• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.40 no.8
• /
• pp.670-677
• /
• 2012

In this paper, mechanical property of biomorphic C/SiC composite was calculated by unit cell analysis. The microstructural arrangements of carbonized pine and radiata pine which were impregnated with silicon, were idealized as square and hexagonal arrays. Unit cell was then defined and equivalent elastic constants were calculated. A single and double unit cell structures were considered. The effect of void distribution was also studied by monte carlo simulation.

• Journal of the Society of Naval Architects of Korea
• /
• v.56 no.3
• /
• pp.242-250
• /
• 2019

The speed and power performance of a ship is not only a guarantee issue between the ship owner and the ship-yard, but also is related with the Energy Efficiency Design Index (EEDI) regulation. Recently, International Organization for Standardization (ISO) published the procedure of the measurement and assessment for ship speed and power at sea trial. The results of speed and power performance measured in actual sea condition must inevitably include various uncertainty factors. In this study, the influence for systematic error of shaft power measurement system was examined using the Monte Carlo simulation. It is found that the expanded uncertainty of speed and power performance is approximately ${\pm}1.2%$ at the 95% confidence level(k=2) and most of the uncertainty factor is attributed to shaft torque measurement system.

• Journal of Korean Association for Spatial Structures
• /
• v.10 no.1
• /
• pp.75-84
• /
• 2010

According to the available study and experimental data about the long term behavior of CFT(Concrete Filled Tube) columns, the creep and of concrete in CFT columns are smaller than those of RC columns because of the confinement effect of outer steel columns. In this study, the uncertainties associated with assumed values for concrete properties such as strength, creep coefficients, and service load have been considered and analyzed for the prediction of time-dependent column shortening of CFT column. The CFT column shortening analysis using Monte Carlo method is proposed and an of a 37 story tall building with CFT columns is studied for illustration. According to the results obtained by the probability analysis with multi parameters, the effect of variation coefficient for 3 parameters is investigated considering confidence interval.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.35 no.10
• /
• pp.989-996
• /
• 2011

An understanding of the concentrated solar flux is critical for the analysis and design of solar-energy-utilization systems. The current work focuses on the development of an algorithm that uses the Monte Carlo ray-tracing method with excellent flexibility and expandability; this method considers both solar limb darkening and the surface slope error of reflectors, thereby analyzing the solar flux. A comparison of the modeling results with measurements at the solar furnace in Korea Institute of Energy Research (KIER) show good agreement within a measurement uncertainty of 10%. The model evaluates the concentration performance of the KIER solar furnace with a tracking accuracy of 2 mrad and a maximum attainable concentration ratio of 4400 sun. Flux variations according to measurement position and flux distributions depending on acceptance angles provide detailed information for the design of chemical reactors or secondary concentrators.

• Proceedings of the KSEEG Conference
• /
• 2003.04a
• /
• pp.165-168
• /
• 2003

최근 사면의 안정해석분야에서 자주 사용되고 있는 확률론적 해석 방법은 현장에서 획득 되는 자료들의 분산이 심하고 충분한 양의 자료가 획득되지 못할 경우 자료 내에 포함되는 불확실성과 가변성을 효과적으로 다룰 수 있는 방법 중의 하나로 인식되어 왔다. 그러나 대개 확률론적 해석 방법에서 이용되는 몬테카를로 시뮬레이션기법(Monte Carlo simulation method)은 파괴확률을 산정하기 위하여 수 많은 반복적인 계산과정이 요구되며 따라서 많은 시간과 노력이 필요하다는 단점을 가지고 있다. (중략)

