• Computers and Concrete
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• v.19 no.3
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• pp.263-273
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• 2017

In this paper, a finite element model (FEM) in ATENA-3D software was constructed to investigate the behavior of circular ultra high performance concrete (UHPC) filled steel tube stub columns (UHPC-FSTCs) under concentric loading on concrete core. The "CC3DNonLinCementitious2User" material type for concrete in ATENA-3D software with some modifications of material laws, was adopted to model for UHPC core with consideration the confinement effect. The experimental results obtained from Schneider (2006) were then employed to verify the accuracy of FEM. Extensive parametric analysis was also conducted to examine the influence of concrete compressive strength, steel tube thickness and steel yield strength on the compressive behavior of short circular UHPC-FSTCs. It can be observed that the columns with thicker steel tube show better strength and ductility, the sudden drop of load after initial peak load can be prevented. Based on the regression analysis of the results from parametric study, simplified formulae for predicting ultimate loads and strains were proposed and verified by comparing with previous analytical models, design codes and experimental results.

• Journal of the Korean Society of Visualization
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• v.9 no.3
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• pp.16-23
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• 2011

Experiment and numerical investigation are performed on swirling water flow in a vertical circular tube. This kind of flow is used in heat exchangers, combustion chambers, thermal power plants, and other mechanical equipment to move slurries or to convey materials. However, limited information on swirling flow in vertical circular tubes is available. In the current paper, the three-dimensional particle image velocimetry(PIV) technique is employed to compare the measured velocity profiles of water along the vertical circular tube with those of non-swirl flow. In addition, computational fluid dynamics(CFD) code was applied to calculation of the flow velocities with swirl.

• Smart Structures and Systems
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• v.15 no.5
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• pp.1345-1362
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• 2015

The present paper deals with the free vibration analysis of the functionally graded solid and annular circular plates with two functionally graded piezoelectric layers at top and bottom subjected to an electric field. Classical plate theory (CPT) is used for description of the all deformation components based on a symmetric distribution. All the mechanical and electrical properties except Poisson's ratio can vary continuously along the thickness direction of the plate. The properties of plate core can vary from metal at bottom to ceramic at top. The effect of non homogeneous index of functionally graded and functionally graded piezoelectric sections can be considered on the results of the system. $1^{st}$ and $2^{nd}$ modes of natural frequencies of the system have been evaluated for both solid and annular circular plates, individually.

• Journal of Information Processing Systems
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• v.12 no.1
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• pp.83-99
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• 2016

The latest research on the image-based fingerprint matching approaches indicates that they are less complex than the minutiae-based approaches when it comes to dealing with low quality images. Most of the approaches in the literature are not robust to fingerprint rotation and translation. In this paper, we develop a robust fingerprint matching system by extracting the circular region of interest (ROI) of a radius of 50 pixels centered at the core point. Maximizing their orientation correlation aligns two fingerprints that are to be matched. The modified Euclidean distance computed between the extracted orientation features of the sample and query images is used for matching. Extensive experiments were conducted over four benchmark fingerprint datasets of FVC2002 and two other proprietary databases of RFVC 2002 and the AITDB. The experimental results show the superiority of our proposed method over the well-known image-based approaches in the literature.

• Proceedings of the Korean Magnestics Society Conference
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• 2002.12a
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• pp.210-211
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• 2002

The magnetic anisotropy of amorphous wires plays a decisive role in the giant magnetoimpedance(GMI) behavior. The magnetoelastic anisotropy caused by internal stress, that are frozen in during the fabrication process, results in an axial easy axis in the core region and in a circular easy axis in the shell region [1]. It leads to a simple domain structure consisting of circular domains in the shell and axial domains in the core. For a more realistic domain structure, it has been suggested that the helical anisotropy exists due to an internal helical stress [2]. (omitted)

• Steel and Composite Structures
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• v.23 no.2
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• pp.229-238
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• 2017

