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

• Aerospace Engineering and Technology
• /
• v.1 no.2
• /
• pp.11-18
• /
• 2002

The structural load analysis of 50m class airship was performed. The airship maneuver condition for analysis was defined. Aerodynamic, inertia and buoyance models were built. Control surface motion to make defined maneuver condition were calculated. Load factors, load, shear and bending moment envelops were developed for full airship and tailwing. Gondola design loads were developed.

• Journal of the KSME
• /
• v.54 no.7
• /
• pp.40-45
• /
• 2014

풍력발전시스템은 육상용에서 해상용으로 개발되며 대형화하고 있는 추세이다. 풍력발전시스템이 해상용 등으로 대형화되면서 유지, 보수에 높은 비용이 소요되고 이에 따라 신뢰성을 확보하기 위한 요구가 더 커지고 있다. 증속기의 경우 고장 빈도도 낮지 않고, 고장 발생 시 심각도가 높아 신뢰성이 가장 높게 요구된다. 최근 증속기의 신뢰성을 확보하기 위한 연구 개발에서 수명에 가장 영항을 크게 미치는 조건으로 적용하중 영향에 대한 비토크 하중(non-torque load)과 유성기어열의 설계 인자로 취급되는 하중 분할(load sharing), 치면 하중 분포(face-load distribution) 그리고 이를 필수적으로 입증하고자 요구되는 시험/평가 기술에 대하여 소개하고자 한다.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.10 no.4
• /
• pp.175-184
• /
• 2006

Two methods of the nonlinear static pushover analysis have been presented for the performance-based seismic design and evaluation of MDOF continuous bridges. Guidelines for buildings presented in FEMA-273 applying the Displacement Coefficient Method (DCM) and in ATC applying the Capacity Spectrum Method(CSM) have been modified for MDOF bridges. Two methods are compared with the time- history analysis. The lateral load distribution pattern for seismic loads has been examined in the static pushover analysis. The force-based fiber frame finite element has been implemented in the modeling of reinforced concrete piers.

• Journal of Korean Tunnelling and Underground Space Association
• /
• v.6 no.1
• /
• pp.41-50
• /
• 2004

The numerical investigation for the effects of blasting-induced vibration on adjacent dam and pore water pressure fluctuation was conducted through solid-water coupled analysis under dynamic loading. The stability of dam was examined by peak particle velocity of core. Pore water pressure distributions were calculated by steady state flow analysis using coupled analysis on ground water and blasting-induced vibration. The influence of pore water pressure and the effective stress distribution in the ground were also investigated. Furthermore, effective stress alteration was examined by applying Finn & Byrne Model to monitor the generation and dissipation of pore water pressure.

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.12 no.5
• /
• pp.323-329
• /
• 2002

This paper presents the application of the technique of differential transformation to the post-buckling problem of non-uniform cantilever column subjected to a combined load. Numerical calculations are carried out and compared with previously published results to validate the results of the present method. The results obtained by this method agree very well with those reported in the previous works. The results obtained by the present method are presented for both various non-uniform columns and loads.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.33 no.2
• /
• pp.39-45
• /
• 2005

The aim of this research is to predict the thickness and loading noise of the round-tip shaped Hartzell propeller currently used in the general aviation aircraft. Before implementing the noise analysis, the pressure distribution on the propeller was obtained by using the free wake panel method and unsteady Bernoulli's equation. The noise signal at observer position can be obtained by using the FW-H equation. The noise prediction results for the propeller indicates that the thickness noise has s symmetric directivity pattern with respect to the tip path plane, while the noise due to loading shows higher noise directivity toward downstream than the upstream direction from the rotor plane. The loading noise is dominant rather than the thickness noise in normal operating condition.

• Proceedings of the KSR Conference
• /
• 2003.10b
• /
• pp.85-91
• /
• 2003

본 연구에서는 원과 선분을 이용하여 복잡한 형상의 입자를 표현할 수 있는 2차원 개별요소법(DEM) 알고리즘에 3종류(균등분포, 정규분포, 대수정규분포)의 입도분포를 구현할 수 있도록 하였다. 개발된 프로그램을 이용하여 다양한 반지름을 갖는 원형요소를 구현하고 도상자갈을 원하는 입도분포로 모델링할 수 있었다. 그리고 우선적으로 균등분포에 대하여 변위제어 하중 재하 방식에 의하여 도상으로부터 노반으로 전달되는 응력을 파악하였다.

• Journal of Korean Society of Steel Construction
• /
• v.10 no.3 s.36
• /
• pp.393-406
• /
• 1998

In this study buckling behavior of orthotropic plate with a longitudinal stiffener under in-plane linearly distributed loads is investigated. All edges of plate are assumed to be simply supported and the stiffener is considered as a beam element. For the equation of buckling analysis Rayleigh-Ritz method is employed. The upper limit of the critical stress at various location of stiffener is determined by using Lagrangian multiplier method. Buckling analysis is performed for the various position of stiffener and for the various width ratios between plate and stiffener. The parametric study shows that, when four edges of plate are simply supported, the most effective position for a longitudinal stiffener is at the location of which the upper limit of the stress is the maximum.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.30 no.4
• /
• pp.38-43
• /
• 2002

A study on the test, design and fabrication of wind tunnel model for measurement of air load distribution on wing surfaces is presented. 447 pressure taps are installed normal to the wing surfaces, and measured by PSI-8400 system using total 8 ESPs modules installed in the model. The test was performed at 50 m/sec constant speed in the low speed wind tunnel of Agency for Defense Development. Tests were carried out to determine effects of angle of attack, angle of sideslip and flap and stores for the load distribution of wing. The test results in this paper can be applied to the design optimization of structure and validation of computational fluid dynamics.