• Transactions of Materials Processing
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• v.15 no.2 s.83
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• pp.153-157
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• 2006

In this study, the die design and die series on the surface residual stress of cold drawn eutectoid steel wire have been investigated. Test pieces were fabricated using die series with different mean and final reduction ratios. Surface residual stresses in the axial direction were measured by X-ray diffraction, Bruker's 2-dimensional GADDS system. The results were compared with stress profiles that were calculated by 3D and 2D finite element simulations, ABAQUS 6.4 program in finite element analysis(FEA). By means of the FEA method, optimal die shape considering delta-parameter were induced and applied in order to determine die sequence designs. Balance of the drawing stresses was also introduced to optimize die sequence.

• Structural Engineering and Mechanics
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• v.55 no.3
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• pp.473-494
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• 2015

A graded harmonic finite element formulation based on three-dimensional elasticity theory is developed for the structural analysis of 2D functionally graded axisymmetric structures. The mechanical properties of the axisymmetric solid structures composed of two different metals and ceramics are assumed to vary in radial and axial directions according to power law variations as a function of the volume fractions of the constituents. The material properties of the graded element are calculated at the integration points. Effects of material distribution profile on the static deformation, natural frequency and dynamic response analyses of particular axisymmetric solid structures are investigated by changing the power law exponents. It is observed that the displacements, stresses and natural frequencies are severely affected by the variation of axial and radial power law exponents. Good accuracy is obtained with fewer elements in the present study since Fourier series expansion eliminates the need of finite element mesh in circumferential direction and continuous material property distribution within the elements improves accuracy without refining the mesh size in axial and radial directions.

• Proceedings of the KSME Conference
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• 2000.04a
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• pp.345-350
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• 2000

Adaptive finite element analysis, which its solution error meets with the user defined allowable error, is recently used far improving reliability of finite element analysis results. This adaptive analysis is composed of two procedures; one is the error estimation of an analysis result and another is the reconstruction of finite elements. In the rp-method, an element size is controlled by relocating of nodal positions(r-method) and the order of an element shape function is determined by the hierarchical polynomial(p-method) corresponding to the element solution error. In order to show the effectiveness and accuracy of the suggested rp-method, various numerical examples were analyzed and these analysis results were examined by comparing with those obtained by the existed methods. As a result of this study, following conclusions are obtained. (1) rp-method is more accurate and effective than the r- and p-method. (2) The solution convergency of the rp-method is controlled by means of the iterative calculation numbers of the r- and p- method each other.

• Journal of Korean Tunnelling and Underground Space Association
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• v.21 no.2
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• pp.211-225
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• 2019

Recently, earthquakes have occurred throughout the entire region of Korea and seismic analysis studies have been actively conducted in various fields. SSI analyses studies considering ground have been carried out consistently. However, few comparative analyses have been performed on the dynamic behavior of buildings according to numerical analysis method in the case of the previous dynamic analyses considering grounds. Therefore, in this study, the dynamic analyses were performed on a high-rise building by using both a finite element program MIDAS GTS NX and a finite difference program FLAC 2D. The results were compared and analyzed each other. As a result, both the maximum compressive and tensile bending stresses of above ground and below ground part were estimated to be a little larger by MIDAS GTS NX than by FLAC 2D. However, the maximum horizontal displacement value, the horizontal displacement distribution, and the position of weak part were turned out to be similar in both analysis programs. Therefore, it can be concluded that there is no difference in using either a finite element program or a finite difference program for the convenience of a user for a dynamic analysis.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1994.10a
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• pp.843-846
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• 1994

The bucking and postbuckling behavior of composite laminated long cylinders under lateral pressure are investigated by the nonlinear finite element method. A long cylinder of 3-D shell problem is modelled as 2-D plane strain problem for analysis. And for the finite element analysis, eight nodes quadratic element is utilized. Arc-length method is adopted for the iteration and load-increment along postbuckling equilibrium path. The composite laminated cylinders in study are composed of cross-plied uniaxially reinforced shells. As a prsult, buckling load and postbuckling behavior are discussed.

