• Earthquakes and Structures
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• 제14권2호
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• pp.103-115
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• 2018

In this work, a simple but accurate hyperbolic plate theory for the free vibration analysis of functionally graded material (FGM) sandwich plates is developed. The significant feature of this formulation is that, in addition to including the shear deformation effect, it deals with only 3 unknowns as the classical plate theory (CPT), instead of 5 as in the well-known first shear deformation theory (FSDT) and higher-order shear deformation theory (HSDT). A shear correction factor is, therefore, not required. Two common types of FGM sandwich plates are considered, namely, the sandwich with the FGM face sheet and the homogeneous core and the sandwich with the homogeneous face sheet and the FGM core. The equation of motion for the FGM sandwich plates is obtained based on Hamilton's principle. The closed form solutions are obtained by using the Navier technique. The fundamental frequencies are found by solving the eigenvalue problems. Numerical results of the present theory are compared with the CPT, FSDT, order shear deformation theories (HSDTs), and 3D solutions. Verification studies show that the proposed theory is not only accurate and simple in solving the free vibration behaviour of FGM sandwich plates, but also comparable with the higher-order shear deformation theories which contain more number of unknowns.

• 전자공학회논문지B
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• 제33B권5호
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• pp.60-72
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• 1996

In this paper, a enw model-base three-dimensional (3-D) object recognition mehtod using hopfield network is proposed. To minimize deformation of feature values on 3-D rotation, we select 3-D shape features and 3-D relational features which have rotational invariant characteristics. Then these feature values are normalized to have scale invariant characteristics, also. The input features are matched with model features by optimization process of hopjfield network in the form of two dimensional arrayed neurons. Experimental results on object classification and object matching with the 3-D rotated, scale changed, an dpartial oculued objects show good performance of proposed method.

• 암석학회지
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• 제9권4호
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• pp.254-270
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• 2000

예천전단대가 통과하고 북동-남서 방향의 구조선과 동처 방향의 구조선이 발달하고 있는 경북 봉화군 상운면지역에서 북부 소백산육괴의 지질구조를 규명하기 위해 이 지역의 주 구성암류인 선캠브리아기 원남층과 중생대 각섬석 화강암에 대한 암석구조를 연구하였다. 이 지역의 지질구조는 원남층의 편마면 내지 편리면이 형성된 이후 적어도 네 번의 변형단계(예천전단대 형성과 관련된 D2 연성전단변형 이전에 한 번의 변형작용과 이후에 적어도 두 번의 변형작용)를 걸쳐 형성되었다. 북동-남서 방향의 구조선과 동서 방향의 구조선은 하나의 거대한 완사 내지 개방형 F4 습곡작용에 의해 형성되었으며, D4 변형 이전에 이들 구조선은 F4 습곡축부의 방향과 평행한 동북동서남서 방향이었던 것으로 해석된다. D4 변형 이전의 각 변형단계 별 구조적 특성 및 상대적인 발생시기는 다음과 같다: Dl 변형-준 수평적인 습곡축과 고각으로 경사하는 습곡축면을 갖는 동북동 방향의 등사습곡과 부딩구조 형성기; D2 변형-북쪽으로 경사하는 원남층의 우세한 엽리면의 상부가 동북동쪽으로 이동하는 대규모의 우수 주향 이동성의 연성전단운동에 의한 압쇄구조면과 신장선구조 그리고 Z자형 비대칭 습곡형성기(중생대 각섬석 화강암이 관입된 이후); D3 변형-원남층의 우세한 엽리면의 상부가 경사 방향(북북서 방향)으로 떨어지는 정전단운동에 의한 준 수령적인 습곡축과 습곡축면을 갖는 동북동 방향의 S자형 비대칭 습곡 형성기. 이러한 연구결과는 신동-봉화 연결선을 경계로 지구조선의 방위가 북동-남서 방향에서 동-서 방향으로 전환되는 북부 소백산육괴와 옥천대 북동부의 지구조 발달과정을 해석하는데 유용하게 활용될 것으로 기대된다.

• 한국해양공학회지
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• 제17권1호
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• pp.80-85
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• 2003

In this study, we developed an analysis method of plate forming by induction heating, verifying the effectiveness of the present method through a series of experiments. The phenomena of the induction heating involves a 3D transient problem, coupled with electromagnetic, heat transfer, and elastoplastic large deformation analyses. To solve the problem, or present an appropriate model and an integrated system. Using the present analysis model, or can estimate the plate deformation in heating without experiments and simulate the plate bending process of induction heating.

• 한국지구물리탐사학회:학술대회논문집
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• 한국지구물리탐사학회 2003년도 Proceedings of the international symposium on the fusion technology
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• pp.129-141
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• 2003

The precise prediction of ground displacement plays an important role in planning and constructing tunnels. In this study, an equation for predicting the surface and crown settlement is suggested by examining the theories of ground movement caused by tunnel excavation. From the 3D numerical modeling, the reinforcement effect of UAM (Umbrella Arch Method) is quantitatively analyzed with respect to deformation modulus and overburden. By using a regression technique for the numerical results, an equation for predicting the settlement is suggested.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 추계학술대회
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• pp.1139-1144
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• 2003

This paper addresses a theoretical study to calculate the amount of the stored energy due to vacancies during high-strain-rate deformation. The study concerns the role of excess vacancies, which can play an important role to increase the amount of stored energy. Molecular dynamics simulation using a 3D model is carried out and the result clearly shows that the excess vacancies are credited to generation of the stored energy.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part 1
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• pp.260-261
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• 2006

The behaviour of steel powder compacts during sintering has been investigated by dilatometry and X-ray computed microtomography. Dilatometry measurements showed that the anisotropic deformation results from various phenomena arising at different moments of the cycle including the delubrication stage. Microtomography provided 3D images of the microstructure induced by prior die pressing and its changes throughout sintering. Finally a schematic description of the main phenomena responsible for the deformation of metal powder compacts during sintering is proposed.

• 한국수학교육학회지시리즈B:순수및응용수학
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• 제10권2호
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• pp.119-126
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• 2003

In this paper, when N is a compact Riemannian manifold, we considered the positive time solution to equation $\Box_gu(t,x)-c_nu(t,x)+c_nu(t,x)^{(n+3)/(n-1)}$ on M ＝$(-{\infty},+{\infty})\;{\times}_f\;N$, where $c_n$ ＝(n－1)/4n and $\Box_{g}$ is the d'Alembertian for a Lorentzian warped manifold.

• 해양환경안전학회:학술대회논문집
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• 해양환경안전학회 2017년도 공동학술발표회
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• pp.265-265
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• 2017

• 대한기계학회논문집A
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• 제27권2호
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• pp.239-246
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• 2003

This paper proposes engineering estimation equations of elastic-plastic J and COD fur axial through-wall cracked pipes under internal pressure. Based on detailed 3-D FE results based on deformation plasticity, the plastic influence functions for fully plastic J and COD solutions are tabulated as a function of the mean radius-to-thickness ratio, the normalized crack length. and the strain hardening. Based on these results, the GE/EPRI-type J and COD estimation equations are proposed and validated against the 3-D FE results based on deformation plasticity. For more general application to general stress-strain laws or to complex loading, the developed GE/EPRI-type solutions are re-formulated based on the reference stress concept. Such a reformulation provides simpler equations for J and COD, which are then further extended to combined internal pressure and bending. The proposed reference stress based J and COD estimation equations are compared with elastic-plastic 3-D FE results using actual stress-strain data for Type 316 stainless steels. The FE results for both internal pressure cases and combined internal pressure and bending cases compare very well with the proposed J and COD estimations.