• The Journal of Internal Korean Medicine
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• v.11 no.1
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• pp.77-91
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• 1990

This study was carried out to investigate the effect of Jasoeumja extract on the contractile force of the isolated guinea pig trachea smooth muscle and elucidate its mechanism. The results were obtained as follows: 1. The isolated trachea smooth muscle was suspended in the Organ bath with oxygenated Kreb's Henseleit bicarbonate buffer solution at $37^{\circ}C$, and the developed tension by the drug was recorded with Isometric transducer (Nacro F-60). The resting tension was approximately 0.5g. 2. The trachea smooth muscle of the isolated guinea pig was significantly relaxed by the administration of Jasoeumja extract. 3. The contractile response of the trachea smooth muscle of the isolated guinea pig to histamine $10^{-4}M$ was significantly inhibited by Jasoeumja extract. 4. The contractile response of the trachea smooth muscle of the isolated guinea pig to acetylcholine $10^{-4}M$ was considerably inhibited by Jasoeumja extract. 5. The contractile response of the trachea smooth muscle of the isolated guinea pig to 5-hydroxytryptamine $10^{-4}M$ was considerably inhibited by Jasoeumja extract.

• The Journal of Internal Korean Medicine
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• v.11 no.2
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• pp.68-79
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• 1990

This study was carried out to investigate the effect of Heapyoyangjintang and Haepyoejintang extract on the contractile force of the isolated guinea pig trachea smooth muscle and elucidate its mechanism. The results were obtained as follows : 1. The isolated trachea smooth muscle was suspended in the organ bath with oxygenated kreb's Henseleit bicarbonate buffer solution at $37^{\circ}C$, and the developed tension by the drug was recorded with Isometric transducer(nacro F-60). The resting tension was approximately 0.5g. 2. The trachea smooth muscle of the isolated guinea pig was significantly relaxed by the administration of Haepyoyangjintang and Haepyoejintang extract. 3. The contractile response of the trachea smooth muscle of the isolated guinea pig to histamine$10^4M$ Was significantly inhibited by Heapyoyangjintang and Haepyoejintang extract. 4. The contractile response of the trachea smooth muscle of the isolated guinea pig to acetylcholine$10^4M$ was considerably inhibited by Haepyoyangjintang and Haepyoejintang extract. 5. The contractile response of the trachea smooth muscle of the isolated guinea pig to 5-hydorxytrtrypptamine $10^4M$ was considerably inhibited by Haepyoyangjintang and haepyoejintang extract.

• Structural Engineering and Mechanics
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• v.54 no.5
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• pp.909-922
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• 2015

The dynamic response and the mooring line tension of a 1/75 scale model of spar-type platform for 2.5 MW floating offshore wind turbine subject to one-dimensional regular harmonic wave are investigated numerically and verified by experiment. The upper part of wind turbine which is composed of three rotor blades, hub and nacelle is modeled as a lumped mass the scale model and three mooring lines are pre-tensioned by means of linear springs. The coupled fluid-rigid body interaction is numerically simulated by a coupled FEM-cable dynamics code, while the experiment is performed in a wave tank with the specially-designed vision and data acquisition system. The time responses of surge, heave and pitch motions of the scale platform and the mooring line tensions are obtained numerically and the frequency domain-converted RAOs are compared with the experiment.

• Structural Engineering and Mechanics
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• v.71 no.3
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• pp.291-303
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• 2019

In the paper the analysis of natural vibrations of the transmission line with use of spectral elements and the laboratory experiments is performed. The purpose of the investigation is to analyze the natural vibrations of the transmission line and compare with the results obtained in the numerical simulations. Particular attention is paid to the hysteretic and aerodynamic damping analysis. Sensitivity of the wave number is performed for changing of the tension force, as well as for the different damping parameters. The numerical model is made using the Spectral Element Method. In the spectral model, for various parameters of stiffness, damping and tension force, the system response is checked and compared with the results of the accelerations obtained in the measurements. A frequency response functions (FRF) are calculated. The credibility of the model is assessed through a validation process carried out by comparing graphical plots of FRF and time history analysis and numerical values expressing differences in acceleration amplitude (MSG), phase angle differences (PSG) and differences in acceleration and phase angle total (CSG) values. The next aspect constituting the purpose of this paper is to present the wide possibilities of modelling and simulation of slender conductors using the Spectral Element Method. The obtained results show good accuracy in the range of both experimental measurements as well as simulation analysis. The paper emphasizes the ease with which the sensitivity of the conductor and its response to changes in density of spectral mesh division, tensile strength or material damping can be studied.

