• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.07a
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• pp.365-366
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• 2005

PZT films are the most intensively investigated because PZT has advantages such as low processing temperature and large remnant values. In this paper, the microstructure and electric properties of $Pb(Zr_x,Ti_{(1-x)})O_3/BaTiO_3$ heterolayered thick films with Zr mole ranging from 30 to 70 % screen printed onto a alumina substrate were studied. $Pb(Zr_x,Ti_{(1-x)})O_3$ and $BaTiO_3$ powders were prepared by the sol-gel method. The $BaTiO_3$ powders were calcined at $700^{\circ}C$ for 2 hours. Structural properties of $Pb(Zr_x,Ti_{(1-x)})O_3/BaTiO_3$ multilayered thick films were investigated. As a result of the X-ray diffraction (XRD) analysis, $Pb(Zr_x,Ti_{(1-x)})O_3/BaTiO_3$ exhibited a perovskite polycrystalline phase without pyrochlore phase or any preferred orientation.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.06a
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• pp.331-332
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• 2006

Ag-ceramic composite materials were investigated as internal electrodes for multilayer ceramic actuators (MLCA). Ag-ceramic pastes were prepared by adding PZT-based ceramic powders to a Ag patse in a range of 0 to 50 wt.%. PZT/Ag-PZT multilayered laminates were fabricated by tape casting and fired at low temperatures below $950^{\circ}C$. The addition of ceramic into the Ag electrode resulted in a decrease in the thermal expansion mismatch between the electrode and the ceramic sheet. The maximum strain of PZT/Ag-PZT multilayered actuators were $9{\times}10^{-4}$ under an electric field of 2.5MV/m. In conclusion, Ag-PZT composite materials are efficient for low cost piezoelectric MLCAs.

• Journal of the Korean Vacuum Society
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• v.6 no.S1
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• pp.80-88
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• 1997

The attempt to enhance the strength of materials has been an important subject for materials engineering and scientists. The strength of materials is termed as the ability to support high load without excessive deformation and without breaking catastrophically. The control of dislocation densities and barriers to the movement of dislocations have been considered to be the important methods for the strengthening materials. One of the approaches is mechanical blocking of dislocations by alternately depositing material layers. The typical structure of materials is multilayered and laminated composites. The thickness of each layer is typically in the range of nanometer. Ton avoid confusion with other terminology they may be defined as microlaminate composite materials. The manufacturing process of multilayered laminate structure will be introduced. And the current theoretical theories will be reviewed in view of strengthening of microlaminte composite materials.

• Structural Engineering and Mechanics
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• v.63 no.4
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• pp.481-495
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• 2017

The present article examines the static response of multilayered magneto-electro-elastic (MEE) beam in thermal environment through finite element (FE) methods. On the basis of the minimum total potential energy principle and the coupled constitutive equations of MEE material, the FE equilibrium equations of cantilever MEE beam is derived. Maxwell's equations are considered to establish the relation between electric field and electric potential; magnetic field and magnetic potential. A simple condensation approach is employed to solve the global FE equilibrium equations. Further, numerical evaluations are made to examine the influence of different in-plane and through-thickness temperature distributions on the multiphysics response of MEE beam. A parametric study is performed to evaluate the effect of stacking sequence and different temperature profiles on the direct and derived quantities of MEE beam. It is believed that the results presented in this article serve as a benchmark for accurate design and analysis of the MEE smart structures in thermal applications.

• Structural Engineering and Mechanics
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• v.64 no.6
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• pp.751-763
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• 2017

This article deals with the buckling behaviour of multilayered magneto-electro-elastic (MEE) plate subjected to uniaxial and biaxial compressive (in-plane) loads. The constitutive equations of MEE material are used to derive a finite element (FE) formulation involving the coupling between electric, magnetic and elastic fields. The displacement field corresponding to first order shear deformation theory (FSDT) has been employed. The in-plane stress distribution within the MEE plate existing due to the enacted force is considered to be equivalent to the applied in-plane compressive load in the pre-buckling range. The same stress distribution is used to derive the potential energy functional. The non-dimensional critical buckling load is accomplished from the solution of allied linear eigenvalue problem. Influence of stacking sequence, span to thickness ratio, aspect ratio, load factor and boundary condition on critical buckling load and their corresponding mode shape is investigated. In addition, static deflection of MEE plate under the sinusoidal and the uniformly distributed load has been studied for different stacking sequences and boundary conditions.

