共查询到15条相似文献,搜索用时 15 毫秒
1.
The problem of a radial crack in cross-ply laminates under uniaxial tension is investigated in this paper. The normalized
stress intensity factors are obtained by the modified mapping collocation method which is based on analytic complex function
theory of complex variables. The present results for an isotropic infinite plate show good agreement with existing solutions.
In the range of small crack length, the stress intensity factor for a radial crack in cross-ply laminates under uniaxial tension
becomes larger as the percentage of 0° plies increases. However in the range of large crack length, it is insensitive to the
percentage of 0° plies. 相似文献
2.
Hyeong-Yeon Lee Seok-Hoon Kim Jae-Han Lee Byung-Ho Kim 《Journal of Mechanical Science and Technology》2006,20(12):2136-2146
A study on a creep-fatigue crack growth behavior has been carried out for a cylindrical structure with weldments by using
a structural test and an evaluation according to the assessment procedures. The creep-fatigue crack growth behavior following
the creep-fatigue crack initiation has been assessed by using the French A16 procedure and the conservatism for the present
structural test has been examined. The structural specimen is a welded cylindrical shell made of 316 L stainless steel (SS)
for one half of the cylinder and 304 SS for the other half. In the creep-fatigue test, the hold time under a tensile load
which produces the primary nominal stress of 45 MPa was one hour at 600°C and creep-fatigue loads of 600 cycles were applied.
The evaluation results for the creep-fatigue crack propagation were compared with those of the observed images from the structural
test. The assessment results for the creep-fatigue crack behavior according to the French A16 procedure showed that the A16
is overly conservative for the creep-fatigue crack propagation in the present case with a short hold time of one hour. 相似文献
3.
Hyeon Gyu Beom Kyoung Moon Jeong Eun Do Jeong 《Journal of Mechanical Science and Technology》2002,16(8):1117-1126
A conducting crack in an electrostrictive ceramic under combined electric and mechanical loading is investigated. Analysis
based on linear dielectric model predicts that the surfaces of the crack are not open completely but they are contact near
the crack tip. The complete solution for the crack with a contact zone in a linear electrostrictive ceramic under combined
electric and mechanical loading is obtained by using the complex variable formula. The asymptotic problems for a semi-infinite
crack with a partial opening zone as well as for a fully open semi-infinite crack in a nonlinear electrostrictive ceramic
are analyzed in order to investigate the effect of the electrical nonlinearity on the stress intensity factor under small
scale nonlinear conditions. Particular attention is devoted to a finite crack in the nonlinear electrostrictive ceramic subjected
to combined electric and mechanical loading. The stress intensity factor for the finite crack under small scale nonlinear
conditions is obtained from the asymptotic analysis. 相似文献
4.
The effects of cavities on maximum equivalent stresses of buried pipelines are investigated in terms of two factors such as
size and location of the underground cavities by using a finite element code. It has been found that the cavities affect maximum
equivalent stresses of buried pipeline significantly in case that the diameters of cavities are larger than that of the pipeline.
The variation of the stress intensity factors for a crack existing on the buried pipeline nearby cavities is also studied.
The mode II stress intensity factor, KII, for a tilt crack located at the top portion of a buried pipeline is found to be influenced significantly regardless of the
location of the underground cavities. 相似文献
5.
The problem of a crack approaching a circular hole in cross-ply laminates under uniaxial and biaxial loading is investigated
in this paper. The effects of material orthotropy, geometry [R/d and a/d], and loading conditions on crack tip singularity
are investigated. The stress intensity factors are obtained by the modified mapping collocation method. The present results
for an isotropic infinite plate show good agreement with existing solutions. The results for cross-ply laminates show that
the stress intensity factors strongly depend on material orthotropy, geometry, and loading condition. The stress intensity
factors for cross-ply laminates exist between those for θ=0° and those for θ=90° in the whole range of crack length and decrease
as the percentage of 0° plies increases. In the range of small crack length the stress intensity factors for biaxial tension
are higher than those for uniaxial tension. In the range of large crack length the stress intensity factors for uniaxial tension
are higher than those for biaxial tension. 相似文献
6.
A cracked plate with a patch bonded on one side was treated with a crack-bridging model using weight function : assuming continuous
distribution of springs acting between th crack surfaces, the stress intensity factor of the patched crack was numerically
obtained. Especially in the case of a patched crack subjected to residual non-uniform stress, the stress intensity factor
was easily with the corresponding approximate weight function. This paper presented the stress intensity factors for a crack
partially patched within a finite plate or a patched crack initiated from a notch. 相似文献
7.
8.
In this paper, we examine the singular stresses and electric fields in a functionally graded piezoelectric ceramic strip containing
an eccentric crack off the center line under anti-plane shear loading with the theory of linear piezoelectricity. It is assumed
that the properties of the functionally graded piezoelectric ceramic strip vary continuously along the thickness. Fourier
transforms are used to reduce the problem to the solution of two pairs of dual integral equations, which are then expressed
to a Fredholm integral equation of the second kind. Numerical values on the stress intensity factor and the energy release
rate are obtained. 相似文献
9.
