• Proceedings of the Computational Structural Engineering Institute Conference
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• 2000.10a
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• pp.190-197
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• 2000

A moment-curvature relationship to simulate the behavior of reinforced concrete beam under cyclic loading is introduced. Unlike previous moment-curvature models and the layered section approach, the proposed model takes into consideration the bond-slip effect by using monotonic moment-curvature relationship constructed on the basis of the bond-slip relation and corresponding equilibrium equation at each nodal point. In addition, the use of curved unloading and reloading branches inferred from the stress-strain relation of steel gives more exact numerical result. The advantages of the proposed model, comparing to layered section approach, may be on the reduction in calculation time and memory space in case of its application to large structures. The modification of the moment-curvature relation to reflect the fixed-end rotation and pinching effect is also introduced. Finally, correlation studies between analytical results and experimental studies are conducted to establish the validity of the proposed model.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2002.04a
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• pp.3-11
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• 2002

A moment-curvature relationship to simulate the behavior of reinforced concrete (RC) columns under cyclic loading is introduced. Unlike previous moment-curvature models and the layered section approach, the unposed model takes into account the bond-slip effect by using a monotonic moment-curvature relationship constructed on the basis of the bond-slip relation and corresponding equilibrium equation at each nodal point. In addition, the use of curved unloading and reloading branches inferred from the stress-strain relation of steel gives more exact numerical result. The pinching enact caused by axial force is considered with an assumption that the absorbing energy corresponding to any deformation level maintains constant regardless of the magnitude of applied axial force. The advantages of the proposed model, comparing tn layered section approach, may be on the reduction in calculation time and memory space in case of its application to large structures.. Finally, correlation studies between analytical results and experimental studies are conducted to establish the validity of the proposed mood.

• Proceedings of the KIEE Conference
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• 1995.07a
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• pp.350-352
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• 1995

The starting characteristics of single phase induction motor(SPIM) is described by control of phase and voltage. Auxiliary winding voltage is controlled by DC amplifier and phase is integrator. These processes enable comparison of torque with slip in each voltage and phase angle variations. Simulation and experimentation results of the motor's torque-slip characteristics using the controlled auxiliary winding voltage and phase angle arc shown and discussed. As a results, starting time is fast and main winding current is small when auxiliary winding voltage is low than rating voltage and starting characteristics is good in phase angle $90^{\circ}$.

• Journal of applied mathematics & informatics
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• v.41 no.3
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• pp.487-510
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• 2023

We propose a mathematical model which describes the frictional contact between a piezoelectric body and an electrically conductive foundation. The behavior of the material is described with a linearly electro-viscoelastic constitutive law with long term memory. The mechanical process is dynamic and the electrical conductivity coefficient depends on the total slip rate, the friction is modeled with Tresca's law which the friction bound depends on the total slip rate with taking into account the electrical conductivity of the foundation both. The main results of this paper concern the existence and uniqueness of the weak solution of the model; the proof is based on results for second order evolution variational inequalities with a time-dependent hemivariational inequality in Banach spaces.

• Journal of the Korean Society of Costume
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• v.55 no.6 s.96
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• pp.109-124
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• 2005

The object of this study was to identify the production technique and immediate constituent of lingerie by examining the materials and the sewing techniques. Various papers are referenced for theoretical study and the elements and techniques of lingerie are analyzed based on photographical materials. From the late 20C century to the present time was the research time period. This paper concludes as follows: 1 Decorative method: Lace, Ribbons, piping, elastic bands were some of the decorative materials attached to the garments by zigzag stitch. 2. Flat pattern making: Lingerie patterns were drafted in smaller size than the patterns of outer garments. Bias cut would be applied for the noll-stretchable fabrics. 3. Draping: Bias grain would be applied for the non-stretch fabric. When draping stretch fabrics, follow the grain line of the fabrics and pull the fabric so that it could fit onto the body. 4. Production technique: Straight stitch would be applied for non-stretch fabrics. Zigzag stitch would be applied for stretch fabrics.

