• Title/Summary/Keyword: Underwater steel plate

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A Study on the Corrosion Loss of Zinc Anodes of the Underwater Shell Plate (선저 아연판의 부식에 관한 연구)

  • Kim, Min-Suck;Lee, Jong-Mun;Kim, Jong-Hwa;Kang, Il-Kwon;Kim, Dong-Soo
    • Journal of Fisheries and Marine Sciences Education
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    • v.19 no.1
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    • pp.129-136
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    • 2007
  • The component parts of the shell plate of a ship are steel. but the screw propeller or the bow thruster is a compound of bronze, nickel and aluminum. On account of the these different components between metals of the shell plate, the screw propeller and the bow thruster, which are underwater, the shell plate of a ship is corroded by the action of ionization. Authors investigated the corrosion loss of the zinc anodes which were attached to the bottom shell of the training ship Kaya for about two years. The obtained results were as follows:1. In case of the shell plate the difference of the corrosion loss according to port and starboard was almost nothing. But the corrosion loss of the forward part was more than that of the aftward part.2. There was little difference in the corrosion loss between the forward and the aftward part on the bilge keel.3. The corrosion loss of the fore, midship and aft part on the false keel were 24.7%, 22.4% and 23.9% respectively.4. The corrosion loss of the fore and the aft part on the false keel was more than that of the midship part.5. The corrosion loss of the bow thruster was greater than any other parts.6. The nearer the zinc anode to the screw propeller the more the corrosion loss on the stern frame, and the situation was also same as on the rudder.

Explosion Bulge Test Underwater of 800MPa Grade Pre-heat Free Welding Plate (800MPa급 무예열 용접 판재의 수중 폭파변형시험)

  • Park, Tae-Won;Song, Young-Beum;Kim, Jin-Young;Yang, Sung-Ho;Park, Chul-Gyu;Seo, Jun-Suck;Kim, Hee-Jin
    • Journal of Welding and Joining
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    • v.28 no.6
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    • pp.63-69
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    • 2010
  • The pre-heat free consumables for GMAW, SAW and FCAW processes that matche with the Cu-bearing PFS-700 steel which has yield strength over 700MPa were developed and evaluated to see the suitability in military such as submarine and battle ship. Explosion Bulge Test underwater was developed and applied to see the reliability of welded structure. All welding was conducted without pre-heat before welding, the interpass temperature was below $150^{\circ}C$ for all welding conditions. Tensile strength for the weld metal in GMAW, SAW and FCAW process is 887MPa, 875MPa and 813MPa, respectively, these values are similar to the base metal of PFS-700 steel of 838MPa. EBT results in GMAW, SAW and FCAW show 14.0%, 14.02% and 15.9% reduction of thickness without generation of crack, respectively and stand-off distance was set up properly to have over 14.0% reduction of thickness. Through EBT results, the developed new consumables are applicable to the weapon systems such as submarine and battle ship.

Explosion Bulge Test in Underwater of 800MPa Grade Pre-Heat Free Welding Plate (800MPa급 무예열 용접 판재의 수중 폭파변형시험)

  • Park, Tae-Won;Song, Young-Bum;Kim, Jin-Young;Yang, Seong-Ho;Hong, Sung-Suk;Shim, In-Ok;Park, Chul-Kyu;Kim, Hee-Jin
    • Proceedings of the KWS Conference
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    • 2010.05a
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    • pp.63-63
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    • 2010
  • The pre-heat free consumables for GMAW, SAW and FCAW processes that matches the Cu-bearing PFS-700 steel which has yield strength over 700MPa were developed and evaluated to see the suitability in military such as submarine and battle ship. Explosion bulge test in underwater was developed and applied to see the reliability of welded structure. All welding was conducted without pre-heat before welding, the interpass temperature was below $150^{\circ}C$ for all welding conditions. Tensile strength for the weld metal in GMAW, SAW and FCAW process is 887MPa, 875MPa and 813MPa, respectively, these values are similar to the base metal of PFS-700 steel of 838MPa. EBT results in GMAW, SAW and FCAW show 14.0%, 14.02% and 15.9% reduction of thickness without generation of crack, respectively and stand-off distance was set up properly to have over 14.0% reduction of thickness. Through EBT results, the developed new consumables are applicable to the weapon systems such as submarine and battle ship.

