Maghriza, Revy (2020) Analisis Umur Kelelahan Sistem Tambat Akibat Pengaruh Ketidaksimetrisan Konfigurasi Mooring System 4x1 Pada Single Point Mooring. Other thesis, Institut Teknologi Sepuluh Nopember.
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Abstract
Tugas Akhir ini menjelaskan tentang analisis umur kelelahan anchor chain pada single point mooring kondisi stand alone dengan membandingkan dua konfigurasi mooring system 4x1 asimetris dan simetris untuk mengetahui apakah kedua konfigurasi mooring system tersebut aman selama masa operasi dan untuk mengetahui bagaimana pengaruh ketidaksimetrisan konfigurasi mooring system pada fatigue life anchor chain terkait panjang mooring line, pretension, dan sudut sebarnya. Analisis ditinjau pada kondisi pembebanan lingkungan Ultimate Limit State (ULS) dan Fatigue Limit State (FLS) berdasarkan code API RP 2 SK menggunakan Orcaflex. Kondisi pembebanan lingkungan ULS digunakan untuk mengetahui tension maksimum anchor chain dan offset maksimum SPM sedangkan kondisi pembebanan lingkungan FLS digunakan untuk mengetahui umur kelelahan anchor chain menggunakan metode rainflow counting dengan kurva T-N. Pada kondisi ULS, konfigurasi simetris lebih mampu menahan beban lingkungan arah 0 derajat dan 180 derajat karena hasil tension maksimum dan offset maksimum yang lebih kecil dari konfigurasi asimetris yaitu 730.51 kN (heading 0 derajat) dan 762.23 kN (heading 180 derajat) untuk tension maksimum dan 5.94 m (heading 0 derajat dan 180 derajat) untuk offset maksimum. Sedangkan konfigurasi asimetris lebih mampu menahan beban lingkungan pada arah 90 derajat dan 270 derajat karena hasil tension maksimum dan offset maksimum yang lebih kecil dari konfigurasi simetris yaitu 53.31 kN (heading 90 derajat) dan 47.87 kN (heading 270 derajat) untuk tension maksimum dan 4.95 m (heading 90 derajat) dan 4.72 m (heading 270 derajat) untuk offset maksimum. Pada kondisi FLS, konfigurasi asimetris memiliki umur kelelahan minimum anchor chain yang lebih panjang yaitu sebesar 291 tahun dengan umur desain sebesar 97 tahun daripada konfigurasi simetris yang memiliki umur kelelahan minimum anhcor chain sebesar 207 tahun dengan umur desain sebesar 69 tahun. Hasil ini menunjukkan bahwa kedua konfigurasi mooring system dapat dinyatakan aman untuk beroperasi karena umur desainnya melampaui umur layanan operasi yang diharapkan yaotu 20 tahun. Hasil ini juga menunjukkan pengaruh ketidaksimetrisan konfigurasi mooring system karena beberapa faktor yaitu sudut sebar mooring line, panjang mooring line, dan pretension mooring line.
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The final project explains the fatigue life analysis of anchor chain on single point mooring in stand-alone conditions by comparing the asymmetric and symmetric 4x1 mooring system configurations to find out whether the two mooring system configurations are safe during the operating period and to find out how the influence of the asymmetric mooring system configuration on fatigue life of the anchor chain which is related to the length of the mooring line, pretension, and spread angle. The analysis was reviewed in terms of the environmental conditions of Ultimate Limit State (ULS) and Fatigue Limit State (FLS) based on the API RP 2 SK code using Orcaflex software. ULS environmental loading condition is used to determine the maximum tension of anchor chains and maximum offset of SPM while the FLS environmental loading condition is used to determine the fatigue life of the anchor chains using the rainflow counting method with a T-N curve. In the ULS condition, the symmetric configuration is better able to withstand environmental loads in the heading of 0 degrees and 180 degrees because the results of maximum tension and maximum offset are smaller than the asymmetric configuration of 730.51 kN (heading of 0 degrees) and 762.23 kN (heading of 180 degrees) for maximum tension and 5.94 m (heading of 0 degrees and 180 degrees) for maximum offset. While the asymmetric configuration is better able to withstand environmental loads in the heading of 90 degrees and 270 degrees because the results of maximum tension and maximum offset are smaller than the symmetric configuration of 53.31 kN (heading of 90 degrees) and 47.87 kN (heading of 270 degrees) for maximum tension and 4.95 m (heading of 90 degrees) and 4.72 m (heading of 270 degrees) for maximum offset. In the FLS condition, the asymmetric configuration has a longer minimum fatigue life of anchor chain which is 291 years with a design life of 97 years than the symmetric configuration which has a minimum fatigue life of anchor chain which is 207 years with a design life of 69 years. these results indicate that both mooring system configurations can be declared safe to operate because the design life of them exceeds the expected service life of 20 years. These results also indicate the influence of asymmetric mooring system configuration because of several factors, namely the spread angle of the mooring line, the length of the mooring line, and the pretension of the mooring line.
| Item Type: | Thesis (Other) |
|---|---|
| Uncontrolled Keywords: | Anchor chain, tension, T-N curve, fatigue life, rainflow method, rantai jangkar, tarikan, kurva T-N, umur kelelahan, metode rainflow |
| Subjects: | T Technology > TC Hydraulic engineering. Ocean engineering > TC1680 Offshore structures |
| Divisions: | Faculty of Marine Technology (MARTECH) > Ocean Engineering > 38201-(S1) Undergraduate Thesis |
| Depositing User: | Revy Maghriza |
| Date Deposited: | 12 Aug 2020 08:57 |
| Last Modified: | 27 May 2023 04:41 |
| URI: | http://repository.its.ac.id/id/eprint/77743 |
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