Articles

Found 2 Documents
Search

Residual Strength Analysisof Asymmetrically Damaged Ship Hull GirderUsing Beam Finite Element Method Muis Alie, Muhammad Zubair
Makara Journal of Technology Vol 20, No 1 (2016)
Publisher : Directorate of Research and Community Services, Universitas Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (733.696 KB) | DOI: 10.7454/mst.v20i1.3252

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 isused 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 Carrierin 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 axisboth intact and damage condition taking the one and five frame spaces into account. 
Fatigue Analysis of Catenary Mooring System due to Harsh Environment in Head Seas Assidiq, Fuad Mahfud; Paroka, Daeng; Muis Alie, Muhammad Zubair; Klara, Syerly
EPI International Journal of Engineering Vol 1 No 1 (2018): Volume 1 Number 1, February 2018
Publisher : Center of Techonolgy (COT), Engineering Faculty, Hasanuddin University

Show Abstract | Download Original | Original Source | Check in Google Scholar

Abstract

The Floating Production Unit (FPU) is a floating gas production barge that is moored by catenary mooring system to the seabed. In the operation, Floating Production Unit (FPU) will get dynamic loads such as ocean waves, ocean currents, and winds on the mooring line structure periodically. This may cause damage to mooring line structures which effect to the operational structure performance. The aim of the present study is to discuss fatigue life on catenary mooring system. The model studied 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. The dimensions of mooring line type six-strand wire rope are 0,115 meters outer diameter and 1.200 meters length will be fatigue life analyzed. The FPU motion observation in heading 1800  (head seas) shows the highest Response Amplitude Operator (RAO) surge, sway, heave, roll, pitch, and yaw motion due to harsh environments with Hs = 4,0 meters and T = 7,7 sec are 0,615 m/m; 9,354x10-7 m/m; 1,048 m/m; 18,423x10-6 0/m; 2,225 0/m; and 12,671x10-8 0/m. It means that the amplitude response will always be smaller than the wave amplitude coming up. Another thing happened when using SLFR has longer frequency about 0,207 rad/sec than without using SLFR. Taking into RAO motion calculation, the fatigue life on catenary mooring systems for head seas are 412 years in mooring line 4 and mooring line 5 with using SLFR while without using SLFR for 6.636 years in mooring line 5. The structure is still in safe condition because of the design safety factor about 300 years.