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IJOCE (International Journal of Offshore and Coastal Engineering)
ISSN : -     EISSN : 25800914     DOI : -
Core Subject : Engineering,
IJOCE, International Journal of Offshore and Coastal Engineering, is an academic journal on the issues related to offshore, coastal and ship science, engineering and technology. Published quarterly in February, May, August, and November.
Arjuna Subject : -
Articles 6 Documents
Search results for , issue "Vol 5, No 1 (2021)" : 6 Documents clear
Analysis of the Effect of Abrasive Material and Polyurethane Coating Thickness Variations on ASTM A36 Steel Towards Corrosion Rate in Sea Water Environment Herman Pratikno; Felita Widya Hapsari; Wimala Lalitya Dhanista
International Journal of Offshore and Coastal Engineering (IJOCE) Vol 5, No 1 (2021)
Publisher : DRPM (Direktorat Riset dan Pengabdian kepada Masyarakat) ITS

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12962/j2580-0914.v4i3.9953

Abstract

An unavoidable phenomenon of using steel as the main material in offshore structures and floating vessels is corrosion. One method of preventing corrosion is by coating and using polyurethane is one type of coating that is currently being developed in the maritime industry. But the success of this coating process is very dependent on the surface preparation process. The usual method used is blasting using an abrasive material. This study aims to find the response to the corrosion rate of polyurethane coating with thickness variations of 60 µm, 80 µm, and 100 µm by first blasting using abrasive material variations in the form of silica sand and steel grit. The result of the corrosion rate test showed that the lowest corrosion rate value was obtained in the variation of abrasive material in the form of steel grit. with a 100. µm of polyurethane coating thickness, that is 0,00008 mm/a. While the highest corrosion rate value was obtained in the variation of abrasive material in the form of silica sand with a 60 µm of polyurethane coating thickness, that is 0,02202 mm/a. 
Influence Analysis of Shielding Gas Flow Rate and Purity Level Variation on GMAW Welding Process to Microstructure of Alumunium 5083 Nur Syahroni; Sadewa Sechan Winando; Yeyes Mulyadi
International Journal of Offshore and Coastal Engineering (IJOCE) Vol 5, No 1 (2021)
Publisher : DRPM (Direktorat Riset dan Pengabdian kepada Masyarakat) ITS

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12962/j2580-0914.v4i3.9954

Abstract

Aluminium is a commonly used material in construction and transportation industries. The advantages of using the aluminium material are its light weight, corrosion resistant, and the capability to form an alloy with another metal. Therefore, the aim of this research is to analyze the influence of shielding gas flow rate and purity level variation to mechanical properties and microstructure of the welded material. The welding process used on this research was the GMAW method. The material used was aluminium 5083 series with 300 mm x 150 mm x 8 mm dimensions. The shielding gases used were high purity (HP) and ultra-high purity (UHP) argon (Ar). The variations of shielding gas flow rate used were 16, 18, dan 20 litre/minutes. Based on the tensile test that has been done, the variation of UHP argon gas with 20 litre/minute flow rate had the best result with yield strength of 217,32 MPa and ultimate strength of 295,83 MPa. The result of the micro photos showed that the GMAW method produced small dots where the dots were Mg2Si formation, which the greater number of smaller size dot produced would increase the mechanical properties of  the material.
The Effect Analysis of Coating Thickness Variation and Mixture Composition of Magnesium – Flake Glass on Epoxy Coating on Abrasive Resistance, Adhesion Strength, and Prediction of Corrosion Rate of ASTM A36 Steel Plate Herman Pratikno; Yudiardana Tridantoko Susarno; Hasan Ikhwani
International Journal of Offshore and Coastal Engineering (IJOCE) Vol 5, No 1 (2021)
Publisher : DRPM (Direktorat Riset dan Pengabdian kepada Masyarakat) ITS

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12962/j2580-0914.v4i3.9956

Abstract

Steel cannot be separated from the marine manufacturing industry. It is important to control the corrosion rate of steel used for offshore structures. The coating method can be used in mobilization areas and splash zones that have high corrosion rates due to sustained friction loads in the marine environment. The purpose of this study was to analyze the different in adhesion strength, abrasion resistance, and corrosion rate prediction of ASTM A36 low carbon steel plate with coating thickness variations of 300µm, 500µm, and 700µm and Magnesium Carbonate - Flake Glass mixture variations of 10%, 20%, and 30%. In the pull-off test, the highest value of adhesion strength was obtained from specimen with 300µm coating thickness and 10% Magnesium Carbonate - Flake Glass mixture with a value of 5.67 Mpa. The highest abrasion test value was obtained from specimen with 700µm coating thickness and 30% Magnesium Carbonate - Flake Glass mixture with a value of 0.91 Wear Cyces per Micrometer. Whereas in the three cells electrode test, the highest value was found at specimen with 700µm coating thickness and 30% Magnesium Carbonate - Flake Glass mixture with a value of 0,00010 mmpy.
Experimental & Numerical Studies of Vertical Motion Acceleration Analysis in Helideck on a Catamaran Floating Crane Yunan Setiawan Suwandono; Eko Budi Djatmiko; Murdjito Murdjito; Abdul Ghofur
International Journal of Offshore and Coastal Engineering (IJOCE) Vol 5, No 1 (2021)
Publisher : DRPM (Direktorat Riset dan Pengabdian kepada Masyarakat) ITS

