• Proceedings of the KSME Conference
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• 2003.11a
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• pp.1666-1671
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• 2003

Exact dynamic stiffness model for a uniform straight pipeline conveying unsteady fluid is formulated from a set of fully coupled pipe-dynamic equations of motion, in which the fluid pressure and velocity of internal flow as well as the transverse and axial displacements of the pipeline are all treated as dependent variables. The accuracy of the dynamic stiffness model formulated herein is first verified by comparing its solutions with those obtained by the conventional finite element model. The spectral element analysis based on the present dynamic stiffness model is then conducted to investigate the effects of fluid parameters on the dynamics and stability of an example pipeline problem.

• Steel and Composite Structures
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• v.23 no.6
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• pp.737-746
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• 2017

In this paper the influence of aspect ratio, height ratio and material angle on static and free vibration behaviour of orthotropic elliptic paraboloid shells is studied by using a four-node hybrid stress finite element. The formulation of the element is based on Hellinger-Reissner variational principle. The element is developed by combining a hybrid plane stress element and a hybrid plate element. A parametric study is carried out for static and free vibration response of orthotropic elliptic paraboloid shells with respect to displacements, internal forces, fundamental frequencies and mode shapes by varying the aspect and height ratios, and material angle.

• Journal of Biomedical Engineering Research
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• v.25 no.4
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• pp.283-288
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• 2004

The finite element modeling of small female occupant for crash simulation is presented in this paper subsequently to the part I of articulated rigid body model. The limbs and internal components are additionally modeled by joining them to the articulated rigid body model for predicting the crash injuries such as bone fractures and joint dislocations. The behavioral characteristics of each limbs and internal components were validated against available cadaveric test results. Accordingly, the human model proposed in this paper could be utilized for the investigation of impact injury mechanism and further complement the lacking biofidelity of current crash dummy.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.30 no.5 s.248
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• pp.568-575
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• 2006

The present paper provides plastic limit load solutions of axial and circumferential through-wall cracked pipes based on detailed three-dimensional (3-D) finite element (FE) limit analysis using elastic-perfectly-plastic behavior. As a loading condition, axial tension, global bending moment, internal pressure, combined tension and bending and combined internal pressure and bending are considered for circumferential through-wall cracked pipes, while only internal pressure is considered for axial through-wall cracked pipes. Especially, more emphasis is given for through-wall cracked pipes subject to combined loading. Comparisons with existing solutions show a large discrepancy in short through-wall crack (both axial and circumferential) for internal pressure. In the case of combined loading, the FE limit analyses results show thickness effect on limit load solutions. Furthermore, the plastic limit load solution for circumferential through-wall cracked pipes under bending is applied to derive plastic $\eta\;and\;{\gamma}$-factor of testing circumferential through-wall cracked pipes to estimate fracture toughness. Being based on detailed 3-D FE limit analysis, the present solutions are believed to be meaningful fur structural integrity assessment of through-wall cracked pipes.

• Journal of Biomedical Engineering Research
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• v.25 no.4
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• pp.277-282
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• 2004

In order to investigate the small female occupant behavior and accompanying injury mechanisms in vehicular trash event, a finite element model of $5^{th}$ percentile female has been developed. The model consists of articulated rigid body, which represents the morphology of small female body, and internal components with anatomical details. Articulated rigid body model serves as a basic platform for joining the detail internal skeletons and organs, while itself can be used for representing the overall kinematics of small female occupant. The modeling details such as anthropometry and finite element structure as well as validation results for the articulated rigid body model are introduced in this paper. The second part of the modeling, i.e. the internal components with anatomical details of small female are presented in subsequent part II of the paper.

• Computational Structural Engineering
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• v.7 no.2
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• pp.101-109
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• 1994

A degenerated cylindrical shell element for modeling glass fiber reinforced plastic pipes is developed and its performance for static structural analysis under internal uniform pressure is evaluated. The element is a nine node degenerated solid shell element with reduced integration technique, addition of nonconforming displacement modes, and assumed strain method to improve convergence of analysis. Several numerical examples are solved and compared with analytical solutions and other F.E.M programs, The results show that the increment of fiber orientation in the GFRP pipes with reference to the longitudinal axis cause less radial displacements and much stiffness in the pipes. This is reasonable since the internal pressure will primarily cause hoop stresses in the ring and 90-angle ply GFRP ring carry these efficiently in pure tension.

• Journal of Biomedical Engineering Research
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• v.15 no.4
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• pp.413-418
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• 1994

In electrical impedance tomography (EIT), we use boundary current and voltage measurements to provide the information about the cross-sectional distribution of electrical impedance or resistivity One of the major problems in EIT has been the inaccessibility of internal voltage or current data in finding the internal impedance values. We propose a new image reconstruction method using internal current density data measured by NMR. We obtained a two-dimensional current density distribution within a phantom by processing the real and imaginary MR images from a 4.7T NMR machine. We implemented a resistivity image reconstruction algorithm using the finite element method and sensitivity matrix. We presented computer simulation results of the image reconstruction algorithm and furture direction of the research.

• Steel and Composite Structures
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• v.1 no.1
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• pp.131-144
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• 2001

Overpressurization can occur due to the ignition of flammable vapors existing inside aboveground oil storage tanks. Such accidents could happen more frequently than other types of accident. In the tank design, when the internal pressure increases, the sidewall-to-roof joint is expected to fail before failure occurs in the sidewall-to-bottom joint. This design concept is the socalled "frangible roof joint" introduced in API Standard 650. The major failure mode is bifurcation buckling in this case. This paper presents the bifurcation buckling pressures in both joints under internal pressure. Elastic and elastic-plastic axisymmetric shell finite element analysis was performed involving large deformation in the prebuckling state. Results show that API Standard 650 does not evaluate the frangible roof joint design conservatively in small diameter tanks.

• The Journal of Internal Korean Medicine
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• v.30 no.1
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• pp.200-211
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• 2009

There are many reports about correlations between meteorological elements and stroke. In Oriental medicine, it is recognized that the weather affects the human body and diseases, but there are few studies about the correlation between meteorological elements and pattern identification of stroke. 105 stroke patients classified into fire-heat pattern or dampress-phlegm pattern were registered during the study period. We took the measurement of each meteorological element (atmospheric pressure, temperature, humidity, wind speed) according to pattern identification and analyzed pattern identification into two groups according to mean of each meteorological element during the study period. Mean temperature was higher with the heat-fire pattern than with the dampness-phlegm pattern. Heat-fire pattern also had higher frequency when temperature was higher than mean temperature. There was no correlation between atmospheric pressure, relative humidity, or wind speed and pattern identification.

• Korean Journal of Microbiology
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• v.31 no.3
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• pp.208-213
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• 1993

The structural and functional roles of IGS element of T4 td intron in thymidylate synthase activity in vivo were investigated Site-directed mutagenesis was employed to crete mutations of IGS element of T4 td intron, When a U-G pari was changed to a U-C pari in the 5' splice site of P1 stem of td intron, the activity of thymidylate synthase was completely abolished whereas the wild type retained the normal activity of enzyme. When U at 12 position within IGS element was changed to C, the activity of thymidylate synthase was approximately 32% of that of the wild type. Comparison of enzyme activities suggests that IGS element within P1 structure is an essential requirement for splicing of td gene in vivo.