• Proceedings of the Computational Structural Engineering Institute Conference
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• 2001.10a
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• pp.45-52
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• 2001

A series of unreinforced masonry (URM) walls were analytically investigated for a limited version of seismic in-plane performance. For this URM walls were assumed to be an elastic continuum and modeled as isotropic plane stress elements within which the nature of cracking was propagated. Accordingly, cracking mode of behavior in URM was modeled by smeared-crack approach. Total of 70 cases were considered for various parameters such as axial load ratio, aspect ratio and effective section area ratio due to the existence of opening, etc. The analysis results indicated a general tendency in base shear coefficient and deformability of URM walls for these variables.

• Advances in nano research
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• v.7 no.5
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• pp.311-324
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• 2019

The present study aims to evaluate the nonlinear and post-buckling behaviors of orthotropic graphene sheets exposed to end-shortening strain by implementing a semi-Galerkin technique, as a new approach. The nano-sheets are regarded to be on elastic foundations and different out-of-plane boundary conditions are considered for graphene sheets. In addition, nonlocal elasticity theory is employed to achieve the post-buckling behavior related to the nano-sheets. In the present study, first, out-of-plane deflection function is considered as the only displacement field in the proposed technique, which is hypothesized by an appropriate deflected form. Then, the exact nonlocal stress function is calculated through a complete solution of the von-Karman compatibility equation. In the next step, Galerkin's method is used to solve the unknown parameters considered in the proposed technique. In addition, three different scenarios, which are significantly different with respect to concept, are used to satisfy the natural in-plane boundary conditions and completely attain the stress function. Finally, the post-buckling behavior of thin graphene sheets are evaluated for all three different scenarios, and the impacts of boundary conditions, polymer substrate, and nonlocal parameter are examined in each scenario.

• Proceedings of the Korea Concrete Institute Conference
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• 2000.10a
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• pp.211-216
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• 2000

Numerical studies were carried out to develop the moment magnifier method for long-term behavior of flat plates, subjected to combined in-plane compressive and transverse loads. Nonlinear finite element analyses were performed for the numerical studies. Through the numerical studies, the long term behavior of the flat plate subjected to uniform or nonuniform floor load was investigated, and creep effects on the degradation of strength and stiffness of the slabs were examined. As the result, the creep factor was developed to epitomizes with creep effect on the flat plate. The moment magnifier method using the creep factor was developed for long-term behavior of flat plates. Also, the design examples are shown for verification of proposed design method.

• Journal of Welding and Joining
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• v.8 no.3
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• pp.79-88
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• 1990

Welded joint often contains soft or softened regions such as the HAZ of TMCP steel welded with high heat input. In this study, the equivalent yield strength of plate structure containing softened region was predicted by FEM analysis, and its incremental behavior was explained with the results of the analysis. The calculated results of yield strength indicated the following for the plate structures. 1) As the softened region starts to yield, shear stress begins to build up along the boundary between base metal and softened region. This results in multi-axial stress condition which gives restraint on the softened region. 2) Restraint effect has a significant influence on the distribution of the shear stress, the nominal stress, and the strain. 3) The yielding behavior of softened region becomes the same as that of base metal when both ratios of length to width and thickness to width of softened region are larger than 30 and 13 respectively.

• Steel and Composite Structures
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• v.19 no.1
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• pp.153-171
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• 2015

Twelve large-scale composite deck slabs were instrumented and tested in a cantilever diaphragm configuration to assess the effect of fibers and welded wire mesh (WWM) on the in-plane shear capacity of composite deck slabs. The slabs were constructed with reentrant decking profile and reinforced with different types and dosages of secondary reinforcements: Conventional welded wire mesh (A142 and A98); synthetic macro-fibers (dosages of $3kg/m^3$ and $5.3kg/m^3$); and hooked-end steel fibers with a dosage of $15kg/m^3$. The deck orientation relative to the main beam (strong and weak) was also considered in this study. Fibers and WWM were found efficient in distributing the applied load to the whole matrix, inducing multiple cracking, thereby enhancing the strength and ductility of composite deck slabs. The test results indicate that fibers increased the slab's ultimate in-plane shear capacity by up to 29% and 50% in the strong and weak directions, respectively. WWM increased the ultimate in-plane shear capacity by up to 19% in the strong direction and 9% in the weak direction. The results suggest that discrete fibers can provide comparable diaphragm behavior as that with the conventional WWM.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.27 no.1
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• pp.42-47
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• 2003

Nonlinear models for a thin ring rotating at a constant speed are developed. The geometric nonlinearity of displacements is considered by adopting the Lagrange strain theory for the circumferential strain. By using Hamilton’s principle, the coupled nonlinear partial differential equations are derived, which describe the out-of-plane and in-plane bending, extensional and torsional motions. The natural frequencies are calculated from the linearized equations at various rotational speeds. Finally, the computation results from the nonlinear models are compared with those from a linear model. Based on the comparison, this study recommends which model is appropriate to describe the behavior of the rotating ring.

• Proceedings of the Korea Concrete Institute Conference
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• 1990.04a
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• pp.102-107
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• 1990

The research program is directed at studying the behavior and the strength of reinforced concrete slabs subjected to certain combination of punching shear and in-plane tension. Major variables to be investigated are the shear span to depth ratio of reinforced concrete slabs and the degree of the in-plane tensile force which is acting tangent to the slabs. The experimental results are used for understanding of the degree of the interaction between the two loadings, and for developing a new practical design equation.

• 한국정보디스플레이학회:학술대회논문집
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• 2003.07a
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• pp.1092-1095
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• 2003

A driving mechanism and excellent features for an in-plane switching twisted nematic liquid crystal mode (IT mode) that could possibly improve the viewing-angle and color shift characteristics and the cell gap error tolerance is proposed. .It is important that the surface azimuthal anchoring strength of the liquid crystal cell differs at the upper and lower substrates. Furthermore. as a rubbing-free LCD. amorphously aligned in-plane switching twisted nematic mode (a-IT mode) is also demonstrated.

• Geomechanics and Engineering
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• v.5 no.6
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• pp.499-517
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• 2013

In order to investigate shear behavior of granular materials due to excavation and associated unloading actions, load-controlled plane strain compression tests under decreasing confining pressure were performed under drained conditions and the results were compared with the conventional plane strain compression tests. Four types of granular material consisting of two quartz sands and two glass beads were used to investigate particle shape effects. It is clarified that macro stress-strain behavior is more easily influenced by stress level and stress path in sands than in glass beads. Development of localized deformation was analyzed using photogrammetry method. It was found that shear bands are generated before peak strength and shear band patterns vary during the whole shearing process. Under the same test condition, shear band thickness in the two sands was smaller than that in one type of glass beads even if the materials have almost the same mean particle size. Shear band thickness also decreased with increase of confining pressure regardless of particle shape or size. Local maximum shear strain inside shear band grew approximately linearly with global axial strain from onset of shear band to the end of softening. The growth rate is found related to shear band thickness. The wider shear band, the relatively lower the growth rate. Finally, observed shear band inclination angles were compared with classical Coulomb and Roscoe solutions and different results were found for sands and glass beads.

• Journal of the Korean Mathematical Society
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• v.43 no.6
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• pp.1169-1181
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• 2006

We introduce a new biharmonic kernel for the upper half plane, and then study the properties of its relevant potentials, such as the convergence in the mean and the boundary behavior. Among other things, we shall see that Fatou's theorem is valid for these potentials, so that the biharmonic Poisson kernel resembles the usual Poisson kernel for the upper half plane.