• Structural Engineering and Mechanics
• /
• v.70 no.1
• /
• pp.13-31
• /
• 2019

A nonlinear finite element model (FEM) using ATENA-3D software to simulate the axially compressive behavior of circular steel tube confined concrete (CSTCC) columns infilled with ultra high performance concrete (UHPC) was presented in this paper. Some modifications to the material type "CC3DNonlinCementitious2User" of UHPC without and with the incorporation of steel fibers (UHPFRC) in compression and tension were adopted in FEM. The predictions of utimate strength and axial load versus axial strain curves obtained from FEM were in a good agreement with the test results of eighteen tested columns. Based on the results of FEM, the load distribution on the steel tube and the concrete core was derived for each modeled column. Furthermore, the effect of bonding between the steel tube and the concrete core was clarified by the change of friction coefficient in the material type "CC3DInterface" in FEM. The numerical results revealed that the increase in the friction coefficient leads to a greater contribution from the steel tube, a decrease in the ultimate load and an increase in the magnitude of the loss of load capacity. By comparing the results of FEM with experimental results, the appropriate friction coefficient between the steel tube and the concrete core was defined as 0.3 to 0.6. In addition to the numerical evaluation, eighteen analytical models for confined concrete in the literature were used to predict the peak confined strength to assess their suitability. To cope with CSTCC stub and intermediate columns, the equations for estimating the lateral confining stress and the equations for considering the slenderness in the selected models were proposed. It was found that all selected models except for EC2 (2004) gave a very good prediction. Among them, the model of Bing et al. (2001) was the best predictor.

• Proceedings of the KIEE Conference
• /
• 1998.07a
• /
• pp.134-136
• /
• 1998

When a MCCB Instant trip spring which is adjusted to notrip at -20% of each current from $5{\times}In$ to $10{\times}In$ and trip +20% of those is designed, we should know attraction force between Fixed Magnet and Armature. So we first made some samples, do experiments of weight, and simulated the modelling by 3D Maxwell S/W. With values of experiment and simulated values, we do design instant trip springs and repeat the above process. Finally we set up the Process of designing Instant spring. With it, we can save time and R&D cost.

• Journal of the Korean Geosynthetics Society
• /
• v.15 no.4
• /
• pp.25-32
• /
• 2016

The two-dimensional (2D) analysis is widely used in geotechnical engineering for slope stability analysis assuming a plane-strain condition. It is implicitly assumed that the slip surface is infinitely wide, and thus three-dimensional (3D) end effects are negligible because of the infinite width of the slide mass. The majority of work on this subject suggests that the 2D factor of safety is conservative (i.e. lower than the 'true' 3D factor of safety). Recently, the 3D finite element method (FEM) became more attractive due to the progress of computational tools including the computer hardware and software. This paper presents the numerical analyses on rotational mode and translational mode slopes using the 2D and 3D FEM as well as 2D limit equilibrium methods (LEM). The results of the parametric study on the slope stability due to mesh size, dilatency angle, boundary conditions, stress history and model dimensions change are analysed. The analysis showed that the factor of safety in 3D analysis is always higher than that in the 2D analysis and the discrepancy of the slope width in W direction on the factor of safety is ignored if the roller type of W direction conditions is applied.

• Journal of the Korean Crystal Growth and Crystal Technology
• /
• v.28 no.5
• /
• pp.185-190
• /
• 2018

The Tonpilz transducer was implemented using the structural module of COMSOL which is a FEM simulation tool. In order to compare the sound pressure characteristics of the transducer with the simulated results, the spacial distribution of the sound pressure level (SPL) was simulated by the acoustic module of COMSOL and then compared with the SPL distribution measured by a microphone. As a result, the resonance frequency and the peak in SPL for the simulation were predicted to be 28 kHz and 163.5 dB, respectively. And the resonance frequency and the peak in SPL for the actual transducer were measured to be 28.84 kHz and 137.8 dB, respectively. It is also confirmed that the simulated SPL distribution and the actually measured one are formed in a similar pattern.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2006.11a
• /
• pp.3-6
• /
• 2006

In this study, 3D Design and the Structural Analysis using FEM are conducted for developing the Release Devices. On these bases the prototype devices are made and the reliability has been improved through many environmental tests.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2007.08a
• /
• pp.517-519
• /
• 2007

We report our study on the implementation of Q tensor approach into three-dimensional finite element method (FEM) numerical solver. The comparative simulation results demonstrated the possibility of a different director configuration in between Q tensor method and vector method. The comparative study confirmed that Q Tensor implementation is more appropriate for OCB analysis than the vector method.

