• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2006년 창립20주년기념 정기학술대회 및 국제워크샵
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• pp.201-204
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• 2006

A three-dimensional finite element (FEM) model has been developed to simulate the deformation due to bead on plate welding of curved plates with curvature in the weld direction. By using traditional method such as thermal-elastic-plastic FEM, the weld-induced deformation can be predicted accurately. However, this method is not practical approach to analyze the deformation of large and complex structures such as ship hull structures in view of time and cost. This study is classified from the aspect of equivalent load based on inherent strain near the weld line. Therefore, the residual deformation can be simply computed by elastic analysis. Further more, a practical solution is proposed to consider the contact between the plate and the positioning jig by judging the reaction forces of the jig at calculation step and the effect of the longitudinal curvature is closely considered.

• Composites Research
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• 제15권5호
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• pp.35-43
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• 2002

본 연구는 폭이 변하는 transversely isotropic 판에서 평행한 변에 서로 크기가 다른 면내 축방향 압축력이 작용하며, 경사진면에는 면내 전단력이 작용하는 경우 판의 탄성좌굴거동에 관한 해석적 연구결과이다. 폭이 변하는 등방성판의 좌굴해석을 위해 개발된 기존의 이론적 해를 확장하여 transversely isotropic 재료의 역학적 성질을 고려한 좌굴해석을 할 수 있도록 하였다. 이론식은 power series를 사용하여 유도하였으며, 유한요소해석을 부가적으로 수행하고 그 결과를 이론식을 사용한 해석결과와 비교, 검토하였다.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 1998년도 가을 학술발표회 논문집
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• pp.397-404
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• 1998

A plate on the elastic half-space may generally be analyzed by the finite element method. However, there are some difficulties to obtain the flexibility matrix of the foundation based on the Boussinesq's theory. In this study, an efficient numerical procedure which uses the analysis results of the vertical displacements due to the uniformly distributed loading in a circular area is presented. Some numerical examples represent better results than those of numerical integration technique or subsection method especially in the case of irregular mesh pattern.

• 한국음향학회지
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• 제2권1호
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• pp.48-58
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• 1983

The transient sound radiation from the impact between a steel ball and a thick plate is analyzed theoretically and compared with experiment results. The derivation process itself is difficult to analyze sound radiation characteristics theoretically for a thick plate with some resonances but may be investigated from measured data. During mechanical impacts, arbitrary driving point importance for an elastic system enables to predict by using mechanical importance method. In order to obtain approximate solution for an impact model testing, the surface Helmholtz integral formulation based on the integral expression for pressure in the field in terms of surface pressure and normal velocity is used as a basis. A simple expression is developed for an impulsive response function, which is time dependent velocity potential and pressure for an impact may then be computed by a convolution of exciting force. In estimating of elastic-acoustical correlation problems, mechanical inertance, overall transfer function and radiation resistance obtained by signal processing techniques are used. The usefulness is confirmed by applying these methods prediction of arbitray driving pint inertance, radiated sound pressure and exciting force.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 1997년도 가을 학술발표회 논문집
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• pp.87-94
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• 1997

The circular plate resting on Boussinesq's half-space model under axisymmetric loading is studied by a finite element procedure to evaluate the distribution of contact pressure between plate and elastic half-space. The displacement of half-space due to axisymmetric surface loading can be evaluated by double integration of Boussinesq's solution. On that case the analytical integration can be executed for the radial direction but the analytical integration for the circumferential direction is impossible and the numerical integration should be considered. With the radial integration we can get non-dimensional function. Then the numerical integration for the formula is executed for the circumferential direction and the results are approximated 5th order Polynomials by using the least square method. With these 5th order approximate formula, the flexibility matrix of half-space is constructed as the coefficient matrix of nodal contact pressure by the finite element procedures. Iteration procedures are attempted by using this method to determine the separated region.

• Structural Engineering and Mechanics
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• 제62권4호
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• pp.431-441
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• 2017

In this article, an analytical-numerical approach is presented in order to determine the dynamic response of thin plates resting on multiple elastic point supports with time-varying stiffness. The proposed method is essentially based on transforming a familiar governing partial differential equation into a new solvable system of linear ordinary differential equations. When dealing with time-invariant stiffness, the solution of this system of equations leads to a symmetric matrix, whose eigenvalues determine the natural frequencies of the point-supported plate. Moreover, this method proves to be applicable for any plate configuration with any type of boundary condition. The results, where possible, are verified upon comparison with available values in the literature, and excellent agreement is achieved.

• 한국철도학회논문집
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• 제3권2호
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• pp.84-91
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• 2000

The general concept of reinforced roadbed in the high-speed railway is to cope with the soft ground for the bearing capacity and settlement of foundation soil. The cyclic plate load tests were performed to determine the behavior of reinforced ground with multiple layers of geogrid underlying by soft soil. With the test results, the bearing capacity ratio, elastic rebound ratio, subgrade modulus and the strain of geogrids under loading were investigated. Based on these plate load tests, laboratory model tests under cyclic loading were conducted to estimate the effect of geogrid reinforcement in particular for the high-speed rail roadbed. The permanent settlement and the behavior of earth pressure in reinforced roadbed subjected to a combination of static and dynamic loading are presented.

• Smart Structures and Systems
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• 제23권4호
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• pp.387-392
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• 2019

This research deals with the vibration analysis of embedded smart concrete plate reinforced by zinc oxide (ZnO). The effective material properties of structure are considered based on mixture rule. The elastic medium is simulated by orthotropic visco-Pasternak medium. The motion equations are derived applying Sinusoidal shear deformation theory (SSDT). The differential quadrature (DQ) method is applied for calculating frequency of structure. The effects of different parameters such as volume percent of ZnO, boundary conditions and geometrical parameters on the frequency of system are shown. The results are compared with other published works in the literature. Results indicate that the ZnO have an important role in frequency of structure.

• Smart Structures and Systems
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• 제23권5호
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• pp.429-447
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• 2019

The present study analyzed free vibration of the three-layered micro annular/circular plate which its core and face sheets are made of saturated porous materials and FG-CNTRCs, respectively. The structure is subjected to magneto-electric fields and magneto-electro-mechanical pre loads. Mechanical properties of the porous core and also FG-CNTRC face sheets are varied through the thickness direction. Using dynamic Hamilton's principle, the motion equations based on MCS and FSD theories are derived and solved via GDQ as an efficient numerical method. Effect of different parameters such as pores distributions, porosity coefficient, pores compressibility, CNTs distribution, elastic foundation, multi-physical pre loads, small scale parameter and aspect ratio of the plate are investigated. The findings of this study can be useful for designing smart structures such as sensor and actuator.

• Smart Structures and Systems
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• 제30권4호
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• pp.371-383
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• 2022

A novel impact localization method is presented based on impact induced elastic waves in sensorized composite structure subjected to temperature fluctuations. In real practices, environmental and operational conditions influence the acquired signals and consequently make the feature (particularly Time of Arrival (TOA)) extraction process, complicated and troublesome. To overcome this complication, a robust TOA estimation method is proposed based on the times in which the absolute amplitude of the signal reaches to a specific amplitude value. The presented method requires prior knowledge about the normalized wave velocity in different directions of propagation. To this aim, a finite element model of the plate was built in ABAQUS/CAE. The impact location is then highlighted by calculating an error value at different points of the structure. The efficiency of the developed impact localization technique is experimentally evaluated by dropping steel balls with different energies on a carbon fiber composite plate with different temperatures. It is demonstrated that the developed technique is able to localize impacts with different energies even in the presence of noise and temperature fluctuations.