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FATIGUE ANALYSIS OF CATENARY MOORING SYSTEM DUE TO HARSH ENVIRONMENT IN FOLLOWING SEAS Assidiq, Fuad Mahfud; Paroka, Daeng; Alie, Muhammad Zubair Muis; Klara, Syerly
Jurnal Indonesia Emas PPI Dunia Vol 1 No 01 (2018): OISAA Journal of Indonesia Emas
Publisher : PPI Dunia

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Abstract

In the operation, Floating Production Unit (FPU) will get dynamic loads on the structure periodically such as the mooring line responses. The aim of the present study to discuss fatigue life on catenary mooring system refers to the comparison of using or without using the Single Line Freestanding Riser (SLFR), the operational design and installation conditions at FPU Gendalo-Gehem and located in the Makassar Strait using the six-strand wire rope with 0,115 meters outer diameter and 1.200 meters length will be fatigue life analysed. The FPU motion observation shows the highest Response Amplitude Operator (RAO) surge, sway, heave, roll, pitch, and yaw motion due to harsh environments are 0,615 m/m, 1,01x10-6 m/m, 1,048 m/m, 1,14x10-5 0/m, 2,23 0/m, and 9,08x10-8 0/m. It means that the amplitude response will always be smaller than the wave amplitude coming up. Taking into RAO motion calculation, the fatigue life on catenary mooring systems for following seas are 445 years in mooring line 1 and mooring line 8 with using SLFR while without using SLFR for 5.461 years in mooring line 1. The structure is still in safe condition because of the design safety factor about 300 years.
Pengaruh Brace Terhadap Kekuatan Kaki Struktur Helideck Dalam Menahan Beban Pendaratan Darurat Helikopter Anwar st; Ganding Sitepu; Muhammad Zubair Muis Alie
Jurnal Penelitian Enjiniring Vol 22 No 2 (2018)
Publisher : Center of Techonolgy (COT), Fakultas Teknik, Universitas Hasanuddin

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (764.233 KB) | DOI: 10.25042/jpe.112018.11

Abstract

Brace dan kaki struktur menjadi perhatian penting dalam merencanakan struktur helideck. Penelitian ini bertujuan menghitung kekuatan kaki struktur helideck terhdap variasi brace dalam menahan beban pedaratan darurat helikopter. Lokasi penelitian dilakukakn di laboratorium Struktur Departemen Perkapalan, Fakultas Teknik, Universitas Hasanuddin. Data yang digunakan adalah struktur helideck FSO Geudondong PT.Pertamina shipping Indonesia corporation. Perhitungan tegangan dan pemodelan struktur menggunakan software SACS, analisis pendaratan darurat helikopter dibagi menjadi tiga arah pendaratan yaitu arah transversal, logitudinal dan arah diagonal. Dalam mencari dimensi kaki yang optimal maka dilakukan pengurangan tebal dan diameter kaki struktur helideck sebesar 10%, 20%, 30% dan 40% dengan empat variasi model brace yaitu brace X, K, N dan Y. Hasil perhitungan tegangan maksimum yang bekerja terjadi pada posisi pendartan diagonal pada posisi D4 dengan tegangan kerja sebesar 49,86 N/mm2 dan nilai IR 0,45. Interaksi rasio (IR) yang terjadi pada kaki struktur pada pengurangan dimensi 40% sebesar (brace X = 0,99), (brace K =1,19), (brace N = 1,04), (brace Y = 1,03). Model brace yang paling lemah dalam menahan beban pendaratan darurat helikopter adalah model brace K dengan (IR = 1,19) dan model brace yang paling kuat adalah adalah brace X dengan IR = 0,99.
Sosialisasi Keselamatan Penyeberangan Wisata Pulau-Pulau Makassar Firman Husain; Juswan -; Taufiqur Rachman; Ashury -; Muhammad Zubair Muis Alie; Habibi Palippui
JURNAL TEPAT : Teknologi Terapan untuk Pengabdian Masyarakat Vol 4 No 2 (2021): Community Empowerment through Health Awareness in the New Normal
Publisher : Faculty of Engineering UNHAS

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.25042/jurnal_tepat.v4i2.229