The singular stress field and stress intensity factors of a crack terminating at a bimaterial interface 总被引:1,自引:0,他引:1
For the fracture evaluation of inclined cracks terminating at the dissimilar material interface, not only the singularities, but also the detailed stress field and its stress intensity factors are necessary. However, though there are many researches reported on the singularity analysis, the stress field and its stress intensity factors are still not clear. This paper has deduced theoretically the singular stress and displacement fields near the tip of a crack terminating at the interface between bonded dissimilar materials, for both cases of real and oscillatory singularities. From the deduced singular stress field, the stress intensity factors are defined for such a crack, and the corresponding numerical extrapolation methods are also proposed. Through the numerical examinations, it is found that the theoretical stress distributions agree well with the numerical results obtained by the finite element method. Moreover, the proposed extrapolation method shows a good linearity, thus it can be used as an efficient way to determine the characteristics of the stress and displacement fields near the tip of a crack terminating at interface. 相似文献
10.
The dynamic response of an eccentric Griffith crack in functionally graded piezoelectric ceramic strip under anti-plane shear
impact loading is analysed using integral transform method. Laplace transform and Fourier transform are used to reduce the
problem to two pairs of dual integral equations, which are then expressed to Fredholm integral equations of the second kind.
We assume that the properties of the functionally graded piezoelectric material vary continuously along the thickness. The
impermeable crack boundary condition is adopted. Numerical values on the dynamic stress intensity factors are presented for
the functionally graded piezoelectric material to show the dependence of the gradient of material properties and electric
loadings. 相似文献
11.
The use of fracture mechanics has traditionally concentrated on crack growth under an opening mechanism. However, many service
failures occur from cracks subjected to mixed-mode loading. Hence, it is necessary to evaluate the fatigue behavior under
mixed-mode loading. Under mixed-mode loading, not only the fatigue crack propagation rate is of importance, but also the crack
propagation direction. In modified range 0.3≤a/W≤0.5, the stress intensity factors (SIFs) of mode I and mode II for the compact
tension shear (CTS) specimen were calculated by using elastic finite element analysis. The propagation behavior of the fatigue
cracks of cold rolled stainless steels (STS304) under mixed-mode conditions was evaluated by using KI and KII(SIFs of mode I and mode II). The maximum tangential stress (MTS) criterion and stress intensity factor were applied to predict
the crack propagation direction and the propagation behavior of fatigue cracks. 相似文献
12.
A general solution to the problem of a crack lying in a viscoelastic layer sandwiched between two different media under an anti-plane concentrated load is presented. The fundamental elastic solution is obtained as a rapidly convergent series in terms of complex potentials via successive iterations of Möbius’ transformation in order to satisfy continuity conditions on two different interfaces. Based on the correspondence principle, the Laplace-transformed viscoelastic solution is then directly determined from the corresponding elastic solution. Therefore, the time-dependent mode-III stress intensity factor (SIF) of the crack tip can be solved numerically in a straightforward manner. Furthermore, the viscoelastic moduli of polyurethane at various temperatures are regressed from a uni-axial test with a constant load while a standard solid model is applied to formulate the viscoelastic constitutive equation. Finally, the effects of working temperature, boundary conditions and the geometric relation on the SIF are also discussed. 相似文献
13.
Ouk Sub Lee Min Ku Han Sung Kyung Hong 《Journal of Mechanical Science and Technology》1989,3(2):159-163
This report investigates the effect of the first few higher-order, non-singular stress terms and the coefficient of optical
anisotropy on the shapes of the initial curves and the caustics in birefringent plates under Mode I and Mode II static loading
conditions. For Mode I and Mode II loading conditions, Williams stress function is employed to generate various theoretical
initial curves and caustics. Some experimentally obtained double caustics are compared to the theoretically generated double
caustics. The agreement is found to be good as far as the shapes of caustics are concerned although it is not easy, if not
impossible, to distinguish the effect of each higher-order terms. 相似文献
14.
The anti-plane shear problem of bonded elastic materials containing a crack at an arbitrary angle to the graded interfacial
zone is investigated in this paper. The interfacial zone is modeled as a nonhomogeneous interlayer of finite thickness with
the continuously varying shear modulus between the two dissimilar, homogeneous half-planes. Formulation of the crack problem
is based upon the use of the Fourier integral transform method and the coordinate transformations of basic field variables.
The resulting Cauchy-type singular integral equation is solved numerically to provide the values of modeIII stress intensity factors. A comprehensive parametric study is then presented of the influence of crack obliquity on the stress
intensity factors for different crack size and locations and for different material combinations, in conjunction with the
material nonhomogeneity within the graded interfacial zone. 相似文献
15.
Toshikazu Fujino Katsumi Iwamoto Kentaro Tanaka Masayuki Shima 《Tribology International》2007,40(10-12):1638
In recent years, the techniques improving sliding performances have progressed by using coated films possessing superior tribological properties, to reduce the failures of the mechanical elements. Those techniques are often used under severe conditions such as elastohydrodynamic lubrication (EHL). In this paper, numerical three-dimensional analysis of the maximum shear stress applied into the coated film and substrate under a single EHL operating condition was performed with a range of coated film thickness and elastic properties. The strength of coated film as one of those techniques was evaluated numerically, resulting in an optimum design of coated film. As a result, coated films with a larger value of thickness and a smaller modulus of elasticity than that of substrate are preferable. 相似文献