• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2005년도 춘계학술대회 논문집
• /
• pp.1412-1415
• /
• 2005

Special considerations on the design of liquid storage tanks should be taken into account for seismic and wind loads. But Korean industrial standard KS B 6225 does not specify detailed guidelines for a design. It is therefore necessary to improve design guidelines for a seismic and wind-proof design in KS B 6225. The purpose of this study is provide a basis for the development of improved seismic and wind-proof design procedures, especially about seismic and wind loads.

• Steel and Composite Structures
• /
• 제2권3호
• /
• pp.161-170
• /
• 2002

The problem of the elastic buckling of a cylindrical liquid-storage tank subject to horizontal earthquake loading is considered. An equivalent static loading is used to represent the dynamic effect. A theoretical solution based on the nonlinear Fl$\ddot{u}$gge shell equations is developed, and numerical results are found using the new differential quadrature method. A second solution is obtained using the finite element package ADINA. A major motivation of the study was to show that the new method can serve to verify finite element solutions for cylindrical shell buckling problems. For this purpose the paper concludes with a comparison of buckling results for a number of cases covering a wide range in tank geometry.

• 한국환경과학회지
• /
• 제18권12호
• /
• pp.1339-1347
• /
• 2009

This study tried to investigate and analyze the actual state such as the regional, classified, and material characteristics of the water quality in order to research the several factors by which the filtrated water of the total 250 cases can be polluted in the water tank. The 215 points (86%) clean the water tanks twice a year regularly and J-city has done the best job of cleaning the water tanks. The fifty points (20%) of the total 250 investigation points examine the water quality of the water tanks every year, however, the 175 investigation points (70%) do not execute the inspection of water quality. In the case of the regional characteristics in the water quality, the 23 points (46%) in H-county, the 17 points (34%) in S-county, and the 16 points (32%) in G-city are incongruent in the standard, and the incongruity ratio of the water quality in J-city is the lowest. The result of the classified incongruity shows that total coliforms were found at the 61 investigation points, mesophilic bacteria were found at the 27 points, and turbidity was found at the 12 points. In the case of the material incongruity, concrete was found at the 63 investigation points as the most distinguished factor, and FRP (fiberglass reinforced plastic) at the 23 points, SMC (sheet molding compound) at the 12 points, and stainless steel was found at the 2 points.

• 한국지진공학회논문집
• /
• 제22권5호
• /
• pp.261-269
• /
• 2018

This study examines earthquake-induced sloshing effects on liquid storage tanks using computation fluid dynamics. To achieve this goal, this study selects an existing square steel tank tested by Seismic Simulation Test Center at Pusan National University as a case study. The model validation was firstly performed through the comparison of shaking table test data and simulated results for the water tank subjected to a harmonic excitation. For a realistic estimation of the wall pressure response of the water tank, three recorded earthquakes with similar peak ground acceleration are applied:1940 El Centro earthquake, 2016 Gyeongju earthquake, and 2017 Pohang earthquake. Wall pressures monitored during the dynamic analyses are examined and compared for different earthquake motions and monitoring points, using power spectrum density. Finally, the maximum dynamic pressure for three earthquakes is compared with the design pressure calculated from a seismic design code. Results indicated that the maximum pressure from the El Centro earthquake exceeds the design pressure although its peak ground acceleration is less than 0.4 g, which is the design acceleration. On the other hand, the maximum pressure due to two Korean earthquakes does not reach the design pressure. Thus, engineers should not consider only the peak ground acceleration when determining the design pressure of water tanks.

• Corrosion Science and Technology
• /
• 제16권6호
• /
• pp.294-297
• /
• 2017

For the longer service life of steel pile, cathodic protection is selected sometimes at corrosive environment. The cathodic protection design improvement was investigated in this study. The current demand for cathodic protection was calculated from the potentiostatic current monitoring of the steel specimen in the deaerated soil samples. In this study, the current distribution was studied using the Boundary Element Method (BEM) and the Finite Element Method (FEM) numerical analysis methods. The optimum layout of the anode was developed and confirmed by numerical analysis. Under the conventional design of the anode, the length of the anode hole is same as the pile length. We found that, at the bottom end of the pile, the current density is too high. When the anode hole length was 80% of the pile length, the current consumption at the end was reduced. The construction cost of anode hole drilling was decreased about 20%, as compared to the conventional design. Furthermore, the life of the anode materials could be extended by reducing the current consumption at the end section. Using this approach, the construction cost was reduced significantly without any under-protection area on the steel piles.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 2001년도 ICCAS
• /
• pp.65.3-65
• /
• 2001

In order to apply for pickling line in cold rolling process, a high power magnetostrictive ultrasonic transducer was developed. The transducer is expected to overcome the shortcomings of conventional high power ultrasonic transducers. The transducer consists of Fe-Co-V alloy sheets for the magnetostrictive material, an ultrasonic horn made of Hastelloy to withstand acid solution, and electric driving circuit. In the development, the transducer was designed with the theoretical and numerical methods such as finite element method, and was characterized with experimental water tanks. The developed transducers turned out to be able to generate the sound pressure up to 20,000 Pa, and to be suitable for application ...