• The Journal of Engineering Geology
• /
• v.21 no.3
• /
• pp.247-257
• /
• 2011

In this study the infinite slope model, one of the physical landslide models has been suggested to evaluate the susceptibility of the landslide. However, applying the infinite slope model in regional study area can be difficult or impossible because of the difficulties in obtaining and processing of large spatial data sets. With limited site investigation data, uncertainties were inevitably involved with. Therefore, the probabilistic analysis method such as Monte Carlo simulation and the GIS based infinite slope stability model have been used to evaluate the probability of failure. The proposed approach has been applied to practical example. The study area in Boeun area been selected since the area has been experienced tremendous amount of landslide occurrence. The geometric characteristics of the slope and the mechanical properties of soils like to friction angle and cohesion were obtained. In addition, coefficient of variation (COV) values in the uncertain parameters were varied from 10% to 30% in order to evaluate the effect of the uncertainty. The analysis results showed that the probabilistic analysis method can reduce the effect of uncertainty involved in input parameters.

• Journal of the Computational Structural Engineering Institute of Korea
• /
• v.21 no.3
• /
• pp.211-216
• /
• 2008

Recently a lot of researches have been conducted on the progressive collapse of structures which is the total collapse of structures initiated by localized damage. Most of the previous studies on the field of progressive collapse have followed deterministic approach without considering uncertainty involved in design variables, which results in unknown reliability of the analysis results. In this study the sensitivity analyses are carried out with design variables such as yield strength, live load, damping ratio, and elastic modulus on the vertical deflection of the joint from which a column is suddenly removed. The Monte Calro simulation, tornado diagram method, and the first order second moment method(FOSM) are applied for the sensitivity study. According to the nonlinear static analysis results, the vertical deflection is most affected by the variation of yield strength of beams. The nonlinear dynamic analyses show that the behaviour of model structures is highly sensitive to variation of the yield strength of beams and the structural damping ratio.

• Computational Structural Engineering
• /
• v.8 no.1
• /
• pp.127-136
• /
• 1995

In this paper the stochastic FE analysis considering the material and geometrical property of the plate structure is performed by the weighted integral method. To consider the stochasity of the material and geometrical property, the stochastic field is assumed respectively. The mean value of the stochastic field is 0 and the value of variance is assumed as 0.1. The characteristics of the assumed stochastic field is represented by auto-correlation function. This auto-correlation function is used in evaluating the response variability of the plate structure. In this study a new auto-correlation function is derived to concern the uncertainty of the plate thickness. The newly derived auto-correlation function is a function of auto-correlation function and coefficient of variation of the assumed stochastic field. The two results, obtained by proposed Weighted Integral method and Monte Carlo Simulation method, are coincided with each other and these results are almost equal to the theoretical result that is derived in this study. In the case of considering the variability of plate thickness, the obtained result is well coincide with those of Lawrence and Monte Carlo simulation.

• Journal of Navigation and Port Research
• /
• v.34 no.6
• /
• pp.435-440
• /
• 2010

A numerical model, which can compute deformation of rubble mound structures composed with various size materials, was proposed. In the numerical model, wave field into the mound structures was computed by CADMAS-SURF and the deformations of mound structures were computed by DEM. Interaction between wave field and sectional deformation of structure was considered and to present the variation of behaviors caused by various properties of materials, computation was carried out with random coefficients by Monte Carlo simulation method for contact stiffness and friction angle. The experiments were carried out with rubbles and glass balls with radius of 2.9cm, 2.6cm and 1.5cm. And the deformation characteristics of rubble mounds composed with various size materials were clarified. Furthermore the validity and the applicability of the model were discussed by comparing with the experimental results.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.28 no.5
• /
• pp.580-586
• /
• 2004

The ray effects of finite volume method (FVM) or discrete ordinate method (DOM) are known to show a non-physical oscillation in solution of radiative heat transfer on a boundary. This wiggling behavior is caused by the finite discretization of the continuous control angle. This article proposes a combined procedure of the Monte-Carlo and finite-volume method (CMCFVM) for solving radiative heat transfer in absorbing, emitting, and an-isotropically scattering medium with an isolated boundary heat source. To tackle the problem, which is especially pronounced in a medium with an isolated heat source, the CMCFVM is suggested here and successfully applied to a two-dimensional circular geometry.