• 한국농공학회논문집
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• 제46권2호
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• pp.67-75
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• 2004

This study aims to investigate the dynamic behaviour of a parabolic arch with initial deflection by using the elasto-plastic finite element model where the von-Mises yield criteria have been adopted. The initial deflection of arch was assumed by the high order polynomial of ${\omega}_i$ = ${\omega}_o$${(1-{(2x/L)}^m)}^n$) and the sinusoidal profile of ${\omega}_i$ = ${\omega}_o$$\sin$(n$\pi$x/L). Several numerical examples were tested considering symmetric initial deflection modes when the maximum initial deflection of an arch is fixed as L/500, L/1000, L/2000 or L/5000. The effects of polynomials order on the dynamic behavior of arch were not conspicuous. The most unfavorite dynamic response occurs when the maximum initial deflection varies from L/1000 to L/4000 if the initial deflection mode is represented by high order polynomials.

• 한국자동차공학회논문집
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• 제2권4호
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• pp.50-58
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• 1994

To examine the residual stress field resulting from stamping process for the lower control arm of a car, the explicit finite element analysis is performed for the stamping process by way of the ABAQUS Explicit. The residual stress is obtained in terms of the Von Mises stress and other parameters such as equivalent plastic strain, the change of blank thickness, the final configuration of the blank and the spring back effect are also considered. Moreover, discussed is the convergence of the explicit FEM versus the punch sped and the element discretization

• 한국자동차공학회논문집
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• 제12권5호
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• pp.198-204
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• 2004

Dynamic fracture is investigated in plate applied by impacting bar. Numerical simulations of the experiments are made by using a finite element method(FEM) code, LS-DYNA. The eroding surface-to-surface contact allows between impacting bar and impacted plate. The occurrence of hourglass deformations in an analysis can invalidate results and hourglass energy is minimized to obtain the good accuracy of result. Total, internal and kinetic energies, von Mises plastic stress and X,Y,Z velocities of impacting bar are analyzed in this study.

• Journal of Magnetics
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• 제18권2호
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• pp.207-211
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• 2013

In a coaxial magnetic gear, bridges connecting separate pole pieces are useful for fabrication and also improve mechanical reliability. However, they have a negative influence on electromagnetic performance parameters such as transmission torque and iron loss. This paper investigates the effect of stationary pole pieces connected by bridges on the electromechanical characteristics. The bridge type and thickness are the main parameters influencing the performance of a coaxial magnetic gear. The inner, center, and outer bridge types each show the best performance in terms of different characteristics. However, for any bridge type, an increase in the bridge thickness reduces the overall electromagnetic performance, except for the torque ripple, and improves the overall mechanical performance, including the deformation, von Mises stress, and natural frequency of the stationary part.

• 한국신뢰성학회:학술대회논문집
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• 한국신뢰성학회 2000년도 춘계학술대회 발표논문집
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• pp.213-222
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• 2000

In present study, a stochastic model is developed for the low cycle fatigue life prediction and reliability assessment of 316L stainless steel under variable multiaxial loading. In the proposed model, fatigue phenomenon is considered as a Markov process, and damage vector and reliability are defined on every plane. Any low cycle fatigue damage evaluating method can be included in the proposed model. The model enables calculation of statistical reliability and crack initiation direction under variable multiaxial loading, which are generally not available. In present study, a critical plane method proposed by Kandil et al., maximum tensile strain range, and von Mises equivalent strain range are used to calculate fatigue damage. When the critical plane method is chosen, the effect of multiple critical planes is also included in the proposed model. Maximum tensile strain and von Mises strain methods are used for the demonstration of the generality of the proposed model. The material properties and the stochastic model parameters are obtained from uniaxial tests only. The stochastic model made of the parameters obtained from the uniaxial tests is applied to the life prediction and reliability assessment of 316L stainless steel under variable multiaxial loading. The predicted results show good accordance with experimental results.

