• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2005.10a
• /
• pp.49-54
• /
• 2005

This paper describes the result of structure analysis and load test of body structure. The purpose of the analysis and test is to evaluate an safety which body structure shall be considered fully sufficient rigidity so as to satisfy proper system function under maximum load and operating condition. Material of body structure applied an aluminum alloy. Body structure consist of side frame, under frame, roof frame, end frame. Both FEM analysis and load test are based on 'Performance Test Standard for Electrical Multiple Unit, noticed by Ministry of Construction & Transportation, in 2000' and reference code is JIS E 7105. The test results have been very safety and stable fer design load conditions.

• Wind and Structures
• /
• v.10 no.4
• /
• pp.347-366
• /
• 2007

Guyed masts subjected to turbulent winds exhibit complex vibrations featuring many vibration modes, each of which contributes to various structural responses in differing degrees. This dynamic behaviour is further complicated by nonlinear guy cable properties. While previous studies have indicated that conventional frequency domain methods can reliably reproduce load effects within the mast, the system linearization required to perform such an analysis makes it difficult to relate these results directly to corresponding guy forces. As a result, the estimation of peak load effects arising jointly from the structural action of the mast and guys, such as leg loads produced as a result of guy reactions and mast bending moments, is uncertain. A numerical study was therefore undertaken to study peak load effects in a 295 m tall guyed mast acted on by simulated turbulent wind. Responses calculated explicitly from nonlinear time domain finite element analyses were compared with approximate methods in the frequency domain for estimating peak values of selected responses, including guy tension, mast axial loads and mast leg loads. It was found that these peak dynamic load effects could be accurately estimated from frequency domain analysis results by employing simple, slightly conservative assumptions regarding the correlation of related effects.

• International Journal of Precision Engineering and Manufacturing
• /
• v.9 no.3
• /
• pp.59-63
• /
• 2008

A static load analysis of twin-screw kneaders is required not only for the dynamic analysis, but also because it is the basis of the stiffness and strength calculations that are essential for the design of bearings. In this paper, the static loads of twin-screw kneaders are analyzed, and a mathematical model of the force and torque moments is presented using a numerical integration method based on differential geometry theory. The calculations of the force and torque moments of the twin-screw kneader are given. The results show that the $M_x$ and $M_y$ components of the fluid resistance torque of the rotors change periodically in each rotation cycle, but the $M_z$ component remains constant. The axis forces $F_z$ in the female and male rotors are also constant. The static load calculated by the proposed method tends to be conservative compared to traditional methods. The proposed method not only meets the static load analysis requirements for twin-screw kneaders, but can also be used as a static load analysis method for screw pumps and screw compressors.

• Magazine of the Korean Society of Agricultural Engineers
• /
• v.45 no.2
• /
• pp.78-85
• /
• 2003

This study aims to investigate the effect of partially distributed loads on the static behavior of parabolic arches by using the elastic-plastic finite element model. For this purpose, the vertical, the radial, and the anti-symmetric load cases are considered, and the ratio of loading range and arch span is increased from 20% to 100%. Also, the elastic-visco-plastic analysis has been carried out to estimate the elapse time to reach the stable state of arches when the ultimate load obtained by the finite element analysis is applied. It is noted that the ultimate load carrying capacities of parabolic arches are 6.929 tf/$m^2$ for the radial load case, and 8.057 tf/$m^2$ for the vertical load case. On the other hand, the ultimate load is drastically reduced as 2.659 tf/$m^2$ for the anti-symmetric load case. It is also shown that the maximum ultimate load occurs at the full ranging distributed load, however, the minimum ultimate loads of the radial and vortical load cases are obtained by 2.336 tf/$m^2$, 2.256 tf/$m^2$, respectively, when the partially distributed load is applied at the 40% range of full arch span.