• The Transactions of the Korean Institute of Electrical Engineers B
• /
• v.52 no.10
• /
• pp.501-506
• /
• 2003

A Superconducting Rotary Machine (SRM) is characterized by an air-cored machine with its rotor iron and stator iron teeth removed. For this reason, the SRM is featured by 3D magnetic flux distribution, which decreases in the direction of axis. Therefore, 3D magnetic field analysis method is required to know about characteristic of magnetic field distribution of SRM. In this paper, 3D flux distribution of SRM is calculated by analytical method. The magnetic field distribution of the field coils is calculated by Biot-Savart equation. The magnetic core is represented by magnetic surface polarities. This paper describes the combined use of above methods for the total field computation, and compares results of analytical method and 3D FEM(Finite Element Method).

• Journal of Electrical Engineering and Technology
• /
• v.7 no.4
• /
• pp.564-569
• /
• 2012

This paper proposes a hybrid-excited linear synchronous motor (LSM) that has potential applications in a magnetically levitated vehicle. The levitation and thrust force characteristics of the LSM are investigated by means of three-dimensional (3-D) numerical electromagnetic FEM calculations and experimental verification. Compared to a conventional LSM with electromagnets, a hybrid-excited LSM can improve levitation force/weight ratios, and reduce the power consumption of the vehicle. Because the two-dimensional (2-D) FE analysis model describes only the center section of the physical device, it cannot express the complex behavior of leakage flux, which this study is able to predicts along with levitation and thrust force characteristics by 3-D FEM calculations. A static force tester for a hybrid-excited LSM has been manufactured and tested in order to verify these predictions. The experimental results confirm the validity of the 3-D FEM calculation scheme for the description of a hybrid-excited LSM.

• Proceedings of the KSR Conference
• /
• 2008.11b
• /
• pp.310-315
• /
• 2008

Authors design a rotary-type small-scaled linear induction motor(LIM) and a performance test machine before manufacturing a real-scaled LIM for a railway transit. The designed LIM is a single-sided, short primary type and its primary has 4 poles. The rated power is 10(kW). In order to analyze characteristics of the LIM, authors use a mixed 2D-3D FEM analysis. 3-D FEM analysis is used for calculating a distribution of eddy-current on the semi-caped AL-sheet of the secondary reaction. Authors calculate a correction factor of conductivity and an equivalent conductivity on the secondary AL-sheet using a normalized eddy-current. The equivalent conductivity which is calculated in this way includes a transverse edge-effect of the LIM. Authors apply the equivalent conductivity on the secondary AL-sheet of 2D-FEM model and get performance characteristics of the LIM. Basic characteristics such as thrust and normal force, input current, efficiency and power factor of the LIM have been analyzed with the variation of frequency and speed. In order to apply an air-gap control system, the variation of the basic characteristics have been analyzed with the air-gap length variation of the LIM. Finally, authors introduce an operation mode using the air-gap control system and conduct a research on feasibility of the system.

• Journal of Korea Society of Industrial Information Systems
• /
• v.26 no.1
• /
• pp.41-54
• /
• 2021

There is a difficulty in improving the working environment and technological advancement due to power supply through cables in the application of linear motors of robots and transfer systems applied in the existing manufacturing industry. We have studied the shape of the high-frequency coil for contactless power transmission system and characteristics of power conversion system, based on the magnetic field analysis of 2D and 3D, using the FEM-based physical analysis program.