• Proceedings of the Korean Society of Marine Engineers Conference
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• 2005.06a
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• pp.222-227
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• 2005

A Flapping foil produces an effective angle of attack, resulting in a normal force vector with thrust and lift components, and it can be expected to be a new highly effective propulsion system. A heaving foil model was made and it was operated within a circulating water channel at low Reynolds numbers. The unsteady thrust and lift acting on the heaving foil were measured simultaneously using a 6-axis force sensor based on force and moment detectors. We have been examined various conditions such as heaving frequency and amplitude in NACA 0010 profile. The results showed that thrust coefficient and efficiency increased with reduced frequency and amplitude. We also presented the experimental results on the unsteady fluid forces of a heaving foil at various parameters.

• International Journal of Naval Architecture and Ocean Engineering
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• v.7 no.2
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• pp.346-363
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• 2015

We have performed integrated dynamics modeling for a supercavitating vehicle. A 6-DOF equation of motion was constructed by defining the forces and moments acting on the supercavitating body surface that contacted water. The wetted area was obtained by calculating the cavity size and axis. Cavity dynamics were determined to obtain the cavity profile for calculating the wetted area. Subsequently, the forces and moments acting on each wetted part-the cavitator, fins, and vehicle body-were obtained by physical modeling. The planing force-the interaction force between the vehicle transom and cavity wall-was calculated using the apparent mass of the immersed vehicle transom. We integrated each model and constructed an equation of motion for the supercavitating system. We performed numerical simulations using the integrated dynamics model to analyze the characteristics of the supercavitating system and validate the modeling completeness. Our research enables the design of high-quality controllers and optimal supercavitating systems.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.35 no.7
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• pp.785-790
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• 2011

The goal of this study is to estimate the force acting on the knee joint in the human body by using the Hilltype muscle model based on a musculoskeletal model of the human lower extremity in the sagittal plane. For estimating the force applied, the human leg is modeled using multi-body modeling. This leg model comprises biarticular muscles acting on two joints of the upper and lower limbs, and the muscles include some of the major muscles such as the hamstring. In order to analyze the uncertainty of the applied forces acting on the knee joint, statistical distributions of human body, leg part, parameters are required and to obtain the parameter's statistical characteristic of the part sample survey method is employed. Finally, by using the sensitivity information of the parameters, the force acting on the knee joint can be estimated.

• Bulletin of the Society of Naval Architects of Korea
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• v.16 no.3
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• pp.21-24
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• 1979

The method of computing a hydrodynamic force induced by a random seismic motion of boundary is presented and a sway force acting on a platform during an earthquake is shown.

• Proceedings of KOSOMES biannual meeting
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• 2003.11a
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• pp.149-153
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• 2003

The hydrodynamic forces acting on the submerged plate are composed of diffraction and radiation forces. Thus we have carried out the extensive experiments and numerical simulations to make clear the characteristics of the diffraction and radiation forces on the submerged plate. These experimental results are compared with the numerical ones, and we discuss the effect of nonlinear on the hydrodynamic forces acting on the submerged plate. As a result, we get the conclusion that the submerged plate is useful for reducing the wave exciting forces on the structure behind the submerged plate.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2004.04a
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• pp.311-316
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• 2004

In order to secure the traffic safety especially in the entrance waterway of harbour, it is important that the breakwater and the port facilities should be designed properly considering ship-handling difficulty and traffic flow. In this study, the lateral force acting on ship hull under the external force(wind, current, wave) is investigated quantitatively for the container ship approaching to the Busan and Gamcheon breakwater. The relation of ship-handling difficulty to the breakwater and the arrangement of ship's routine are examined based on the lateral force under the external force. Some of reviews to secure traffic safety on the design of breakwater are discussed.

• Journal of Ocean Engineering and Technology
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• v.16 no.6
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• pp.7-17
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• 2002

Recently, artificial rocks, instead of buoys, have been placed on the submerged breakwater to indicate its location. The accurate estimation of wave forces on these rocks is deemed necessary for their stability design. Characteristics of the wave force, however, are expected . to be very complicated because of the occurrence of breaking or post-breaking waves. In this regard, wave forces exerted on an artificial rock have been investigated in this paper. The maximum wave force has been found to strongly dependent on the location and shape of the artificial rock that is placed on the submerged breakwater. The plunging breaker occurs near the loading cram edge of a submerged breakwater, which cause impulsive breaking wave force on the rock. Using the Morison equation, with the velocity and acceleration at the front face of the artificial rock and varying water surface level, it is possible to estimate wave forces, even impulsive breaking wave forces, that are acting on the rock installed on a submerged breakwater. The vertical wave force is also found to depend, significantly, on the buoyant force.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.7 s.178
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• pp.1871-1877
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• 2000

Longitudinal and lateral forces acting at tire are known to be closely related to the tractive ability, braking characteristics, handling stability and maneuverability of ground vehicles. However, it is not feasible in the operating vehicles to measure the tire forces directly because of high cost of sensors, limitations in sensor technology, interference with the tire rotation and harsh environment. In this paper, in order to develop tire force monitoring system, a new vehicle dynamics monitoring model is proposed including the roll motion. Based on the monitoring model, tire force monitoring system is designed to estimate the lateral tire force acting at each tire. A newly proposed SKFMEC (Scaled Kalman Filter with Model Emr Compensator) method is developed utilizing the conventional EKF (Extended Kalman Filter) method. Tire force estimation performance of the SKFMEC method is evaluated in the Matlab simulations where true tire force data is generated from a 14 DOF vehicle model with a combined-slip Magic Formula tire model.

• Journal of the Korean Society for Precision Engineering
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• v.16 no.4 s.97
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• pp.79-84
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• 1999

This paper focus on investigating the influence of the amount of water ingestion and the engine speed on the joint reaction force of the connecting rod in engine. The connecting rod was modelled by MSC/PATRAN, the modal informations of it were obtained by the DMAP module in the MSC/NASTRAN, and the dynamic force history was computed through the flexible multibody dynamic simulation in DADS. To analyze the joint reaction force acting on the connecting rod, the 48 cases were investigated. The engine speed varies with 200, 700, 1600, 2400rpm and the volumetric ratio of water to the combustion chamber varies with 0, 10, 20, ..., 90, 95 and 97.5% . As the engine speed decreases and the amount of water ingestion increases, the joint reaction force increase. Especially when the amount of water ingestion exceeds the 70% of the volume of the combution chamber, the joint reaction force acting on the connecting rod is over the design strength.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.26 no.5
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• pp.335-341
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• 2014

Physical experiments were carried out to measure the wave force on the vertical walls of perforated breakwater considering several phases of a wave acting on the breakwater. The maximum horizontal wave force acting on each vertical wall was compared between single and double chamber caisson breakwater. The experimental data in this study showed that the total horizontal wave force for double chamber caisson was 9.6% smaller on average than that for single chamber caisson when the total chamber width was the same for both caissons. Such reduction of the wave force is due to the dissipation of wave energy at the porous middle wall, which is located between the porous front wall and non-porous rear wall.