• Steel and Composite Structures
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• 제31권4호
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• pp.387-396
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• 2019

This paper deals with the effect of ply orientation and control gain on tip transverse displacement of functionally graded beam layer for both active constrained layer damping (ACLD) and passive constrained layer damping (PCLD) system. The functionally graded beam is taken as host beam with a bonded viscoelastic layer in ACLD beam system. Piezoelectric fiber reinforced composite (PFRC) laminate is a constraining layer which acts as actuator through the velocity feedback control system. A finite element model has been developed to study actuation of the smart beam system. Fractional order derivative constitutive model is used for the viscoelastic constitutive equation. The control voltage required for ACLD treatment for various symmetric ply stacking sequences is highest in case of longitudinal orientation of fibers of PFRC laminate over other ply stacking sequences. Performance of symmetric and anti-symmetric ply laminates on damping characteristics has been investigated for smart beam system using time and frequency response plots. Symmetric and anti-symmetric ply laminates significantly reduce the amplitude of the vibration over the longitudinal orientation of fibers of PFRC laminate. The analysis reveals that the PFRC laminate can be used effectively for developing very light weight smart structures.

• Advances in Computational Design
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• 제7권2호
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• pp.99-112
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• 2022

This research has been devoted to examine nonlinear static bending analysis of smart beams with nano dimension exposed to thermal environment. The beam elastic properties are corresponding to piezo-magnetic material of different compositions. The large deflection analysis of the beam has been performed assuming that the beam is exposed to transverse uniform pressure. Based on the rule of Hamilton, the governing equations have been derived for a nonlocal thin beam and solved using differential quadrature method. Temperature variation effect on nonlinear deflection of the smart beams has been studied. Also, the beam deflection is shown to be affected by electric voltage, magnetic intensity and material composition.

• Steel and Composite Structures
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• 제35권5호
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• pp.635-640
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• 2020

The buckling analysis of the embedded sinusoidal piezoelectric beam is evaluated using numerical method. The smart beam is subjected to external voltage in the thickness direction. Elastic medium is simulated with two parameters of spring and shear. The structure is modelled by sinusoidal shear deformation theory (SSDT) and utilizing energy method, the final governing equations are derived on the basis of piezo-elasticity theory. In order to obtaining the buckling load, the differential quadrature method (DQM) is used. The obtained results are validated with other published works. The effects of beam length and thickness, elastic medium, boundary condition and external voltage are shown on the buckling load of the structure. Numerical results show that with enhancing the beam length, the buckling load is decreased. In addition, applying negative voltage, improves the buckling load of the smart beam.

• 소음진동
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• 제11권2호
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• pp.257-264
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• 2001

In this research, piezoelectric smart structures are applied for SEA(Statistical Energy Analysis), which is well known approach for high frequency analysis. A new input power measurement based on piezoelectric electrical power measurement is proposed and compared with the conventional method in SEA. As an example, a simple aluminum beam on which piezoelectric actuator is attached is considered. By measuring the electrical impedance and electrical current of the piezoelectric actuator, the electrical power given on the actuator is found and this is In turn converted into the mechanical energy. From the measured value of the stored energy of the beam, the Internal loss factor is calculated and this value shows a good agreement with that given by the conventional method as well as the theoretical value. To compare the coupling loss factor, L-shape beam system which consists of a aluminum beam subsystem and a steel beam subsystem coupled by three pin is taken as second example. The input power and stored energy of each subsystem are found by the proposed approach. The coupling loss factor found by the electrical input power obtained from the piezoelectric actuator exhibits similar trend to the value found by the conventional method as well as the theoretical value. In conclusion, the use of SEA for high frequency application of piezoelectric smart structures is Possible. Especially, the input power that is essential for SEA can be found accurately by measuring the electrical input power of the piezoelectric actuator.

• Smart Structures and Systems
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• 제4권1호
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• pp.67-84
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• 2008

The present contribution is concerned with the static and dynamic stability of a piezo-laminated Bernoulli-Euler beam subjected to an axial compressive force. Recently, an inconsistent derivation of the equations of motions of such a smart structural system has been presented in the literature, where it has been claimed, that an axial piezoelectric actuation can be used to control its stability. The main scope of the present paper is to show that this unfortunately is impossible. We present a consistent theory for composite beams in plane bending. Using an exact description of the kinematics of the beam axis, together with the Bernoulli-Euler assumptions, we obtain a single-layer theory capable of taking into account the effects of piezoelectric actuation and buckling. The assumption of an inextensible beam axis, which is frequently used in the literature, is discussed afterwards. We show that the cited inconsistent beam model is due to inadmissible mixing of the assumptions of an inextensible beam axis and a vanishing axial displacement, leading to the erroneous result that the stability might be enhanced by an axial piezoelectric actuation. Our analytical formulations for simply supported Bernoulli-Euler type beams are verified by means of three-dimensional finite element computations performed with ABAQUS.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2015년도 추계 학술논문 발표대회
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• pp.168-169
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• 2015

