Studi Penentuan Safety Factor Dengan Analisa Keandalan Pada Kapal Tanker

Bararah, Kiramim (2024) Studi Penentuan Safety Factor Dengan Analisa Keandalan Pada Kapal Tanker. Other thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Proses penetuan safety factor pada proses desain kapal pada umumnya cenderung menggunakan pendekatan deterministik atau menggunakan standar yang ditentukan oleh class society, proses ini terkadang menyebabkan desain kapal cenderung sama rata dan tidak mempertimbangkan kondisi lingkungan operasional serta material kapal. Untuk memperbaiki hal itu digunakan metode pendekatan probabilistik yang ikut mempertimbangkan faktor ketidakpastian pada kondisi pembebanan dan kekuatan material pada proses penentuan safety factor kapal. Untuk mendapatkan nilai pembebanan (load), pada penelitan ini setiap kapal tanker dengan variasi panjang LOA 90 m, 120 m dan 150 m diberikan simulasi pembebanan pada kondisi perairan dengan ketinggian significant wave (Hs) 1.5 m, 3.5 m, 5.5 m dan 7.5 m menggunakan persamaan JONSWAP dengan nilai gamma 1.5 sesuai standar IACS 34 rev 2 untuk kondisi perairan laut atlantik utara. Untuk pendapatkan nilai kekuatan (strength) dilakukan pengujian tarik pada material standar BKI yaitu baja ASTM 131/marine grade A. dari simulasi beban gelombang didapatkan nilai covariant dari maksimum pitch wave bending moment untuk kapal 90 m pada Hs 1.5 m, 3.5 m, 5.5 m, 7.5 m adalah 44,95%. Untuk kapal 120 m adalah 58.17%, dan untuk kapal 150 m 70.68%. sedangkan nilai mean, standar deviation dan covariant yield stress material adalah 292.66 N/mm2, 6.24 N/mm2, dan covariant 2.13%. dari nilai-nilai tersebut didapatkan nilai safety factor kapal 90 m untuk keandalan 99,99%, 97,5%, 95%, 92,5%, dan 90% adalah 2.57, 1.86, 1.72, 1.63, dan 1.57. untuk kapal 120 m adalah 3.08, 2.11, 1.93, 1.83 dan 1.74. dan untuk kapal 150 m adalah 2.83, 1.88, 1.72, 1.6 dan 1.52. dimana hal ini menunjukkan bahwa safety factor untuk keandalan di atas 90% rata-rata lebih tinggi dari safety factor yang ditetapkan BKI, kecuali untuk kapal 90 m dengan tingkat keandalan 90% - 92,5%. Safety factor BKI yang dijadikan nilai pembanding bernilai 1,34, yang didapat dari 235 N/mm2 dibagi 175 N/mm2.
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The process of determining the safety factor in ship design generally tends to use a deterministic approach or standards set by class societies. This process often results in uniform ship designs that do not consider operational environmental conditions and ship material properties. To address this, a probabilistic approach is used, taking into account the uncertainty factors in load conditions and material strength during the determination of the ship's safety factor. In this study, tanker ships with varying lengths of LOA 90 m, 120 m, and 150 m were subjected to load simulations under sea conditions with significant wave heights (Hs) of 1.5 m, 3.5 m, 5.5 m, and 7.5 m using the JONSWAP equation with a gamma value of 1.5, according to the IACS 34 rev 2 standards for North Atlantic sea conditions. To determine the strength values, tensile tests were conducted on BKI standard materials, specifically ASTM 131/marine grade A steel. From the wave load simulations, the mean, standard deviation, and coefficient of variation of the maximum pitch wave bending moment for a 90 m ship at Hs 1.5 m, 3.5 m, 5.5 m, and 7.5 m were found to be 173 meganewtons (MN), 77 MN, and a coefficient of variation of 44.95%. For the 120 m ship, the values were 450 MN, 262 MN, and a coefficient of variation of 58.17%. For the 150 m ship, the values were 820 MN, 580 MN, and a coefficient of variation of 70.68%. Meanwhile, the mean, standard deviation, and coefficient of variation for the material yield stress were 292.66 MPa, 6.24 MPa, and 2.13%, respectively. From these values, the safety factor for a 90 m ship with reliability levels of 99.99%, 97.5%, 95%, 92.5%, and 90% were found to be 2.57, 1.86, 1.72, 1.63, and 1.57, respectively. For the 120 m ship, the values were 3.08, 2.11, 1.93, 1.83, and 1.74. For the 150 m ship, the values were 2.83, 1.88, 1.72, 1.6, and 1.52. This indicates that the safety factors for reliability levels above 90% are on average higher than the BKI-specified safety factor of 1.3, which is derived from 235/175

Item Type:	Thesis (Other)
Uncontrolled Keywords:	Simulasi Monte Carlo, Analisis Keandalan, Faktor Keselamatan, Beban Gelombang, Momen Bending Monte Carlo Simulation, Reliability analysis, Safety Factors, Wave Loads, Bending Moments
Subjects:	V Naval Science > VM Naval architecture. Shipbuilding. Marine engineering > VM156 Naval architecture V Naval Science > VM Naval architecture. Shipbuilding. Marine engineering > VM163 Hulls (Naval architecture) V Naval Science > VM Naval architecture. Shipbuilding. Marine engineering > VM297 Ships Designs and drawings
Divisions:	Faculty of Marine Technology (MARTECH) > Naval Architecture and Shipbuilding Engineering > 36201-(S1) Undergraduate Thesis
Depositing User:	Kiramim Bararah
Date Deposited:	04 Sep 2024 06:19
Last Modified:	04 Sep 2024 06:19
URI:	http://repository.its.ac.id/id/eprint/113036

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