• 비파괴검사학회지
• /
• 제30권5호
• /
• pp.479-483
• /
• 2010

초저온 액화가스인 LNG의 저장탱크에 사용되는 9% 니켈강은 Inconel 혹은 Hastelloy 계열 용접봉을 사용하여 용접되며, 용접부는 저합금강과 오스테나이트 스테인리스강의 이종금속 용접부와 유사한 특성을 가지고 있다. 용접부에 대한 방사선투과시험 시 용접조건에 따라 밴드형태의 지시가 방사선투과 필름 상에 나타나곤 한다. 따라서 본 연구에서는 이에 대한 해석을 위하여 재료, 방사선투과시험, 초음파탐상시험, 액체침투탐상시험 및 조직시험을 통하여 의사지시 여부를 확인하였으며, 방사선투과시험 해석 및 밴드형태 지시의 발생 원인을 제시하였다.

• Structural Engineering and Mechanics
• /
• 제52권6호
• /
• pp.1273-1287
• /
• 2014

Plates are most widely used in the hulls of floating concrete structures, bridge decks, walls of off-shore structures and liquid storage tanks. A method of analysis is presented for the determination of load-deflection response and ultimate strength of high-strength steel fiber reinforced concrete (HSSFRC) plates simply supported on all four edges and subjected to combined action of external compressive in-plane and transverse loads. The behavior of HSSFRC plate specimens subjected to combined uniaxial in-plane and transverse loads was investigated. The proposed analytical method is compared to the physical test results, and shows good agreement. To predict the constitutive behavior of HSSFRC in compression, a non-dimensional characteristic equation was proposed and found to give reasonable accuracy.

• 수산해양교육연구
• /
• 제9권2호
• /
• pp.198-208
• /
• 1997

Recently, with rapid increase of gas demand, there occurs much interest their security of safety in the gas storage tanks and pressure vessels etc. In order to solve the problems, the occurrence of corrosion fatigue crack and the propagation behavior must be investigated. Especially the occurrence of corrosion fatigue crack and the propagation behavior in the part which has concentrated stress or defects, must be studied more carefully. In this paper, the high-tensile steel of SPV 50 which is much used for building the LPG storage tanks was tested by the use of a plane bending corrosion fatigue tester under the various marine environment and in the air. These experiments were carried out to investigate the surface crack propagation behavior, the value of experimental constant for Paris' rule(da/dN=$C(K)^m$), the crack depth propagation rate and the accelerative factor of the surface crack propagation rate. The main results obtained are as follows ; 1) As the specific resistances of marine environment decreases, the exponential value of slope m of Paris' rule(da/dN=$C(K)^m$) decreases and the value of intercept C increases. 2) The surface crack propagation rate and the crack depth propagation rate are delayed, as the specific resistances of marine environment is increased. 3) The accelerative factor of the surface crack propagation rate by corrosion fatigue is higher, according as the stress intensity factor range ${\Delta}K_A$ is small.

• Corrosion Science and Technology
• /
• 제5권2호
• /
• pp.69-76
• /
• 2006

Premature cracking of the epoxy coatings applied on ship's ballast tanks(BT) can lead to damage of ship's hulls. To avoid this, it's important to have clear understanding of the underlying mechanism and primary factors of the coating crack. In this study, the efforts were made to clarify the integrated effects of main factors, i.e., initial coating shrinkage, thermally induced strain, steel-structural strain and the intrinsic coating flexibility at the initial and after aging, to the early cracking phenomena of epoxy coating in the ship's ballast tank. The coating crack is caused by combination of thermal stress, structural stress, and internal stresses which is closely related to chemical structures of the coatings. On the other hand, thermal stresses and dimensional stabilities would rarely play a major role in coating crack for ballast tank coatings with rather large flexibility. Crack resistance of the coatings at early stages can be estimated roughly by measuring internal stress, FT-IR and $T_g$ value of the coatings. A new screening test method was also proposed in this study, which can be possibly related to the long-term resistance of epoxy-based paints to cracking.