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Analysis of Reducing Tonal Noise of the Gas Turbine Generator in order to Reduce Underwater Radiated Noise of a Naval Vessel (수중방사소음 저감을 위한 함정용 개스터빈 발전기의 순음 저감 분석)

  • Han, Hyung-Suk;Choi, Ki-Yong
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2009.10a
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    • pp.155-162
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    • 2009
  • Because the tonal sound of the underwater noise in a naval vessel can be identified from the sub-marine of the enemy, it should be reduced sufficiently. This kind of the noise usually comes from the structure-borne noise of the onboard machine and transfers to the sea through the hull of the ship. The vibration at the high frequency can be reduced sufficiently with damping material. In this paper, the damping coefficient of the steel plate with damping sheet is evaluated by experiment. Using these evaluated properties, the numerical analysis is performed in order to evaluate how much vibration of the generator can be reduced applying damping sheet on the encloser and base of it.

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Analysis of Reducing Tonal Noise of the Gas Turbine Generator in order to Reduce Underwater Radiated Noise of a Naval Vessel (수중방사소음 저감을 위한 함정용 개스터빈 발전기의 순음 저감 분석)

  • Han, Hyung-Suk;Choi, Ki-Yong
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.19 no.12
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    • pp.1329-1337
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    • 2009
  • Because the tonal sound of the underwater noise in a naval vessel can be identified from the sub-marine of the enemy, it should be reduced sufficiently. This kind of the noise usually comes from the structure-borne noise of the onboard machine and transfers to the sea through the hull of the ship. The vibration at the high frequency can be reduced sufficiently with damping material. In this paper, the damping coefficient of the steel plate with damping sheet is evaluated by experiment. Using these evaluated properties, the numerical analysis is performed in order to evaluate how much vibration of the generator can be reduced applying damping sheet on the encloser and base of it.

Assessment of Underwater Penetration Performance for the Shape of the External Device of Shaped Charge (성형폭약 외부장치 형상에 따른 수중 관입성능 평가)

  • Suk, Chul-Gi;Noh, You-Song;Ko, Young-Hun;Park, Hoon;Cho, Sang-Ho;Yang, Hyung-Sik
    • Explosives and Blasting
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    • v.34 no.4
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    • pp.1-9
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    • 2016
  • For underwater steel structure, cut that underwater shaped charge device that combines a spring hose, which is an external device of pressure resistance and flexibility with flexible shaped charge, was invented. As a basic experiment for an optimum condition design, an penetration performance was compared by external device shape. To evaluate the result of an experiment, image analysis was carried out after obtaining the model by using the liquid rubber for the penetrated steel plate. To simulate the penetrating process of shaped charge, the AUTODYN program has been used. As a result of analysis, while the average penetration depth of circular and square shaped external devices were similar, the penetration quality was more uniform in the case of circle. In addition, water infiltration occurred in square case, displacement and strain rate according to the increase of the water pressure were measured high.

Experimental and Numerical Studies on Application of Industrial Explosives to Explosive Welding, Explosive Forming, Shock Powder Consolidation (산업용 폭약을 이용한 폭발용접, 폭발성형과 충격분말고화에 관한 실험 및 수치해석적 연구)

  • Kim, Young-Kook;Kang, Seong-Seung;Cho, Sang-Ho
    • Tunnel and Underground Space
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    • v.22 no.1
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    • pp.69-76
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    • 2012
  • Theoretical backgrounds on the experimental methods of explosive welding, explosive forming and shock consolidation of powders are introduced. Explosive welding experiments of titanium (Ti) and stainless steel (SUS 304) plate were carried out. It was revealed that a series of waves of metal jet are generated in the contact surface between both materials; and that the optimal collision velocity and collision angle is about 2,100~2,800 m/s and $15{\sim}20^{\circ}$, respectively. Also, explosive forming experiments of Al plate were performed and compared to a conventional press forming method. The results confirmed that the shock-loaded Al plate has a larger curvature deformation than those made using conventional press forming. For shock consolidation of powders, the propagation behaviors of a detonation wave and underwater shock wave generated by explosion of an explosive are investigated by means of numerical calculation. The results revealed that the generation and convergence of reflected waves occur at the wall and center position of water column, and also the peak pressure of the converged reflected waves was 20 GPa which exceeds the detonation pressure. As results from the consolidation experiments of metal/ceramic powders ($Fe_{11.2}La_2O_3Co_{0.7}Si_{1.1}$), shock-consolidated $Fe_{11.2}La_2O_3Co_{0.7}Si_{1.1}$ bulk without cracks was successfully obtained by adapting the suggested water container and strong bonding between powder particles was confirmed through microscopic observations.