• Computational Structural Engineering
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• v.5 no.1
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• pp.83-89
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• 1992

A practical method of estimating inelastic deflection of reinforced concrete slab under service load is presented. Based on the elastic results of linear finite element analysis and area of reinforcement, inelastic deflection multiplier(.betha.) is evaluated and desired deflection as a measure of serviceability of the designed slab is obtained. Example for the corner supported slab shows that the results from the proposed method agree well with those from the experiment/and nonlinear finite element analysis. Application of the method to the design of irregular slab is also considered.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2003.03a
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• pp.104-408
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• 2003

케이블 장대 교량의 해석에 있어서 기하적인 비선형만을 고려한 해석이 보편적이었다. 하지만 이 연구에서는 내진 해석시 케이블지지 교량이 비탄성적으로 거동 할 수 있기 때문에, 기하적인 비선형 이외에 재료적인 비선형을 고려할 필요가 있음을 보이고자 한다. 극한 하중 상태를 모사하기 위하여 사하중에 하중계수를 곱하여 하중을 증가시켜 중력방향으로 하중을 가하였고, 지진에 대한 하중 상태를 모사하기 위하여 교축방향의 지진 하중에 대한 등가의 등분포 하중과 이의 0.3배에 해당하는 수직 방향 하중을 동시에 가하였다. 이러한 해석을 통하여 자중의 2배 이상의 하중이 가해지면 거더가 비탄성적으로 거동 할 수 있고, 또한 교축 방향과 수직 방향의 설계지진하중을 고려할 경우 수평방향의 구속이 모두 풀리면 주탑이 비탄성적으로 거동 할 수 있음을 알 수 있다. 따라서 케이블지지 교량의 지진 해석시 특정한 경우에 있어서는 비탄성 거동을 고려해야 할 필요가 있을 것으로 보인다.

• Geophysics and Geophysical Exploration
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• v.10 no.4
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• pp.252-258
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• 2007

We have studied the feasibility of geostatistics approach to enhancing analysis of sparsely obtained seismic data by combining with satellite gravity data. The shallow depth and numerous fishing nets in The Yellow Sea, west of Korea, makes it difficult to do seismic surveys in this area. Therefore, we have attempted to use geostatistics to integrate the seismic data along with gravity data. To evaluate the feasibility of this approach, we have extracted only a few seismic profile data from previous surveys in the Yellow Sea and performed integrated analysis combining with the results from gravity data under the assumption that seismic velocity and density have a high physical correlation. First, we analyzed the correlation between extracted seismic profiles and depths obtained from gravity inversion. Next, we transferred the gravity depth to travel time using non-linear indicator transform and analyze residual values by kriging with varying local means. Finally, the reconstructed time structure map was compared with the original seismic section given in the previous study. Our geostatistical approach demonstrates relatively satisfactory results and especially, in the boundary area where seismic lines are sparse, gives us more in-depth information than previously available.

• Composites Research
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• v.25 no.1
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• pp.1-8
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• 2012

In order to predict the thermoelastic behavior of porous composites, poroelastic parameters are measured by using micromechanics-based finite element models. The expanding deformation caused by pore pressure, and the degradation of homogenized elastic moduli with pores are calculated for the assessment of the poroelastic parameters. Various representative volume elements considering the shape, size, and array pattern of pores are modeled and analyzed by a finite element method. The effects of porosity and material anisotropy, and the distribution of stain energy density are investigated carefully. In addition, the measured poroelastic parameters are verified by predicting the thermo-pore-elastic behavior of carbon/phenolic composites.

• Journal of the Earthquake Engineering Society of Korea
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• v.8 no.1
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• pp.39-58
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• 2004

It is very important that predict the inelastic seismic behavior exactly for seismic performance evaluation of a building in the performance based seismic design. Evaluation method of seismic performance based on the pushover analysis reflected in PBSE was developed by some researchers. For the evaluation of inelastic global and local seismic responses by pushover analysis exactly. lateral load distribution should be adjusted and reflected the dynamic characteristics of structural system and various seismic ground motions. And performance point should be determined based on the evaluation of reasonable deformation capacity of a building more exactly. An effective method based on the improved the adaptive lateral load distribution and the equivalent responses of a multistory building is proposed in this study to efficiently estimate the accurate inelastic seismic responses. The proposed method can be used to evaluate the seismic performance for the global inelastic behavior of a building and to accurately estimate its local inelastic seismic responses. In order to demonstrate the accuracy and validity of this method, inelastic seismic responses estimated by the proposed method are compared with those obtained from other analytical methods.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.38 no.5
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• pp.527-534
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• 2014

Poroelastic analyses of fiber-reinforced composites were performed using image-based computational models. The section image of a porous matrix was analyzed in order to investigate the porosity, number of pores, and distribution of pores. The resolution, location, and size of the section image were considered to quantify the effective elastic modulus, poroelastic parameter, and strain energy density using the image-based computational models. The poroelastic parameter was calculated from the effective elastic modulus and pore pressure-induced strain. In addition, the results of the poroelastic analyses were verified through representative volume elements by simplifying various pore configurations and arrangements.