This paper presents a combined numerical and theoretical study on the composite action between steel and concrete of circular steel tube confined concrete (STCC) stub columns under axial compressive loading with a full theoretical elasto-plastic model and finite element (FE) model in comparison with experimental results. Based on continuum mechanics, the elasto-plastic model for STCC stub columns was established and the analysis was realized by a FORTRAN program and the three dimensional FE model was developed using ABAQUS. The steel ratio of the circular STCC columns were defined in range of 0.5% to 2% to analyze the composite action between steel tube and concrete, and make a further study on the advantages of the circular STCC columns. By comparing the results using the elasto-plastic methods with the parametric analysis result of FE model, the appropriate friction coefficient between the steel tube and core concrete was defined as 0.4 to 0.6. Based on ultimate balance theory, the formula of ultimate load capacity applying to the circular STCC stub columns was developed.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.55 no.8
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• pp.397-400
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• 2006

An optimized iron core structure of stimulating coil are presented in order to control the induced electric field distribution using the Continuum Design Sensitivity Analysis (CDSA) combined with a commercially available generalized finite element code (OPERA). The results show that a Figure-Of-Eight (FOE) coil as well as a circular coil with the proposed iron core structure can increase induced electric field intensity by more than two times and make better field localization, compared with those of existing stimulation coil with a air core. After considering manufacturing constraints, a practical iron core structure based on the proposed optimized one is proposed and its performance is analyzed.

• Transactions of the Korean Society of Mechanical Engineers
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• v.10 no.6
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• pp.823-829
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• 1986

The Large-scale structure of the circular jet in the transition region, which influences the subsequent flow in the turbulent region, was studied experimentally. Measuring equipments are composed of the two channel hot-wire anemometer, the computer controlled two-directional traverse mechanism, the data acquisition system, and FFT-analyzer. The circular jet has 50mm diameter. The mean velocity distribution, the velocity fluctuation, the auto 'cross correlations and the power spectra were acquired at moderate Reynolds number of 10$^{4}$. And the VITA method was used to measure the convection velocity of Large-scale eddy. The phase of u'is in advance of that of v'in all regions. .over bar. $R_{u}$(.tau.=0) is approximately zero in the potential core region, but a small regular deviation is observed. At a position in the mixing layer region the convection velocity is different along the part of the eddy, and in this experiment the convection velocity of the inner region is larger than the outer region. The averge convection velocity of the eddy along y/D=0 was approximately constant in the transition region.D=0 was approximately constant in the transition region.

• The Journal of Advanced Prosthodontics
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• v.5 no.4
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• pp.434-439
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• 2013

PURPOSE. The aim of the present study was to evaluate the effects of posts with different morphologies on stress distribution in an endodontically treated mandibular premolar by using finite element models (FEMs). MATERIALS AND METHODS. A mandibular premolar was modeled using the ANSYS software program. Two models were created to represent circular and oval fiber posts in this tooth model. An oblique force of 300 N was applied at an angle of $45^{\circ}$ to the occlusal plane and oriented toward the buccal side. von Mises stress was measured in three regions each for oval and circular fiber posts. RESULTS. FEM analysis showed that the von Mises stress of the circular fiber post (426.81 MPa) was greater than that of the oval fiber post (346.34 MPa). The maximum distribution of von Mises stress was in the luting agent in both groups. Additionally, von Mises stresses accumulated in the coronal third of root dentin, close to the post space in both groups. CONCLUSION. Oval fiber posts are preferable to circular fiber posts in oval-shaped canals given the stress distribution at the postdentin interface.

• Journal of Power System Engineering
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• v.10 no.4
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• pp.119-126
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• 2006

Gerotor hydraulic motor is widely used in hydraulic systems due to its low speed, high torque output and compactness in rotational direct driving of a heavy weight. Gerotor is a Planar mechanism consisted of a pair of rotor and circular teeth of stator assembly which forms a closed space, so called a chamber. The motion of rotor relative to the circular tooth is produced by the pressure difference of hydraulic operating fluid between the adjacent chamber. As all active contact points of rotor and circular teeth are subjected to very high sliding friction, a reduction in the performance of the gerotor hydraulic motor can not be avoided. Therefore, the core design parameters of gerotor profile used in hydraulic motors is to minimize a friction force by high contact stresses. The analytical design method of gerotor profile, based on envelope of a family of curves, is proposed. In this study, the influence of the tip clearances on three critical contact points between rotor and circular teeth of stator assembly has been explored by experimental data in this paper. At the same time a improvement method to reduce the friction force is proposed and the tip clearances on three critical points for getting an optimum gerotor profile are also analyzed.