• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• 2004.04a
• /
• pp.197-202
• /
• 2004

It is well known that the hydrodynamic interaction forces between ship and bank wall affect ship manoeuvring motion. This paper deals with the interaction effect acting on a ship navigating closely in the proximity of bank wail. In this paper, the calculation method based on the slender body theory for estimation of the hydrodynamic interaction forces between ship and bank wail is applied. The hydrodynamic interaction forces acting on a ship during passing through the proximity of the bank wail are predicted to evaluate an influence of these interaction forces on ship manoeuvrability. The calculation method used in this paper will be useful for prediction of ship manoeuvrability at the initial stage of design, for automatic control system of ship in confined waterways, for discussion of marine traffic control system and for construction of harbour.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 1997.10a
• /
• pp.286-289
• /
• 1997

In the design of structure the forces acting on the structure are important parameter for noise and vibration control. However, in the complex structure, the forces at the injection pomt on the structure cannot be measured directly. Thus it is necessary to find out indirect force evaluation method. In thls paper forces have been measured with in-situ vibration responses and system information. Three existing techniques of indirect force measurement, viz. direct inverse, principal component analysis and regularization have been compared. It has been shown that multi-vibration responses are essential for the precise estimation of the forces. To satisfy those cond~tions, Rotary compressor is adopted as test sample, because it is very difficult to measurc the injection forces from internal excitat~on to shell. It has also been obtained that relatively higher force IS transmitted through three welding paths to the compressor shell. It shows a good agreement between direct and indirect force evaluation wlth curvature shell and plate and is investigated the possibility of force evaluation of rotary compressor as a complex structure.

• Journal of Navigation and Port Research
• /
• v.28 no.5
• /
• pp.333-337
• /
• 2004

It is well known that the hydrodynamic interaction forces between ship and bank wall affect ship manoeuvring motion This paper deals with the interaction effect acting on a ship navigating closely in the proximity of bank wall. In this paper, the calculation method based on the slender body theory for estimation of the hydrodynamic interaction forces between ship and bank wall is applied. The hydrodynamic interaction forces acting on a ship during passing through the proximity of the bank wall are predicted to evaluate an influence of these interaction forces on ship manoeuvrability. The calculation method used in this paper will be useful for prediction of ship manoeuvrability at the initial stage of design, for automatic control system of ship in confined waterways, for discussion of marine traffic control system and for construction of harbour.

• Journal of Power System Engineering
• /
• v.12 no.1
• /
• pp.41-46
• /
• 2008

The primary objective of this study is to truly understand exciting forces of the in-line 4 cylinders engine. Exciting forces of the engine apply a source of the vehicle NVH(Noise, Vibration, Harshness). To understand exciting forces, first was governed theoretical equations for single cylinder engine. And this theoretical equations was programming using MATLAB software. To compare theoretical analysis value, was applied MSC.ADAMS software. To determined the specification of engine(2,000cc, in-line 4) was applied ADAMS/Engine module. And this specification for engine was applied ADAMS/View and MATLAB software. The geometry model for ADAMS/View analysis was produced by the 3-D design modeling software. After imported 3-D model, each rigid body was jointed suitable. Under idle speed for engine, was analysed. The results of analysis are fairly well agreed with those of three analysis method. Using MATLAB software proposed in this study, engine exciting fores can be predicted. Also using ADAMS/Engine module and ADAMS/View software, engine exciting forces can be predicted.

• International Journal of Naval Architecture and Ocean Engineering
• /
• v.13 no.1
• /
• pp.718-733
• /
• 2021

A prediction method, based on the Morison equation as well as Froude-Krylov formula, is presented to simulate the loads acting on the columns and caissons of the semi-submersible platform induced by Internal Solitary Wave (ISW) respectively. Combined with the experimental results, empirical formulas of the drag and inertia coefficients in Morison equation can be determined as a function of the Keulegan-Carpenter (KC) number, Reynolds number (Re) and upper layer depth h₁/h respectively. The experimental and calculated results are compared. And a good agreement is observed, which proves that the present prediction method can be used for analyzing the ISW-forces on the semi-submersible platform. Moreover, the results also demonstrate the layer thickness ratio has a significant effect upon the maximum horizontal forces on the columns and caissons, but both minimum horizontal and vertical forces are scarcely affected. In addition, the incoming wave directions may also contribute greatly to the values of horizontal forces exerted on the caissons, which can be ignored in the vertical force analysis.