• Journal of the Korean Geotechnical Society
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• v.23 no.1
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• pp.67-76
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• 2007

Flat DMT penetration was analyzed using a finite element model based on a large strain formulation. The ABAQUS/Explicit, a commercial finite element method, was used to study the flat DMT penetration in soils. Then, because the very large mesh distortion occurred due to the penetration of flat DMT, the adaptive meshing technique was utilized to maintain a high quality mesh configuration. The undrained shear strength obtained from the flat DMT is estimated using only the horizontal stress index ($K_{D}$) and so it became necessary to examine using the analysis results obtained from the penetration of the flat DMT. Analysis results show that in normally consolidated region of $K_{D}=2$, the results obtained from the correlations proposed by Marchetti show good agreement with those estimated from the finite element method. The present analysis also shows that in overconsolidated region of $K_{D}>2$, the results obtained from the relationships proposed by Kamei and Iwasaki show good agreement with those provided by the penetration analysis.

• Journal of Advanced Marine Engineering and Technology
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• v.28 no.8
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• pp.1279-1285
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• 2004

This paper presents the characteristic simulation of PM-type magnetic circuit breaker with the 2D finite element magnetic field solution including non-linearity of the material and an eddy current. Change of dynamic characteristic of the actuator is quantified from the finite element analysis. The results obtained from a commercial finite element analysis software are compared with those calculated from the developed finite element analysis software. A new modified model to decrease the eddy current is proposed. The characteristics of the two models are compared.

• Journal of Advanced Marine Engineering and Technology
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• v.31 no.2
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• pp.190-196
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• 2007

This paper presents the 3D finite element analysis of the Contact-less Power Supply(CPS) with linear servo motor. The primary, secondary self and leakage inductances of the contact-less power supply and the capacitances of a resonant circuit are calculated by the finite element analysis using current source. The voltage source is used to do accurate analysis of the characteristics of the contact-less power supply. The CPS with the linear servo motor is proposed. The characteristics analysis of the contact-less power supply considering the linear servo motor is done.

• Computers and Concrete
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• v.16 no.5
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• pp.759-774
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• 2015

This study simulates the flexural behavior of ultra-high-performance fiber-reinforced concrete (UHPFRC) beams reinforced with steel and glass fiber-reinforced polymer (GFRP) rebars. For this, micromechanics-based modeling was first carried out on the basis of single fiber pullout models considering inclination angle. Two different tension-softening curves (TSCs) with the assumptions of 2-dimensional (2-D) and 3-dimensional (3-D) random fiber orientations were obtained from the micromechanics-based modeling, and linear elastic compressive and tensile models before the occurrence of cracks were obtained from the mechanical tests and rule of mixture. Finite element analysis incorporating smeared crack model was used due to the multiple cracking behaviors of structural UHPFRC beams, and the characteristic length of two times the element width (or two times the average crack spacing at the peak load) was suggested as a result of parametric study. Analytical results showed that the assumption of 2-D random fiber orientation is appropriate to a non-reinforced UHPFRC beam, whereas the assumption of 3-D random fiber orientation is suitable for UHPFRC beams reinforced with steel and GFRP rebars due to disorder of fiber alignment from the internal reinforcements. The micromechanics-based finite element analysis also well predicted the serviceability deflections of UHPFRC beams with GFRP rebars and hybrid reinforcements.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.26 no.7
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• pp.39-44
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• 2012

This paper deals with the characteristic analysis of small power brushless DC (BLDC) motor considering the rotor magnet overhang flux. In the driving characteristics analysis using 2D FEA (Finite Element Analysis), the rotor magnet overhang effect can't be considered and it should be neglected. To consider rotor magnet overhang effect, 3D FEA should be required. But 3D FEA requires very long calculation time even though the high specification computer is used. In this paper, the 3D electromagnetic model of BLDC motor is approximated as the 2D electromagnetic model considering overhang effect. In this paper, the concept of overhang coefficient is applied, and the coefficient according to load torque variance is deduced.