SMART Frame is a composite precast concrete structure system to deliver the advantages of both steel frame and reinforced concrete. Many studies have established to date that SMART Frame is more advantageous than conventional frame-type structure in terms of structural stability, constructability, economic viability as well as reduction of construction schedule. However, such studies have focused primarily on wall-type or flat slab-type apartment housing structures, failing to include Rahmen structures in their scope. Accordingly, this study aims to analyze the benefits of potential application of SMART Frame to RC Rahmen structures. As the structural stability and constructability of SMART Frame is already proven, this study reviews its benefits from the perspective of cost reduction. Conclusion of this study will be used subsequently in predicting the benefits of SMART Frame when it is adapted to RC Rahmen structures.

• Steel and Composite Structures
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• 제23권3호
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• pp.339-350
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• 2017

In this paper, various nonlocal higher-order shear deformation beam theories that consider the size dependent effects in Functionally Graded Material (FGM) beam are examined. The presented theories fulfill the zero traction boundary conditions on the top and bottom surface of the beam and a shear correction factor is not required. Hamilton's principle is used to derive equation of motion as well as related boundary condition. The Navier solution is applied to solve the simply supported boundary conditions and exact formulas are proposed for the bending and static buckling. A parametric study is also included to investigate the effect of gradient index, length scale parameter and length-to-thickness ratio (aspect ratio) on the bending and the static buckling characteristics of FG nanobeams.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2014년도 추계 학술논문 발표대회
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• pp.203-204
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• 2014

Unlike other members, beams have various cross-sections and they have an important role of delivering the load of slabs. A beam form neighbors the columns and slabs, which makes it difficult to be installed. In a conventional way to exclusively use the form after concrete pouring, the form and a support should be both removed. Then, the support should reinstalled to sustain the stripping time of form, resulting in a structural issue. To solve such structural problem, the study proposes SMART beam form that uses filler panels and supports for filler. The floor filler panels and supports for filler are not removed after concrete curing, to conform to the stripping time of supports. Thus, any structural problem such as cracks and reduction of compressive strength owing to the gap of load bearing capacity can be prevented. The study results will be used as cases for studies on productivity analyses.

• 대한기계학회논문집A
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• 제34권8호
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• pp.1105-1111
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• 2010

한국원자력연구원은 전력생산과 해수담수화를 동시에 수행하고 친환경적인 SMART 원자로를 개발하였다. SMART 원자로의 여러 구조물 중에 제어봉 구동 장치(CRDM)는 제어봉의 삽입 량을 조절하여 원자로의 출력을 조정하고 비상시 제어봉을 긴급 삽입하여 원자로를 정지시키기 위한 기기이다. 본 연구의 목적은 제어봉 구동 장치의 구조적 건전성을 확보하기 위해서 동특성해석을 수행하는 것이다. 또한 향후 내진해석에 활용될 단순모델의 활용을 위해 상세모델과의 비교, 검증을 수행하였다. 해석은 유한요소 해석기법을 활용하였고 상용해석 프로그램인 ABAQUS 와 ANSYS V12 를 사용하였다. 유한요소 해석모델은 상세모델인 3-D Solid 모델과 단순모델인 Beam 모델을 작성하여 비교하였고 추가로 단순모델을 오일러 보인 Beam4 요소와 티모센코 보인 Beam188 요소로 작성하여 비교 검토하였다. 향후 SMART 원자로집합체의 단순모델을 작성하여 내진해석 등 다양한 해석에 활용될 계획이므로 단순모델은 상세모델과의 오차를 줄이기 위해서 모델 보정(model updating)이 수행되었다.

• 산업기술연구
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• 제29권B호
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• pp.127-131
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• 2009

This paper presents the development of smart counting system that is proper for grains with uneven unit weight or shape. This device can detect the small differences of a light beam and count the pulse from wave shape control, when the grain is going on the light screen, which is made by the light beam screen sensor. It can, different from the former conventional device, distinct the uneven grains for counting detect, by using the dedicated hardware and the software algorithm of the light sensor.