Abstract

The increasing number of tourists visiting the islands in the Makassar City area is an exciting thing, especially for the perpetrators of inter-island crossing transportation. On the other hand, the safety aspect of this crossing must be a concern not only for tourists and the crossing transportation actors themselves, but the government and the general public must also provide input. Currently, there are about 25 boats operating on island tourism crossings, especially those operating at Panyua Pier. To increase awareness and safety of this sea crossing, a socialization activity on safety rules was carried out. The socialization was carried out directly in the room by presenting the crossing transportation actors. The participants were given material on safety rules for sea crossing transportation by the socialization team from the Department of Marine Engineering as part of the tridharma of higher education. Due to the ongoing pandemic conditions, the number of participants present in the room is limited. This socialization activity is aimed at the perpetrators of crossing transportation to tourist islands or in local terms called "palimbang" or people who cross passengers to the island using motor boats. Prior to the socialization, the committee gave a pretest to measure the level of knowledge of the 15 participants of the socialization. Posttest was also given after the socialization activity was carried out with the aim of knowing how well the participants' ability to absorb the socialization material was. From the results of the pretest to several questions, the result was an increase in knowledge of about 28.33% of the material given. At the end of this socialization activity, the participants were given life jackets as a safety tool, with the hope that the palimbangs will continue to use them while carrying out palimbang activities for their safety.
Residual Strength Analysisof Asymmetrically Damaged Ship Hull GirderUsing Beam Finite Element Method Alie, Muhammad Zubair Muis
Makara Journal of Technology Vol. 20, No. 1
Publisher : UI Scholars Hub

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Abstract

The objective of the present study is to analyze the residual strength of asymmetrically damaged ship hull girder under longitudinal bending. Beam Finite Element Method is used for the assessment of the residual strength of two single hull bulk carriers (Ship B1 and Ship B4) and a three-cargo-hold model of a single-side Panamax Bulk Carrier in hogging and sagging conditions. The Smith’s method is adopted and implemented into Beam Finite Element Method. An efficient solution procedure is applied; i.e. by assuming the cross section remains plane, the vertical bending moment is applied to the cross section and three-cargo-hold model. As a fundamental case, the damage is simply created by removing the elements from the cross section, neglecting any welding residual stress and initial imperfection. Also no crack extension is considered. The result obtained by Beam Finite Element Method so-called Beam-HULLST is compared to the progressive collapse analysis obtained by HULLST for the validation of the present work. Then, for the three-hold-model, the Beam-HULLST is used to investigate the effect of the rotation of the netral axis both intact and damage condition taking the one and five frame spaces into account.
Investigation of Ship Hull Girder Strength with Grounding Damage Alie, Muhammad Zubair Muis; Adiputra, Ristiyanto
Makara Journal of Technology Vol. 22, No. 2
Publisher : UI Scholars Hub

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Abstract

The objective of the present study is to investigate ship hull girder strength as a result of grounding damage upon longitudinal bending. A bulk carrier and tanker are analyzed and Smith’s Method is adopted and implemented in the analysis program. An efficient solution procedure is performed by assuming the cross-section remains plane and the vertical bending moment is applied to the cross section. As a fundamental case, the damage is simply created by removing the elements from the cross section. Welding residual stress, initial imperfections, and crack extensions are not considered. The grounding damage is made by two conditions, namely those are placed at the center part of the cross section and those located at an asymmetric position. To determine the ultimate strength, which includes the progressive collapse behavior of ship hull with damage, the simply supported scenario is imposed to the cross section and hogging and sagging conditions are taken into account. The results obtained for intact and damage conditions by the in-house program are compared with one another to observe the collapse behavior in advance.
Effects of Collision Damage on the Ultimate Strength of FPSO Vessels Alie, Muhammad Zubair Muis; Ramasari, Dian; Rachman, Taufiqur; Adiputra, Ristiyanto
Makara Journal of Technology Vol. 24, No. 1
Publisher : UI Scholars Hub

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Abstract

Floating production storage offloading (FPSO) vessels are movable offshore structures. These structures are designed with large dimensions, and their decks are loaded with several types of equipment. During collision damage, the hull and deck parts loaded with equipment are severely affected. Therefore, the ultimate strength of FPSO vessels should be thoroughly checked and evaluated. The objective of the present study is to analyze the ultimate strength of FPSO vessels against collision damage characterized by hogging and sagging under longitudinal bending. The cross section of an FPSO vessel is modeled with elements composed of stiffened and unstiffened plates. The vessel length is assumed to occupy one frame space. The ultimate strength of FPSO vessels against collision damage is determined by performing a numerical analysis under hogging and sagging conditions. Multipoint constraint is applied to both sides of the cross section, and the material properties are set to be constant. Collision damage is represented by the loss of element stiffness, and it represents the percentage of the ship’s depth. For the extent of transversal damage, B/16 is set to be constant. The minimum and maximum collision damages are taken as 10% and 60% of the ship’s depth, respectively. Numerical results show that the ultimate strength of FPSO vessels and their bending stiffness decrease under collision.