• Journal of the Korean Society for Precision Engineering
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• v.16 no.10
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• pp.152-163
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• 1999

The problem of eigenvalue and eigenvector for v-notched cracks in pseudo-isotropic and anisotropic dissimilar materials was obtained to discuss stress singularities from traction free boundary and perfect bonded interface conditions assuming like the form of complex stress function for v-notched cracks in an isotropic material. Eigenvalues were solved by a commercial numerical program, MATHEMATICA. The relation between wedged angle and material property for eigenvalue, ${\lambda}$ indicating stress singularities of v-notched cracks in pseudo-isotropic and anisotropic dissimilar materials was examined.

• Structural Engineering and Mechanics
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• v.7 no.2
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• pp.147-157
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• 1999

An analytical methodology for solving antiplane problem of anisotropic materials is proposed and discussed in detail in this study. The material considered in this study possesses a symmetry plane at z=0. The relationship between the problems of anisotropic materials and the corresponding isotropic problems are established by Ma (1996) on the basis of the general solutions for the shear stresses and displacement in both the polar and Cartesian coordinate systems. This implies that any solution of an anisotropic problem can be obtained by solving a corresponding isotropic problem. In this study some examples and numerical results are presented as an explanation of how the complicated anisotropic problem could be solved by the associated simpler isotropic problem.

• Journal of the Korean Society for Precision Engineering
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• v.18 no.12
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• pp.88-94
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• 2001

The V-notched crack problem in dissimilar materials can be formulated as an eigenvalue problem. The RWCIM(Reciprocal Work Contour Integral Method) is applied to the determination of the eigenvector coefficients associated with eigenvalues for V-notched cracks in pseudo-isotropic and anisotropic dissimilar materials. The RWCIM algorithm is programed by the commercial numerical program, MATHEMATICA. The numerical results obtained are shown that the RWCIM is a useful method for determining the eigenvector coefficients of V-notched cracks in pseudo-isotropic and anisotropic dissimilar materials.

• Transactions of the Korean Society of Mechanical Engineers
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• v.17 no.2
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• pp.359-370
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• 1993

Up to now, most studies are on interface crack problems in isotropic-isotropic dissimilar materials, but it seems to be not so much on anisotropic dissimlar materials. In this study, the stress intensity factors for an interface crack in anisotropic dissimilar materials are analysed using author's proposed extrapolation method by BEM and we have done a parametric study about material properties or shapes of crack affecting to the stress intensity factors. However, as there are not other's comparable numerical results on these anisotropic dissimilar materials to the best of author's knowledge, the reliability of the present results was proved by following two methods. The first is considering the asymptotic characteristic about stress intensity factors for an interface crack in anisotropic materials when the ansiotropic material approachs to the isotropic material. The second is considering the discontinuity of stress intensity factors between of a crack in an identical homogeneous anisotropic material and an interface crack in anisotropic dissimilar materials.

• International Journal of Precision Engineering and Manufacturing
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• v.3 no.2
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• pp.22-32
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• 2002

V-notched crack problems can be formulated as eigenvalue problems. The problem ova v-notched crack in anisotropic and/or pseudo-isotropic dissimilar materials was formulated as an eigenvalue problem to discuss stress singularities. The eigenvalue problem was served by the commercial numerical program; MATHEMATICA. The specific data of eigenvalues possessing the stress singularity were obtained. Stress singularities fur v-notched cracks in anisotropic and/or pseudo-isotropic dissimilar materials were discussed according to the relation between wedge angle and material property. It was shown that there are three cases of eigenvalues possessing the stress singularity; one real, two real and one complex.

• Journal of the Optical Society of Korea
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• v.17 no.1
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• pp.33-37
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• 2013

In this study a new design concept of the Fabry-Perot filter, constructed with an anisotropic space layer and a couple of isotropic mirrors, was proposed based on the Maxwell equations and the characteristic matrix method. The single- and double-cavity Fabry-Perot filters were designed, and their optical properties were investigated with a developed software package. In addition, the dependence of the transmittance and phase shift for two orthogonal polarization states on the column angle of the anisotropic space layer and the incidence angle were discussed. We demonstrated that the polarization state of electromagnetic waves and phase shifts can be modulated by exploiting an anisotropic space layer in a polarization F-P filter. Birefringence of the anisotropic space layer provided a sophisticated phase modulation with varied incidence angles over a broad range, resulting in a wide-angle phase shift. This new concept would be useful for designing optical components with isotropic and anisotropic materials.

• Advances in materials Research
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• v.9 no.1
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• pp.15-32
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• 2020

In this article, an analytical solution is presented for the steady-state axisymmetric thermal stress distributions in a composite hollow cylinder. The cylinder is composed of two isotropic and anisotropic materials which is subjected to the thermal boundary conditions of convective as well as radiative heating and cooling on the inner and outer surfaces, respectively. The solution of the temperature is obtained by means of Bessel functions and the thermal stresses are developed using Potential functions of displacement. Numerical results are derived for a cylinder which is similar to a gas turbine combustor and showed that the maximum temperature and thermal stresses (radial, hoop, axial) occurred in the middle point of cylinder and the values of thermal stresses in anisotropic cylinder are more than the isotropic cylinder. It is worthy to note that the values of the thermal conditions which estimated in this research, not to be presented in any other papers but these values are very accurate in calculation.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2003.10a
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• pp.75-78
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• 2003

In order to describe the Bauschinger and transient behavior of orthotropic fiber-reinforced composites, a combined isotropic-kinematic hardening law based on the non-linear kinematic hardening rule was considered here, in particular, based on the Chaboche type law. In this modified constitutive law, the anisotropic evolution of the back-stress was properly accounted for. Also, to represent the orthotropy of composite materials, Hill's 1948 quadratic yield function and the orthotropic elasticity constitutive equations were utilized. Furthermore, the numerical formulation to update the stresses was also developed based on the incremental deformation theory for the boundary value problems. Numerical examples confirmed that the new law based on the anisotropic evolution of the back-stress complies well with the constitutive behavior of highly anisotropic materials such as fiber-reinforced composites.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.10 no.1
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• pp.38-46
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• 2011

A study was performed to investigate the dynamic behaviors of fiber-reinforced composite materials subjected to transversely low-velocity impact. For this purpose, the simulation of modified beam finite element based on higher order beam theory for two(isotropic and anisotropic) materials is carried out according to the changes of material property, stacking sequence, geometric dimension and impact velocity of steel ball, etc. Main composite materials for simulation are composed of $[0^{\circ}/90^{\circ}/0^{\circ}/-90^{\circ}/0^{\circ}]_{2s}$, $[0^{\circ}/90^{\circ}/0^{\circ}/-90^{\circ}/0^{\circ}]_s$ and $[0^{\circ}/45^{\circ}/0^{\circ}/-45^{\circ}/0^{\circ}]_{2s}$, $[0^{\circ}/45^{\circ}/0^{\circ}/-45^{\circ}/0^{\circ}]_s$ stacking sequences. The effectiveness of this simulation for qualitative and quantitative evaluations in composite materials subjected to foreign object impact was established.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2003.10a
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• pp.144-147
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• 2003

In order to evaluate spring-back behavior in automotive sheet forming processes, a panel shape idealized as a SS-rail has been investigated. After spring-back kas been predicted fer SS-rails using the finite element analysis, results has been compared with experimental measurements for three automotive sheets. To account for hardening behavior such as the Bauschinger and transient effects in addition to anisotropic behavior, the combined isotropic-kinematic hardening law based on the Chaboche type single-surface model and a recently developed non-quadratic anisotropic yield function have been utilized, respectively.