• Journal of Korean Association for Spatial Structures
• /
• v.15 no.3
• /
• pp.43-49
• /
• 2015

A single-layerd steel lattice roof, which has 50m span, was constructed. In order to figure out the realistic buckling load level, the structural analysis of this roof structure was performed especially by local snow load. Due to the characteristics of application of snow load, the load combinations of snow should be considered not only global area but also local part so that the critical buckling load could be observed as easy as possible. Geometrical imperfection was simulated to consider inaccurate shape of structure. And then nonlinear analysis were performed. Finally, this paper could investigate that the local snow load with geometrical imperfection decreased the level of buckling load significantly.

• Proceedings of the KIEE Conference
• /
• 1999.07c
• /
• pp.1478-1480
• /
• 1999

The accurate analysis of power system requires detailed load model. There are two basic approaches in modeling the load characteristics. One is to directly measure the voltage and frequency sensitivity of the load P and Q at substations and feeders. The other is to build up a composite load model from each load component. Each of these methods has advantages and disadvantages. This paper presents load composition for KEPCO's power system to develop load models by the component-based load modeling.

• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
• /
• 2003.02a
• /
• pp.174-177
• /
• 2003

Cooling load from the top plate to L$N_2$ surface, including wall conduction, gas conduction, radiation, and current leads, is investigated in a closed cooling system for HTS transformer. In general methods of load calculation, individual load is estimated separately, but they are actually coupled each other because of natural convection of nitrogen vapor. Using heat transfer analysis, we calculate cooling load with taking into account the effect of natural convection. Cooling load is under- estimated approximately 2 ％ when the natural convection is ignored. If the operating current is high, there will be a wide difference between actual cooling load and cooling load by individual calculation. Cooling load decreases with increasing number of radiation shield. With production, construction, and cooling load, three radiation shields are proper to 1 MVA HTS transformer.

• 유체기계공업학회:학술대회논문집
• /
• 2004.12a
• /
• pp.385-389
• /
• 2004

Test facilities for the wind turbine performance monitoring and mechanical load measurements are installed in Vestas 100 kW wind turbine in Wollyong test site, Jeju island. The monitoring system consists of Garrad-Hassan T-MON system, telemetry system for blade load measurement, various sensors such as anemometer, wind vane, strain gauge, power meter, and etc. The experimental procedure for the measurement of wind turbine loads, such as edgewise(lead-lag) bending moment, flapwise bending moment, and tower base bending moment, has been established. Strain gauges are on-site calibrated against load cell prior to monitoring the wind turbine loads. Using the established monitoring system, the wind turbine is remotely monitored. From the measured load data, the load analysis has been performed to obtain the load power spectral density and the fatigue load spectra of the wind turbine.

• Journal of Institute of Control, Robotics and Systems
• /
• v.14 no.2
• /
• pp.111-117
• /
• 2008

This paper presents a new continuation-based quasi-steady-state(CQSS) time-domain simulation algorithm incorporating a multiplicative aggregated load model for power systems. The authors' previous paper introduced a CQSS algorithm, which has the robust convergent characteristic near the singularity point due to the application of a continuation method. The previous CQSS algorithm implemented the load restoration in power systems using the exponent-based load recovery model that is derived from the additive dynamic load model. However, the reformulated exponent-based model causes the inappropriate variation of short-term load characteristics when switching actions occur, during time-domain simulation. This paper depicts how to incorporate a multiplicative load restoration model, which does not have the problem of deforming short-term load characteristics, into the time simulation algorithm, and shows an illustrative example with a 39-bus test system.

• Journal of Korean Association for Spatial Structures
• /
• v.23 no.1
• /
• pp.69-76
• /
• 2023

A timber lattice roof, which has around 30m span, was constructed. In order to figure out the realistic buckling load level, the structural analysis of this roof structure was performed especially by stiffness of connection with various asymmetric snow load. Due to the characteristics of application of snow load, the load combinations of snow should be considered not only global area but also local part so that the critical buckling load could be observed as easy as possible. Geometrical imperfection was simulated to consider inaccurate shape of structure. And then nonlinear analysis were performed. Finally, this paper could investigate that the asymmetric snow load with the lower level stiffness of connection decreased the level of buckling load significantly.