• Structural Engineering and Mechanics
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• 제85권5호
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• pp.593-605
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• 2023

This work presents a comparison between analytical and finite element analysis for bending of porous sandwich functionally graded material (FGM) plates. The plate is rectangular and simply supported under static sinusoidal loading. Material properties of FGM are assumed to vary continuously across the face sheets thickness according to a power-law function in terms of the volume fractions of the constituents while the core is homogeneous. Four types of porosity are considered. A refined higher-order shear with normal deformation theory is used. The number of unknowns in this theory is five, as against six or more in other shear and normal deformation theories. This theory assumes the nonlinear variation of transverse shear stresses and satisfies its nullity in the top and bottom surfaces of the plate without the use of a shear correction factor. The governing equations of equilibrium are derived from the virtual work principle. The Navier approach is used to solve equilibrium equations. The constitutive law of the porous FGM sandwich plate is implemented for a 3D finite element through a subroutine in FORTRAN (UMAT) in Abaqus software. Results show good agreement between the finite element model and the analytical method for some results, but the analytical method keeps giving symmetric results even with the thickness stretching effect and load applied to the top surface of the sandwich.

• Structural Engineering and Mechanics
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• 제73권3호
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• pp.259-269
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• 2020

In this paper, bending-stretching analysis of thick functionally graded piezoelectric rectangular plates is studied using the higher-order shear and normal deformable plate theory. On the basis of this theory, Legendre polynomials are used for approximating the components of displacement field. Also, the effects of both normal and shear deformations are encountered in the theory. The governing equations are derived using the principle of virtual work and variational approach. It is assumed that plate is made of piezoelectric materials with functionally graded distribution of material properties. Hence, exponential function is used to modify mechanical and electrical properties through the thickness of the plate. Finally, the effect of material properties, electrical boundary conditions and dimensions are investigated on the static response of plate. Also, it is shown that results of the presented model are close to the three dimensional elasticity solutions.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2004년도 봄 학술발표회 논문집
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• pp.25-32
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• 2004

In this proposed work new finite element model for multi-delaminated plates is proposed. In the current analysis procedures of multi-delaminated plates, plate element based on Mindlin plate theory is used in order to obtain accurate results of out-of-plane displacement of thick plate. And for delaminated region, plate element based on Kirchhoff plate theory is considered. To satisfy the displacement continuity conditions, displacement vector based on Kirchhoff theory is transformed to displacement of transition element. The numerical results show that the effect of delaminations on the modal parameters of delaminated composites plates is dependent not only on the size, the location and the number of the delaminations but also on the mode number and boundary conditions. Kirchhoff based model have higher natural frequency than Mindlin based model and natural frequency of the presented model is closed to Mindlin based model.

• 대한기계학회논문집A
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• 제22권3호
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• pp.569-578
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• 1998

The mode I and II stress intensity factors have been calculated theoretically for the cracked plate reinforced with a plate by symmetric spot welding under remote mixed mode loading. This is the extension of authors' previous work for the reinforced cracked plate under remote normal stress. Regardless of loading types, the reinforcement effect gets better as one joining spot is closer to the crack tip and the others are closer to the crack surface, and optimum number of the joining spots can be existed. For the present model, the remote loading parallel to crack surface produces the mode I stress intensity factor.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2000년도 춘계학술발표대회 논문집
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• pp.5-8
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• 2000

This paper presents the results of an elastic buckling analysis of orthotropic plate under in-plane linearly distributed forces. The analytical solution for the orthotropic plate whose boundaries were assumed to be simply supported was derived in the previous work. In this study the loaded edges of plate are assumed to be simply supported and other two edges are assumed to be fixed. For the buckling analysis Rayleigh-Ritz method is employed. Graphical form of results for finding the elastic buckling strength of orthotropic plate under in-plane linearly distributed forces is presented.

• 한국소음진동공학회논문집
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• 제15권1호
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• pp.81-86
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• 2005

In this work, we propose a new ultrasonic damage inspection method in plate structures. The proposed method employs an OPMT(orientation-adjustable patch-type magnetostrictive transducer) in order to make the ultrasonic waves directed to a specific target point. For experiments, virtual grid points were set up at every 50 mm in an aluminum plate and two OPMTs were used for inspection. If there exists a crack in a plate, the reflected Lamb wave from the crack is measured in addition to the direct waves from the transmitting transducer to the receiving transducer.

• Journal of Welding and Joining
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• 제21권1호
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• pp.54-59
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• 2003

In the present work, a formula for plate deformation produced by line heating, in terms of process parameters such as heat input and plate dimensions, is developed analytically using an eigenstrain concept. The residual deformation that was due to thermal process was depends on the magnitude and region of plastic strains at heating zone. The magnitude of plastic strains was determined by disk model and its region was calculated using the Rosenthal"s solution. The vertical displacement of the plate was analyzed by using an infinite laminated plate theory to consider a cuboidal inclusion with an eigenstrain. Comparison of the calculated results and experimental data shows the accuracy and validity of proposed method.thod.

• 한국소음진동공학회논문집
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• 제21권3호
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• pp.220-226
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• 2011

This paper presents the novel work for source localization of serial multiple impacts in a plate sructure. It is difficult to identify the source of serial multiple impacts with the current source localization techenology(SLT) because of the overlapping of dispersive wave induced by multiple impacts and the reflaction from the edge of the plate. In this paper, the new method is suggested for source localization. The method is developed based on the SLT with pre-signal processing such as some limitation for the selection of three sensors, the frequency range for TFA and impact time interval. Results from numerical simulation and experiment in isotropic plate structure are presented, which show the capability of the proposed method.

• 전산구조공학
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• 제1권2호
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• pp.83-90
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• 1988

본 연구에서는 평판 구조물의 해석을 위한 개선된 유한요소를 제시하였다. 이 요소는 Mindlin 평판이론에 의하여 수식화되었으며, 'Heterosis'평판요소의 변위장에 비적합변위형을 추가함으로써 유도되었다. 본 연구에서 제시한 평판요소는 요소의 강체운동과 관련된 Zero Eigenvalue만을 갖고 있으므로 Spurious Zero Energy Mode를 보이지 않는다. 대표적인 문제에 대한 수치해석을 해 본 결과 본 연구에서 제시한 평판요소는 우수한 수렴도를 보여 주었으며, 아주 얇은 평판문제에서도 요소의 형상에 관계없이 Shear Locking현상을 극복하였다.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2005년도 동계학술발표대회 논문집
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• pp.564-569
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• 2005

Recently, from the viewpoint of global wanning, natural gas CO2 is considered as a main refrigerant for hot water system. The characteristics of CO2 is not toxic, not flammable, high pressure, and high refrigerating capacity. Also it is widely available as a byproduct of industrial processes. This paper describes the performance analysis program of the swash plate type compressor using CO2 refrigerant. Estimates of the refrigerant flow rate, compression work, discharge temperature and volumetric, compressor efficiencies of the CO2 swash plate type compressor are obtained from the various design parameter such as the inclination angle of the swash plate, discharge hole area and suction hole area.