• Structural Engineering and Mechanics
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• v.53 no.5
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• pp.997-1016
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• 2015

The contribution of tensioned concrete between cracks (tension-stiffening) cannot be ignored when analysing deformation of reinforced concrete elements. The tension-stiffening effect is crucial when it comes to adequately estimating the load-deformation response of steel reinforced concrete and the more recently appeared fibre reinforced polymer (FRP) reinforced concrete. This paper presents a unified methodology for numerical modelling of the tension-stiffening effect in steel as well as FRP reinforced flexural members using the concept of equivalent deformation modulus and the smeared crack approach to obtain a modified stress-strain relation of the reinforcement. A closed-form solution for the equivalent secant modulus of deformation of the tensioned reinforcement is proposed for rectangular sections taking the Eurocode 2 curvature prediction technique as the reference. Using equations based on general principles of structural mechanics, the main influencing parameters are obtained. It is found that the ratio between the equivalent stiffness and the initial stiffness basically depends on the product of the modular ratio and reinforcement ratio ($n{\rho}$), the effective-to-total depth ratio (d/h), and the level of loading. The proposed methodology is adequate for numerical modelling of tension-stiffening for different FRP and steel reinforcement, under both service and ultimate conditions. Comparison of the predicted and experimental data obtained by the authors indicates that the proposed methodology is capable to adequately model the tension-stiffening effect in beams reinforced with FRP or steel bars within wide range of loading.

• Structural Engineering and Mechanics
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• v.54 no.3
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• pp.501-520
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• 2015

Presence of torsional loadings can significantly affect the flow of internal forces and deformation capacity of reinforced concrete (RC) columns. It increases the possibility of brittle shear failure leading to catastrophic collapse of structural members. This necessitates accurate prediction of the torsional behaviour of RC members for their safe design. However, a review of previously published studies indicates that the torsional behaviour of RC members has not been studied in as much depth as the behaviour under flexure and shear in spite of its frequent occurrence in bridge columns. Very few analytical models are available to predict the response of RC members under torsional loads. Softened truss model (STM) developed in the University of Houston is one of them, which is widely used for this purpose. The present study shows that STM prediction is not sufficiently accurate particularly in the post cracking region when compared to test results. An improved analytical model for RC square columns subjected to torsion with and without axial compression is developed. Since concrete is weak in tension, its contribution to torsional capacity of RC members was neglected in the original STM. The present investigation revealed that, disregard to tensile strength of concrete is the main reason behind the discrepancies in the STM predictions. The existing STM is extended in this paper to include the effect of tension stiffening for better prediction of behaviour of square RC columns under torsion. Three different tension stiffening models comprising a linear, a quadratic and an exponential relationship have been considered in this study. The predictions of these models are validated through comparison with test data on local and global behaviour. It was observed that tension stiffening has significant influence on torsional behaviour of square RC members. The exponential and parabolic tension stiffening models were found to yield the most accurate predictions.

• Transactions of the Korean Society of Automotive Engineers
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• v.4 no.6
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• pp.109-120
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• 1996

Serpentine belt drive system offers the advantages of light weigh, low cost, quientness, and efficiency. Since these belts are typically longer than conventional belts, a tensioner component is added to maintain acceptable belt tension levels and make no slippage between pulleys and belts. This paper addresses the modeling and analysis of the automotive belt drive systems and also addresses the predicton of slippage on rotational modes. Vibration characteristics are determined from the eigenvalue problem governing the free response. Under certain engine operating conditions, the dynamic tension fluctuations may be sufficient to cause the belt to slip on particular accessory pulleys, It is found that this slippage can be reduced by adding the tensioner component from the analysis of belt tension and belt compression.

• Journal of KSNVE
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• v.8 no.2
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• pp.324-330
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• 1998

The forced vibration analysis of the outer-clamped spinnig annular disk with arbitrary in-plane is formulated to investigate the influence of non-uniform tension on the cutting accuracy of wafer cutting machine. The arbitrary in-plan force along the outer edge of an annular plate is expressed as a Fourier series. Galerkin method and modal superposition method are employed to obtain the forced responses under the static force and the impulse force in astationary coordinate. Through qualitative and quantitative analyses, it can be found that forced and impulse responses are sensitive to the non-uniformity of in-plane force, which can bring a bad effect to the accuracy of wafer cutting process. Also, in case of a spinning disk with non-uniform in-plane force, critical speed is required to define in a different way, compared with conventional definition in axi-symmetrical spinning disk.

• Ocean Systems Engineering
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• v.3 no.2
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• pp.149-165
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• 2013

Tension leg platforms (TLP's) are highly nonlinear due to large structural displacements and fluid motion-structure interaction. Therefore, the nonlinear dynamic response of TLP's under hydrodynamic wave loading is necessary to determine their deformations and dynamic characteristics. In this paper, a numerical study using modified Morison Equation was carried out in the time domain to investigate the influence of nonlinearities due to hydrodynamic forces and the coupling effect between all degrees of freedom on the dynamic behavior of a TLP. The stiffness of the TLP was derived from a combination of hydrostatic restoring forces and restoring forces due to cables and the nonlinear equations of motion were solved utilizing Newmark's beta integration scheme. The effect of wave characteristics was considered.

• Journal of the Korean Society for Precision Engineering
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• v.21 no.11
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• pp.171-178
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• 2004

This paper presents vibration characteristics of a wire cut discharge machine in which an electro-rheological brake actuator is used to control the wire tension. The ER brake actuator has several advantages including design simplicity, fast response time and real-time controllability. On the basis of the tension level required in the machine an appropriate size of the ER brake actuator is devised. The ER brake actuator is then incorporated with the machine and the field-dependent wire tension is experimentally evaluated. The straightness of the workpiece is also empirically investigated by changing the intensity of the electric field.