• Journal of Astronomy and Space Sciences
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• v.16 no.2
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• pp.177-190
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• 1999

An absorbed heat-flux method for ground simulation of on-orbit thermal environment of satellite is addressed in this paper. For satellite ground test, high vacuum and extremely low temperature of deep space are achieved by space simulation chamber, while spatial environmental heating is simulated by employing the absorbed heat-flux method. The methodology is explained in detail with test requirement and setup implemented on a satellite. Developed heat-load control system is presented with an adjusted PID-control logic and the system schematic realized is shown. A practical and successful application of the heat simulation method to KOMPSAT(Korea Multi-purpose Satellite)thermal environmental test is demonstrated, finally.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.5 no.7
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• pp.1308-1313
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• 2001

This paper presents methods of parameter measurement and starting characteristics of a 3 phase induction motor. The motor parameters measured by DC test, blocked rotor test, and no load test are used as the input data for computer simulation. Starting characteristics are analyzed through computer simulation using measured parameters, and the simulation results are compared with the experimental results obtained by using strain gauge attached on the motor shaft. It is conformed that the experimental results are very similar to those of the simulation.

• Proceedings of the KIEE Conference
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• 2001.07b
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• pp.849-851
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• 2001

This paper presents experimental method of parameter measurement and starting characteristics of 3 phase induction motor. Equivalent circuit parameters measured by DC test, the blocked rotor test, and no load test were used as the input data for computer simulation. Starting characteristics, such as starting current and torque were analyzed through computer simulation by Matlab, and the simulation results were compared with experiment using strain gauge attached on motor shaft. We conform that experimental results are very similar to that of simulation.

• Journal of Electrical Engineering and Technology
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• v.7 no.6
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• pp.845-851
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• 2012

Power system loads have a significant impact on a system. Although it is difficult to precisely describe loads in a mathematical model, accurately modeling them is important for a system analysis. The traditional load modeling method is based on the load components of a bus. Recently, the load modeling method based on measurements from a system has been introduced and developed by researchers. The two major components of a load modeling problem are determining the mathematical model for the target system and estimating the parameters of the determined model. We use the composite load model, which has both static and dynamic load characteristics. The ZIP model and the induction motor model are used for the static and dynamic load models, respectively. In this work, we propose the measurement-based parameter estimation method for the composite load model. The test system and related measurements are obtained using transient security assessment tool(TSAT) simulation program and PSS/E. The parameter estimation is then verified using these measurements. Cases are tested and verified using the sample system and its related measurements.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.63 no.7
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• pp.956-961
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• 2014

Due to the increasing needs of anti-fall device for elderly, it is required to develop the test rigs for fall simulation. The femoral bone model consists of silicone and steel is used as an effective device to simulate falls. In this work, we propose five different femoral bone models and analyse them by using a commercial FEA tool. It has been shown that two kinds of simplified models exhibit the simulated side falls with an error range of ~1% in the impact load of femoral neck compared with full model. Especially, the upper tissue model is found to provide us with the best efficient test environment, attributable to its simple structure.

• Journal of Sensor Science and Technology
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• v.31 no.6
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• pp.411-417
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• 2022

In this paper, we propose a sensor with a C-shaped load cell to detect force change when a person sitting on the chair in an electrical transport-convenience vehicle is pushing ground by both heels. The load cell built in the vehicle is mechanically deformed by the vertical force owing to the human weight and the horizontal force by ground-pushing feet. The deformation rate of the load cell and its distribution are simulated using finite element analysis. In the simulation, the applied loads are preset in the range of 10 kg - 100 kg with a step size of 10 kg, and the ground-pushing force by feet is increased to 40 N with a step size of 5 N with respect to each applied load level. The resistance change of the load cell was observed to be linear in simulation as well as in measurement. the maximum difference between simulation and measurement was 0.89 % when the strain gauge constant was 2.243. The constant has a large influence on the difference. The proposed sensor was fabricated by connecting an instrument amplifier and a microcontroller to a load cell and used to detect the force by ground-pushing feet. To detect foot driving, the reference signal was set to 130% of the load, and the duration of the sensor output signal exceeding the reference signal was set to 0.6 s. In a test of a vehicle built with the proposed sensor, the footpushing force by the worker could be successfully detected even when the worker was working.