• Journal of Aerospace System Engineering
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• v.14 no.5
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• pp.1-8
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• 2020

The aeroservoelastic analysis that deals with the interactions of the inertial, elastic, and aerodynamic forces and the influence of the control system have been performed. MSC Nastran was used for the free vibration analysis of the structure model as the pre-analysis. ZAERO was used to calculate the unsteady aerodynamic forces. The unsteady aerodynamic forces were verified by comparing with Doublet Hybrid Method. Karpel's Minimum-State Approximation method was used for approximation of the aerodynamic forces to the Laplace domain in the frequency domain. The aeroservoelastic state-space equation was obtained by combining the aeroelastic equation with the actuator dynamics. The analysis of aeroservoelastic stability concerning the elevator input of the high aspect ratio model was performed. The root-locus method and time-integration method were used for the analysis of aeroservoelastic in frequency and time domain.

• Journal of the KSME
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• v.31 no.3
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• pp.276-292
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• 1991

복합체 구조물을 광탄성 실험법으로 응력해석 하고자 할 때는 반드시 아래의 사항이 연구되어야 한다. (1) 복합체 구조물의 이방성 성질과 상사되는 광탄성 재료가 개발되어야 한다. (2) 광탄성 재료의 기본 물성치($E_L,E_r,G_{LT},V_{LT}$)와 응력 프린지치($f_L,f_r,f_{LT}$) 등이 측정되어야 한다. (3) 복합체 구조물의 응력 해석을 할 수 있는 광탄성 실험의 실험 방법이 개 발되어야 한다. 이론적으로 규명하기 힘들고 역학적으로 논란되고 있거나 인명에 관계되는 기 계나 구조물 등을 이론적으로 해결하였으나 실험적으로 확인하려고 할 때 광탄성 실험법은 확인 실험법으로써 매우 유용한 방법이므로 아래와 같이 요구된다. 광탄성 실험법이 앞에서 나열된 것처럼 파괴 역학의 여러 분야에도 유용하게 이용될 뿐만 아니라 의학 분야에도 매우 유용하게 이용되고 있다.

• Proceedings of the Korean Nuclear Society Conference
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• 1998.05b
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• pp.169-174
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• 1998

두께는 일정하나 너비가 균일하게 변하는 판스프링들로 구성된 너비감소 판형 홀다운 스프링 집합체에 대한 탄성강성도 특성해석을 수행하였다. 국산 경수로 핵연료의 홀다운스프링 집합체와 동일한 설계공간내에 있도록 고안한 여러 종류의 너비감소 판형 홀다운 스프링 집합체 시편에 대한 탄성강성도를 해석적으로 평가하였고 특성시험을 수행하였다 또한 실제 시험 결과들을 잘 예측할 수 있도록 Euler 보 이론과 변형률 에너지법에 근거한 탄성강성도 평가방법을 보정하였다.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 1986.11a
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• pp.47-51
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• 1986

로울러 베어링의 로울러는 길이방향으로 적당하게 Profiling하여 양단부에서 발생하는 응력집중을 줄이고 있다. 로울러와 레이스간의 접촉을 단순한 탄성접촉문제로 해석하는 경우에는 유막의 개념이 없어서 로울러와 레이스 사이의 압력분포와 유막형상을 정확하게 나타내기가 어려우므로 탄성변형과 압력에 따른 윤활유의 점도 변화를 고려한 탄성유체윤활(EHL)해석이 필요하다. 대부분의 해석은 무한장 로울러로 취급하는 것이 보통이며 실제의 로울러에 해당하는 유한한 길이의 선접촉 EHL 해석은 Mostofi & Gohar 및 Kuroda & Arai의 해석 정도이나 각각은 수렴하중이 작거나 로울러의 길이가 아주 짧은 경우에 해당한다. 본 연구에서는 FDM과 Newton-Raphson method를 이용하여 길이가 유한한 실제 크기의 Profiled 로울러에 대한 EHL상태에서의 압력분포와 유막형상을 보다 하중이 온 경우에 대해서 구하고자 한다.