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12962/j2580-0914.v4i3.9955

Abstract

This research discusses the operability of vertical acceleration in the helideck. The experiment was carried out at the Maneuvering and Ocean Engineering Basin (MOB) facility of the BPPT-ITS Hydrodynamics Technology Center. The model being tested is the catamaran type with a scale of 1:36 to the original scale. Experimental testing using random waves with a Pierson-maskowitz spectrum with Hs = 2.5 and Hs = 6.37 m. The helideck only performs surge sway and heave tests. Meanwhile, numerical analyzes the effects of regular waves at heading 00 450 900 1350 1800 and obtained RAO for Heave, Roll, Pitch movements. For the analysis of landing operability at Helideck using the Olson and Marine criteria, where the limit of wave height according to Olson is obtained, namely for the incoming wave direction of 00, 900,1800, it should not be done more than 3 meters of wave height, while for conditions 450 and 1350 should not be above 4 meters. . For the HCA category, the critical condition when the direction of the wave of 900 with a wave height of 2 meters. At an altitude of 4 meters is the limit of the wave direction 00 450 1350 1800.
Experimental Study and Numerical Analysis of Floating Crane Catamaran Mooring Tension in Intact and Damage Conditions Using Time-Domain Approach Mochamad Hanif Rafi’i; Eko Budi Djatmiko; Murdjito Murdjito; Erdina Arianti
International Journal of Offshore and Coastal Engineering (IJOCE) Vol 5, No 1 (2021)
Publisher : DRPM (Direktorat Riset dan Pengabdian kepada Masyarakat) ITS

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12962/j2580-0914.v4i3.9957

Abstract

Floating Crane Catamaran equipped with a mooring system to keep stable while operating. During operation, wave load causes tension on the mooring system. In this study, the tension of the mooring system was analyzed using experimental studies and numerical analysis with intact and damaged mooring conditions. Experimental studies were carried out by simulating a physical model in the Ocean Basin Maneuvering Laboratory, BTH-BPPT. While numerical using related software. Mooring tension analysis is carried out using the frequency domain approach which refers to the API RP 2SK rules. The sum of the average tension, significant low frequency tension and maximum wave frequency tension is the maximum tension of the mooring system. The low frequency tension and wave frequency tension is obtained by the low-band-pass filter process. The stochastic value is obtained by the FFT of low frequency and wave frequency tension. The results of maximum tension from experimental and numerical at intact conditions, wave headings 90°, Hs  2.5 m, are 373.7 kN and 441.6 kN and at Hs  6.37 m are 565.6 kN and 1741.5 kN. In the damaged condition, wave heading 90°, Hs 2.5 m, the maximum tension is 863.9 kN and 2113.3 kN.
Local Stress Analysis in the Chain Link of Mooring Line That Had Diameter Degradation Rafliansyah Azhar Putera; Eko Budi Djatmiko; Murdjito Murdjito
International Journal of Offshore and Coastal Engineering (IJOCE) Vol 5, No 1 (2021)
Publisher : DRPM (Direktorat Riset dan Pengabdian kepada Masyarakat) ITS

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12962/j2580-0914.v4i3.9952

Abstract

Mooring systems are used to moored ships at a particular area. One of its type is SPM by using a buoy. The system generally uses chains used to tie buoys to the seabed. However, chains that are used continuously can experience degradation in the diameter of the chain connection. The degradation experienced by the connections between the chains will certainly affect the local ( von Mises stress).  According to ABS rules, the amount of local stress or von Mises stress that occurs on an object must not exceed 90% of the yield strength of the material. Therefore, it is necessary to do a local stress analysis to determine the extent of degradation of the diameter of the chain connection so that the local stress value does not exceed that allowed. The largest mooring tension value that occurs in the mooring system is 1838,252 kN. The results show that if the chain connection is subject to a tension of 1838,252 kN, the diameter degradation that occurs in the chain connection must not exceed 15% of the initial diameter so that the local or von Mises stress does not exceed 369 MPa (90% of the yield strength of the material 410 MPa).

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