• Journal of Biosystems Engineering
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• v.24 no.2
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• pp.99-106
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• 1999

This study was conducted to provide a direction for improving the performance of triangular-type belt clutch. The power transmission characteristics and the wear of belt were investigated for two types of pulley set theoretically and experimentally. The results of research were summarized as follows: 1) Based on the theoretical analysis for the life time of belt, the wear of belt could be reduced by increasing the sizes of driving V-pulley and tension pulley, and by decreasing the tension on V-belt. 2) The pulley set # 2 could transmit more power than the pulley set # 1 could at the same slop rate. While the slip rate was 2.36% on the pulley set # 2 at the maximum power transmission, the slip rate on the pulley set # 1 was increased up to 12.2% at the same condition. 3) From the 16 hours' fatigue test, the wear of belt used n the pulley set # 1 was observed severer than that in the pulley set#2. Also, it was found that the tensile strength of belt used in the pulley set # 2 was greater than that of belt used in the pulley set # 1.

• Journal of the Korean Society of Safety
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• v.27 no.5
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• pp.1-8
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• 2012

The purpose of this study were to evaluate the dynamic characteristics of the portable slipmeters with respect to actual slipping and to compare their output with those of force platform. The selected slipmeters were commonly used devices for slipperiness measurement in situ floors. Their output quantity represented force (BOT-3000), loss of energy(British pendulum striker) and angle of inclination(English XL). The validity of these devices was studied with respect to actual slipping using a force platform. The precision of these devices was also evaluated with force platform. Based on dynamics of human subject behavior when slipping during normal walking, the all devices tested in this study showed poor performances: low built up ratio, low normal pressure, and long contact time prior to slip. Nevertheless, their results reasonably correlated with those calculated from the ground reaction forces generated by the operation of the selected slipmeters on the force platform although the absolute values of COF from these three devices could be quite different. Also the results showed good repeatability under the some test conditions.

• Earthquakes and Structures
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• v.12 no.5
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• pp.515-527
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• 2017

Recently, Friction dampers become popular due to the desirable performance in the energy dissipation of lateral loads. A lot of research which has been conducted on these dampers results in developing friction dampers with low sensitivity to the number of cycles and temperature increases. Friction dampers impose high residual drifts to the buildings because of low post-yield stiffness of the damper which results from increasing lateral displacement and period of buildings. This issue can be more critical under strong aftershocks which results in increasing of structural damages. In this paper, in addition to the assessment of aftershock on steel buildings equipped with friction dampers, methods for controlling residual drifts and decreasing the costs of retrofitting are investigated. Utilizing rigid connections as a lateral dual system and activating lateral stiffness of gravity columns by adding elastic braces are as an example of effective methods investigated in this research. The results of nonlinear time history analyses on the low to medium rise steel frames equipped with friction dampers illustrate a rise in residual drifts as the result of aftershocks. In addition, the results show that different slip loads of friction damper can affect the residual drifts. Furthermore, elastic stories in comparison to rigid connections can reduce residual drifts of buildings in an effective fashion, when most slip loads of friction dampers are considered.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.3 no.3
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• pp.651-659
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• 1999

This Paper Proposes new speed and electromagnetic torque control of an induction motor, which is robust against time varying parameters. The control is based on adaptive vector control with serial block adaptive algorithm. Motor parameters used to estimates slip frequency and electromagnetic torque. Parameters mismatch in the control system detrimentally affects slip frequency estimation and torque response. In order to compensate lot degradation of the responses, an adaptive identifier for the magnetizing inductance and the secondary time constant is introduced. adaptive vector control system consisted of two subsystems, a vector control system realized on synchronous frame and a parameter identification system on stationary frame. the effectiveness of the proposed method was verified by some digital simulations.

• Bulletin of the Korean Chemical Society
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• v.17 no.4
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• pp.365-373
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• 1996

Time profile of the transient grating signal induced by a nanosecond pulsed laser excitation of methyl red is investigated in alcohols and toluene at several solvent temperatures. The signal decays biexponentially with well-separated time constants; the faster decay is identified as due to thermal diffusion of the solvents and the slower one as mainly due to translational diffusion of the solute. The measured translational diffusion constants of methyl red in toluene are close to a hydrodynamic prediction with a slip boundary condition while those in alcohols are larger by 30% and increase slightly with the size of alcohols. We compare the results with modified hydrodynamic models.