• Advances in aircraft and spacecraft science
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• v.2 no.3
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• pp.345-365
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• 2015

This paper focuses on the design, fabrication, testing and analysis of a novel load-bearing element with energy dissipation capability. A single element comprises two von-Mises trusses (VMTs), which are sandwiched between two plates and connected to dashpots that stroke as the VMTs cycle between stable equilibrium states. The elements can be assembled in-plane to form a large plate-like structure or stacked with different properties in each layer for improved load-adaptability. Also introduced in the elements are pre-loaded springs (PLSs) that provide high initial stiffness and allow the element to carry a static load even when the VMTs cannot under harmonic disturbance input. Simulations of the system behavior using the Simscape environment show good overall correlation with test data. Good energy dissipation capability is observed over a frequency range from 0.1 Hz to 2 Hz. The test and simulation results show that a two layer prototype, having one soft VMT layer and one stiff VMT layer, can provide good energy dissipation over a decade of variation in harmonic load amplitude, while retaining the ability to carry static load due to the PLSs. The paper discusses how system design parameter changes affect the static load capability and the hysteresis behavior.

• Transactions of Materials Processing
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• v.19 no.7
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• pp.435-440
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• 2010

The creep life of 9Cr1MoVNb steel, in terms of Larson-Miller parameter(LMP), was evaluated by small punch(SP) creep simulation and verified by uniaxial creep test. By employing the elastoplastic FEM(finite element method), the small punch creep behaviors associated with various friction coefficients were simulated to identify a real friction phenomena. The friction coefficient, ${\mu}$=0.7, determined by comparing deflection history was used in the small punch creep simulation to find the equivalent stresses with which the relationship between punch load and uniaxial creep stress was found. The creep life was then predicted by the LMP, which was the relationship among the rupture time, temperature, and stress. Finally, the LMP calculated by SP-creep simulation was compared with that had computed by the uniaxial creep test and fairly matched LMPs were found.

• Computers and Concrete
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• v.33 no.3
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• pp.265-273
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• 2024

Predicting fracture properties requires an understanding of structural failure behaviour in relation to specimen type, dimension, and notch length. Facture properties are evaluated using various testing methods, wedge splitting test being one of them. The wedge splitting test was numerically modelled three dimensionally using the finite element method on self compacting concrete specimens with varied specimen and notch depths in the current work. The load - Crack mouth opening displacement curves and the angle of rotation with respect to notch opening till failure are used to assess the fracture properties. Furthermore, based on the simulation results, failure curve was built to forecast the fracture behaviour of self-compacting concrete. The fracture failure curve revealed that the failure was quasi-brittle in character, conforming to non-linear elastic properties for all specimen depth and notch depth combinations.

• Transactions of the Korean Society of Automotive Engineers
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• v.16 no.5
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• pp.77-83
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• 2008

Semi-active cabin air suspension system improves driver's comfort by controlling the damping characteristics in accordance with driving situation. For the driver's comfort evaluation, test procedure has the two methodologies which are filed test and lab test. A field test method has a drawback. It requires a lot of time and money on repetitive test, due to the sensitivity of field test. On the other hand, the test with six axes simulation table at laboratory can obtain the repeatability of test, better than the field test method. In this paper, the procedures of ride performance test and control logic tuning with the table are presented. Drive files of the table can be represented with the almost same input condition as field test data. According to the result from the comparative test using six axes simulation table between passive and semi-active system by making ECU logic tuning, the RMS acceleration of semi-active cabin air suspension system was reduced by 29.6% compared with passive system.