1), where r is the distance from the crack tip, n the hardening exponent is σn. When n → ∞ the solution reduced to that for the perfectly plastic case. 相似文献