• Structural Engineering and Mechanics
• /
• v.82 no.4
• /
• pp.491-502
• /
• 2022

A model experiment with a scale of 1:150 has been conducted to investigate the dynamic responses of a freestanding four-column bridge tower subjected to regular wave, random wave and coupled wave-current actions. The base shear forces of the caisson foundation and the dynamic behaviors of the superstructure were measured and analyzed. The comparisons of the test values with the theoretical values shows that wave-induced base shear forces on the bridge caisson foundation can be approximated by using a wave force calculation method in which the structure is assumed to be fixed and rigid. Although the mean square errors of the base shear forces excited by joint random wave and current actions are approximately equal to those excited by pure random waves, the existence of a forward current increases the forward base shear forces and decreases the backward base shear forces. The tower top displacements excited by wave-currents are similar to those excited by waves, suggesting that a current does not significantly affect the dynamic responses of the superstructure of the bridge tower. The experiment results can be used as a reference for similar engineering design.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2002.05a
• /
• pp.425-430
• /
• 2002

This thesis is a study on behavior for anchorage zone in prestressed double T beam using strut-tie model. Stress conditions of Anchorage zone in prestressed double T beam are very disturbed because large concentrated forces act on relatively small areas. Hence, anchorage zone must be considered in Design of prestressed double T beam. If irrational design or irrational construction be conducted, that may lose stability in capacity as structure. In current design practice, certain parts of structure are designed with extreme accuracy, while anchorage zone in prestressed double T beam is designed using common sense, and experience. Therefore, it is generally very conservative. For that reason, logical, reasonable concept and accuracies are desired at design of anchorage zone in prestressed double T beam. Strut-tie method satisfies those desires. In this thesis, anchorage zone in prestressed double T beam is analyzed by considering prestressing forces. Strut-tie model is constructed based on principle stress trajectory obtained from 3D-finite element analysis in anchorage zone, and amounts of reinforcement be obtained. Results of analysis are compared with the way used in current design practice, and this thesis presents that strut-tie model can be an economical design than current design methods without losing the degree of safety.

• Journal of the Korean Society of Hazard Mitigation
• /
• v.1 no.2 s.2
• /
• pp.103-114
• /
• 2001

As the results of comparison with several anchorage design methods of PSC box girder, stress superposition effect by the order of prestressing force can't be considered in the case of multi-anchorage design with existing design methods. In anchorage design by 3-D finite element analysis, estimation of stress concentration region and stress flow are correctly defined, but the estimation of sectional forces in anchorage is very complicated. In the case of anchorage design by strut-tie model method, the stress superposition effect can be considered and sectional forces in anchorage are easily calculated. Therefore, strut-tie model method is remarkably suitable to anchorage design if geometrical conditions of the truss members are carefully considered.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 1996.11a
• /
• pp.891-895
• /
• 1996

Performance and efficiency of hybrid (hydraulic-mechanical) pick-up device of deep sea manganese nodules collector are very sensitive to altitude and altitude of pick-up head relative to undulating seafloor. For this reason, motion control of pick-up head relative to the changing deep sea topography and other disturbances is of particular importance in design of pick-up device. The concept of design axiom is applied to a pick-up device of hybrid type. Kinematic analysis conducted in absolute Cartesian coordinates gives position, velocity, and acceleration of the hydraulic cylinders which enable the pick-up head to keep the preset optimal distance from seafloor. Inverse dynamic analysis provides the driving forces of hydraulic cylinders and the reaction forces at each joint. Design sensitivity analysis is performed in order to investigate the effects of possible design variables on the change of the maximum strokes of hydraulic cylinders. The direct differentiation method is used to obtain the design sensitivity coefficients.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.14 no.2
• /
• pp.1-8
• /
• 2006

In this paper, an optimum design technology is developed to find an optimal position of the shock absorber using ADAMS and VisualDOC. A vehicle with a torsion-beam rear suspension is modeled by using ADAMS. Design variables for the optimal positioning of the shock absorber are defined considering the hard points of the chassis structure and design positioning are specified through the sensitivity analysis using a bump-crossing simulation. The objective function is defined as the joint reaction forces of the shock absorber connecting joints of the chassis structure. Sequential Quadratic Programming and Genetic Algorithms are used for this study. To validate the optimized design variables, pothole simulations are performed. GA showed better results than SQP algorithms for this design purpose.