• Journal of the Korea institute for structural maintenance and inspection
• /
• v.1 no.1
• /
• pp.75-87
• /
• 1997

To study the behavior a deck when it was collide with the ship approaching to the deck to berth, it was analyzed the effect zone by the ship collision which consists of deck slab and PC piles of the quay. The numerical technique is used to simulate the behavior of the deck when the ship hit the expansion joint of deck between the deck slabs. The failure behavior and zone of the deck are determinated by the comprehensive numerical study. The impact energy by the ship is also evaluated. It is concluded that these numerical analysis gave a reasonable estimation of the remedial area of the deck damaged by ship collision.

• Journal of Aerospace System Engineering
• /
• v.8 no.3
• /
• pp.14-19
• /
• 2014

When a helicopter lands on a ship deck in high sea states, one of main difficulties is the ship motion by sea wave, In case of a manned helicopter, a pilot lands a helicopter on the deck during quiescent period of ship motion, which is perceived from different visual cues around landing spot. The capability to predict this quiescent period is very important especially for shipboard recovery of VTOL UAV in harsh environments. This paper describes how to predict heave motion of a ship for shipboard landing of a VTOL UAV. For simulation, ship motion by sea wave was generated using a 4,000 ton class US destroyer model. Heave motion of ship deck was predicted by applying auto-regression method to generated time series data of ship motion.

• Journal of the Korea Institute of Military Science and Technology
• /
• v.14 no.5
• /
• pp.871-879
• /
• 2011

The internal deck structure of turtle ship has been investigated with the following approach manner. Firstly the 5 species of turtle ship are identified by examining the characteristics of 5 turtle ships revealed by the librarian or paintings. Secondly the centers of gravity and buoyancy for each type are calculated to evaluate the turtle ship's buoyancy stability. Thirdly the optimal deck structures for 5 turtle ships are additionally assessed from the viewpoint of the interoperability of soldier's missions to get more meaningful conclusion. From the results obtained by the well refined analyses above, one can identify that Changjeguyseon and Lee Chung Mu Gong descendent family's turtle ship possess one layer deck, and the tongjeyoung and jwasuyoung turtle ship consist of 1 and half story deck, and the one disclosed by Yoon has 2 story structure.

• Journal of the Society of Naval Architects of Korea
• /
• v.42 no.3
• /
• pp.249-258
• /
• 2005

Recently, the vibration reduction at a local structure such as compass deck has been continuously requested by ship owner and shipbuilder. Because crews are afflicted with vibration, severe vibration problems even bring about a damage of structure. This study conducted to get an optimized stiffener size of compass deck to reduce the vibration level and decrease the weight of structure in ship. NASTRAN external call type optimization software (OptShip) which makes use of NASTRAN as a solver is used as an optimization tool. The results indicate that the optimum design is promising for real applications.

• Proceedings of KOSOMES biannual meeting
• /
• 2018.06a
• /
• pp.173-173
• /
• 2018

• Journal of Korea Fishing Vessel Association
• /
• v.29
• /
• pp.15-20
• /
• 1986

This paper describes on the measurement of the deck vibration produced by the main engine vibration of stern trawler MIS SAE-BA-DA (2,275GT, 3,600PS) while the ship is cruising and drifting. The obtained results are as follows; 1. The deck vibration level was the highest point at vertical line which pass main engine and the lowest point at vertical line which pass top bridge while the crusing. 2. The vibration source level of the main engine, screw shaft and screw propeller were respectively 110, 90 and 80% while the crusing. 3. The main deck vibration pressure level at the check points 2, 20, 30, 40, 60, 70, 80, 86m from the bow to stern was respectively 9, 8, 7, 10, 22, 45, 18, 23%. 4. The frequency distributions of the main engine, screw shaft, screw propeller vibration were from 3Hz to 10KHz, predominant frequency was 1KHz, each vibration accelration the highest level were respectively 1.3, 0.8, 0.5mm/$S^2$. 5. The predominant frequency distributions of the main deck, second deck, bridge deck and top bridge deck's vibration were from 10 to 30Hz, and each vibration accelration level were respe¬ctively 0.7, 0.05, 0.07, 0.04mm/$S^2$.

• Journal of the Society of Naval Architects of Korea
• /
• v.31 no.3
• /
• pp.119-128
• /
• 1994

Deflection estimation at engine room upper deck panel is performed for the actual ship structure. These deflection behaviours are basically investigated from not only the data based on the full series results of nonlinear analysis using Incremental Galerkin's Method but also actual deflection data measured from damaged ship under construction in dry dock. The effects of residual stress, initial deflection and static loading are also included. The computed estimation results of upper deck plate panel including theme effects are shown that upper deck platings of new ship expected less deflection magnitude than damaged ship.

• Selected Papers of The Society of Naval Architects of Korea
• /
• v.1 no.1
• /
• pp.37-44
• /
• 1993

Deck wetness phenomenon has long been considered as one of the factors that degrade the performance of a ship In waves. In rough weather, the frequent skipping of water may give rise to the capsizing of the ship. Therefore an appropriate above water bow shape design is an important asset to a ship of which successful performance in rough weather is a prerequisite such as a warship. In this paper an experimental technique for estimation of deck-wetness frequency is presented. The results of the model tests are compared with those of computations using Ochi's formula. Finally the applicability of Ochi's formula is discussed.

• Journal of the Society of Naval Architects of Korea
• /
• v.56 no.4
• /
• pp.343-351
• /
• 2019

Green water impact may sometimes cause some structure damages on ship's bow deck. Prediction of proper design pressure against the green water impact is an essential task to prevent the possible damages on bow deck. This paper presents a computational method of the bow deck's design pressure against the green water impact. Large heave and pitch motions of ship are calculated by the time domain nonlinear strip method. Green water flow and pressure on bow deck are simulated by the predictor-corrector second kind upstream finite difference method. This green water simulation method is based on the shallow water wave equations expanded for moving bottom conditions. For various kind of ships such as container ship, VLCC, oil tanker and bulk carrier, the green water design pressures on bow deck are computed and discussed. Also, the obtained results of design pressure on bow deck are compared with those of the classification society rules and discussed.

• Journal of the Korean Society of Fisheries and Ocean Technology
• /
• v.22 no.3
• /
• pp.23-28
• /
• 1986

This paper describes on the measurement of the deck vibration produced by the main engine vibration of stern trawler MjS SAE-BA-DA (2,275GT, 3,600PS) while the ship is cruising and drifting. The obtained results are as follows; 1. The deck vibration level was the highest point at vertical line which pass main engine and the lowest point at vertical line which pass top bridge while the crusing. 2. The vibration source level of the main engine, screw shaft and screw propeller were respectively 110, 90 and 80% while the crusing. 3. The main deck vibration pressure level at the check points 2, 20, 30, 40, 60, 70, 80, 86m from the bow to stern was respectively 9, 8, 7, 10, 22, 45, 18, 23%. 4. The frequency distributions of the rr.ain engine, screw shaft, screw propeller vibration were from 3 Hz to 10 KHz, predominant frequency was 1 KHz, each vibration accelration the highest level were respectively 1. 3, 0.8, 0.5 $mm/s^2.$ 5. The predominant frequency distributions of the main deck, second deck, bridge deck and top bridge deck-s vibration were from 10 to 30 Hz, and each vibration accelration level were respectively 0.7, 0.05, 0.07, 0.04 $mm/s^2.$