• Structural Engineering and Mechanics
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• v.42 no.5
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• pp.729-745
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• 2012

This study presents dynamic analysis of laminated beams traversed by moving loads using a multilayered beam element based on the first-order shear deformation theory. The present element consists of N layers with different thickness and material property, and has (3N + 7) degrees of freedom corresponding three axial, four transversal, and 3N rotational displacements. Delamination and interfacial slip are not allowed. Comparisons with analytical and/or numerical results available in literature for some illustrative examples are made. Numerical results for natural frequencies, deflections and stresses of laminated beams are given to explain the effect of load speed, lamina layup, and boundary conditions.

• Structural Engineering and Mechanics
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• v.24 no.6
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• pp.727-740
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• 2006

A simple plane-strain solution is derived in this paper for the functionally graded multilayered isotropic elastic cylinder under static deformation. The solution is obtained using method of separation of variables and is expressed in terms of the summation of the Fourier series in the circumferential direction. While the solution for order n = 0 corresponds to the axisymmetric deformation, that for n = 2 includes the special deformation frequently utilized in the upper and lower bounds analysis. Numerical results for a three-phase cylinder with a middle functionally graded layer are presented for both axisymmetric (n = 0) and general (n = 2) deformations, under either the traction or displacement boundary conditions on the surface of the layered cylinder. The solution to the general deformation case (n = 2) is further utilized for the first time to find the upper and lower bounds of the effective shear modulus of the layered cylinder with a functionally graded middle layer. These results could be useful in the future study of cylindrical composites where FGMs and/or multilayers are involved.

• Journal of the Korean Society for Precision Engineering
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• v.15 no.9
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• pp.50-55
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• 1998

A thermal printing head is used for heat transcription printing of facsimile or printer. The thermal printing head has multilayered thin films and heaters lined up. Thermal analysis of thermal printing head is important for a design of thermal printing head. Since the heating charateristics of thermal printing head is dependent on the thermal conductivities of multilayerd material, this study made numerical analysis for three dimensional transient heat conduction in mutilayered films by the finite difference method and investigated the effect of various thermal conductivities of thin films. The results of this study will be used to design thermal printing head and select the materials for thermal printing head.

• Proceedings of the International Microelectronics And Packaging Society Conference
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• 2002.05a
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• pp.134-137
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• 2002

A new LTCC material in the $PbWO_4-TiO_2-B_2O_3-CuO$ system was developed. The developed material can be sintered at $850^{\circ}C$ and its dielectric properties are $\varepsilon_r=20-25, Q\timesf_o=30000~50000GHz$ , and $\tau_f=0.2~30ppm/^{\circ}C$, depending on the components moi ratio. Due to its low sintering temperature and microwave dielectric properties, the developed material can be used as a LTCC substrate for fabrication of multilayered microwave communication module set. In present study, using this material, tape casting condition was established. With this processing condition, a T-resonator was fabricated and its electrical properties were examined. Also, a 2-Pole band pass filter was fabricated and its frequency characteristics were compared with simulation results.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.30 no.5
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• pp.389-396
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• 2017

Peridynamics has been widely used in the dynamic fracture analysis of brittle materials. Recently, various crack patterns(compact region, floret, Hertz-type crack, etc.) of multilayered glass structures in experiments(Bless et al. 2010) were implemented with a bond-based peridynamic simulation(Bobaru et al.. 2012). The actual glass layers are bound with thin elastic interlayer material while the interlayer is missing from the peridynamic model used in the previous numerical study. In this study, the peridynamic interlayer modeling for the multilayered structures is proposed. It requires enormous computational time and memory to explicitly model very thin interlayer materials. Instead of explicit modeling, fictitious peridynamic particles are introduced for modeling interlayer materials. The computational efficiency and accuracy of the proposed peridynamic interlayer model are verified through numerical tests. Furthermore, preventing penetration scheme based on short-range interaction force is employed for the multilayered structure under compression and verified through parametric tests.