• Transactions of the Korean Society of Mechanical Engineers A
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• v.40 no.7
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• pp.621-628
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• 2016

This paper presents the development of a deadweight type 6-component force/moment generator for estimating characteristics of multi-component loadcell. Several new methods in moment generation are introduced in order to produce accurate force / moment and to minimize coupling effect between each force or moment components. In order to verify the reliability of the calibration system developed, estimation of the method for generating moment components and cross measurements between force or moment components are carried out utilizing a commercial torque cell and both-ends fixed beam designed in this paper.

• Journal of the Korean Society of Marine Environment & Safety
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• v.15 no.1
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• pp.57-62
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• 2009

In order to investigate the hydrodynamic interaction between the tug-barge and bank or ship which is crossing to the opposite direction, the towing simulations of tug-barge transportation were performed. Heading of barge, yaw moment and lateral force of tug boat were obtained by this simulation. The characteristics of results were analyzed and the safety towing method for tug-barge operation was proposed. In order to reduce the slewing motion of barge for safe towing operation, the speed of tug boat should be kept slow ahead state with shortened towing line as length of barge within the limits of the possible.

• Journal of Korean Tunnelling and Underground Space Association
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• v.11 no.4
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• pp.427-435
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• 2009

This study deals with the analytical solution for soil-lining interaction in a deep and circular tunnel. Simple closed-form analytical solutions for thrust and moment in the circular tunnel lining due to static and seismic loadings are developed by considering the relations between displacement and interaction forces at the soil-lining interface. The interaction effect at the soil-lining interface is considered with new ratios (the normal and shear stiffness ratios). The effects of the ratios on the normalized thrust and the normalized moment are investigated.

• Proceedings of KOSOMES biannual meeting
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• 2008.05a
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• pp.43-47
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• 2008

In order to investigate the hydrodynamic interaction between the tug-barge and bank or ship which is crossing to the opposite direction, we have executed the towing simulation of tug-barge transportation. Heading of barge, yaw moment and lateral force of tug boat are obtained by this simulation. We have analyzed the characteristics of results and propose the safety towing method for tug-barge operation.

• Journal of Ocean Engineering and Technology
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• v.28 no.6
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• pp.546-551
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• 2014

This paper addresses a feedback linearization control problem for the nonlinear dynamics of an underwater glider system. We consider the buoyancy and moment as control inputs, which come from the mass variation and elevator control, respectively. Moment-to-force coupling increases the nonlinearities, which make the controller design difficult. By using a feedback linearization technique, we convert the nonlinear underwater glider to an equivalent linear model and design a linear controller. The controller for the equivalent converted linear system is designed using sufficient conditions in terms of linear matrix inequalities. Then, the control input of the nonlinear model of an underwater glider is formulated from the linear control input. An experimental examination is implemented to verify the effectiveness of the proposed technique.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.45 no.12
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• pp.1059-1068
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• 2017

Space exploration spacecraft carry large amounts of liquid fuel, often more than half. In such cases, the liquid fuel sloshing must be considered in the design of the spacecraft since the sloshing can affects the stability of the spacecraft. In this paper, we present the results of analyzing the sloshing of fuel and the dynamic behavior of the spacecraft. For the purpose, a model in which the maneuvering of the spacecraft causes the sloshing and a model in which the reaction force and moment due to the sloshing are transmitted to the spacecraft are developed. The dynamical behavior of the spacecraft are analyzed using a simulation program coded by Modelica.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.35 no.5
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• pp.277-286
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• 2022

The elastic and inelastic responses obtained from the experimental and analytical results of two RC building structures under the service level earthquake (SLE) and maximum considered earthquake (MCE) in Korea were used to weinvestigate the characteristics of the mechanisms resisting shear and torsional behavior in torsionally unbalanced structures. Equations representing the interactive effect of translational drift and torsional deformation on the shear force and torsional moment were proposed. Because there is no correlation in the behavior between elastic and inelastic forces and strains, the incremental shear forces and incremental torsional moments were analyzed in terms of their corresponding incremental drifts and incremental torsional deformations with respect to the yield, unloading, and reloading phases around the maximum edge-frame drift. In the elastic combination of the two dominant modes, the translational drift mainly contributes to the shear force, whereas the torsional deformation contributes significantly to the overall torsional moment. However, this phenomenon is mostly altered in the inelastic response such that the incremental translational drift contributes to both the incremental shear forces and incremental torsional moments. In addition, the given equation is used to account for all phenomena, such as the reduction in torsional eccentricity, degradation of torsional stiffness, and apparent energy generation in an inelastic response.

• Journal of the Korean Geotechnical Society
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• v.36 no.12
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• pp.27-34
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• 2020

Use of axisymmetric shell element for the structure increases the efficiency and accuracy in finite element analysis of the interaction between the ground and the structure. This paper derived the force balance equation and the moment balance equation for an axisymmetric shell element based on Kirchhoff's theory. The governing equation for the axial deformation used the isoparametric shape function in the Galerkin formulation, and the governing equation for the shell bending used the higher-order shape function. The developed axisymmetric shell element was combined with Geo-COUS, a geotechnical finite element program for the coupled analysis with the ground. The accuracy of the developed element was confirmed through the example analyses of the circular plate and the liquid storage tank. And the energy balance equation for the axisymmetric shell element is presented.