• 항공우주시스템공학회지
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• 제2권2호
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• pp.28-34
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• 2008

This paper describes the performance characteristics of flow and structure in the post-chamber and nozzle. Using the computational fluid dynamics (CFD) technique, the stress and compressible flow fields in the downstream of the post chamber and nozzle were numerically calculated. Besides, the stress characteristics at the wall of post-chamber and nozzle were investigated under different thickness (2mm, 5mm and 10mm) of the nozzle wall. The stress pattern demonstrates that the strength of nozzle wall having 10mm is safer than that of 5mm or 2mm according to von Mises stress irrespective to the pressure field

• Journal of the Korean Data and Information Science Society
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• 제17권1호
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• pp.259-268
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• 2006

For Type-II censored sample, we propose three modified entropy estimators based on the Vasieck's estimator, van Es' estimator, and Correa's estimator. We also propose the goodness-of-fit tests of the Weibull distribution based on the modified entropy estimators. We simulate the mean squared errors (MSE) of the proposed entropy estimators and the powers of the proposed tests. We also compare the proposed tests with the modified Kolmogorov-Smirnov and Cramer-von-Mises tests which were proposed by Kang et al. (2003).

• Structural Engineering and Mechanics
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• 제62권4호
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• pp.487-496
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• 2017

The focus of this study were to investigate patterns between wall pressures and stresses with grain moisture of soybean and rice varieties widespread cultivated in Turkey in order to determine needed designing parameters for structure analysis in silos at filling and discharge. In this study, the wall pressures and stresses were evaluated as a function of moisture contents in the range of 8-14% and 10-14% d.b. The pressures and von Mises stresses affected as significant by the change of grain moisture content. The main cause of pressure and stress drops is changed in bulk density. Therefore is extremely important bulk density and moisture content of the product at the structural design of the silos. 4 mm wall thickness, were determined to be safe for von Mises stresses in both soybean and rice silos is smaller than 188000 kPa.

• 한국공작기계학회논문집
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• 제17권2호
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• pp.23-29
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• 2008

This study analyzes the rolled circular rod strip with radius of loom and length of 350cm by using finite element analysis. The material strength and its durability of the rolled strip can be predicted through this study. As the penetration tolerance by contact decreases, the contact rigidity of strip increases. As the contact rigidity becomes the highest at the elapsed time of 1.2 second, the contact stress becomes the lowest. On the contrary, von-Mises stress becomes highest at this time. The total deformation on strip increases from the upper part of strip at the position near to rotating roll to the lower part of strip at the position near to fixing roll.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2010년도 학술발표회
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• pp.1179-1183
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• 2010

본 연구에서는 하천유역에 대한 호우의 대표 이동방향을 결정하였다. 대상유역으로는 내성천 유역을 고려하였으며, 101개의 호우사상을 선정하여 각각의 호우사상별로 방향적 특성을 분석하였다. von Mises 분포의 주방향을 이용하여 모든 호우사상의 대표 이동방향을 결정하고, 이를 이용하여 내성천 유역에 대한 호우 대표 이동방향을 결정하였다. 아울러 호우 발생특성별(장마, 태풍, 대류성 강우)로 호우의 방향적 특성을 분류하여 각각의 특성이 구분될 수 있도록 하였다. 적용 결과, 태풍에 의한 호우의 이동방향은 기존 연구결과와 유사하게 주로 북동 방향으로 진행되었으며, 장마와 대류성 강우에 의한 호우가 대표방향 결정에 가장 큰 영향력을 갖는 것으로 나타났다. 아울러 대상유역에 대한 호우의 대표 이동방향은 mode의 특성이 뚜렷하게 한 방향으로 나타나며, 내성천 유역의 경우 대표 호우 이동방향은 59.45도로 결정되었다. 이러한 결과는 한반도에 발생하는 강우의 특성과도 잘 부합하는 것으로 판단된다.