Prediksi Umur Kelelahan Struktur Kapal dengan Metode Spectral-Based Fatigue: Studi Kasus Kapal Ro-Ro 150 DWT

Siregar, Abdullah Taufiq Akbar (2026) Prediksi Umur Kelelahan Struktur Kapal dengan Metode Spectral-Based Fatigue: Studi Kasus Kapal Ro-Ro 150 DWT. Masters thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Kapal merupakan moda transportasi yang digunakan untuk mengangkut manusia, barang, atau keduanya. Kapal feri Ro-Ro (Roll-On/Roll-Off) double-ended merupakan jenis kapal yang didesain dengan bentuk kedua ujungnya yang identik, memungkinkan kapal untuk bergerak maju atau mundur tanpa perlu melakukan manuver. Umur struktur pada kapal (design lifetime) umumnya berkisar pada 20 tahun yang menjadi acuan utama dalam tahap desain. Menggunakan metode spectral based fatigue dalam memperkirakan umur kelelahan pada struktur kapal Ro-Ro 150 DWT. Dengan mempertimbangkan respons terhadap berbagai kondisi laut yang direpresentasikan dalam spektrum gelombang. Response Amplitude Operators (RAO) dihitung sebagai fungsi transfer yang menghubungkan beban gelombang dengan respons tegangan struktur. analisis spektral mencakup pendekatan kurun waktu pendek (short-term) menggunakan distribusi Rayleigh dan kurun waktu panjang (long-term) dengan distribusi Weibull untuk menentukan siklus kelelahan. Hasil penelitian menunjukkan bahwa karakteristik lingkungan perairan berpengaruh signifikan terhadap umur kelelahan struktur kapal. Di Selat Madura, kondisi gelombang relatif rendah, dengan tegangan ekstrem sebesar 124 MPa. Sebaliknya, di Selat Bali yang memiliki tinggi gelombang signifikan rata-rata 2.2 meter, tegangan ekstrem meningkat menjadi 237 MPa. Angka ini telah melampaui batas tegangan izin regulasi sebesar 165 MPa. Analisis pada titik kritis menunjukkan bahwa struktur knuckle 2 mengalami tegangan tertinggi. Nilai akumulasi kerusakan di Selat Madura pada knuckle 2 sebesar 0,320298, sementara di Selat Bali meningkat menjadi 0,601206. Umur kelelahan kapal yang beroperasi di Selat Madura mencapai 62,09 tahun, namun menurun sebesar 47,72% menjadi 32,46 tahun jika kapal beroperasi di Selat Bali.
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Ship is a mode of transportation used to carry passengers, cargo, or both. The double-ended Ro-Ro (Roll-On/Roll-Off) ferry is a type of vessel designed with identical bow and stern, allowing it to move forward or backward without the need for manoeuvring. The structural design lifetime of a ship is generally around 20 years and serves as a key reference in the design phase. Ships that have reached or exceeded this design lifetime require a comprehensive fatigue life assessment to ensure operational feasibility and safety. The spectral-based fatigue method is used to estimate the fatigue life of a 150 DWT Ro-Ro ship by considering its response to various sea conditions represented in the wave spectrum. Response Amplitude Operators (RAO) are calculated as transfer functions linking wave loads to structural stress responses. Spectral analysis includes short-term analysis using Rayleigh distribution and long-term analysis with Weibull distribution to determine fatigue cycles. The results of the study show that the characteristics of the marine environment significantly influence the fatigue life of ship structures. In the Madura Strait, wave conditions are relatively low, with extreme stresses reaching 124 MPa. Conversely, in the Bali Strait, which experiences significantly high waves averaging 2.2 meters, the extreme stress increases to 237 MPa. This value exceeds the regulatory permissible stress limit of 165 MPa. Analysis at the critical point indicates that the knuckle 2 structure experiences the highest stress. The accumulated damage value in the Madura Strait at knuckle 2 is 0.320298, while in the Bali Strait it increases to 0.601206. The fatigue life of ships operating in the Madura Strait reaches 62.09 years, but decreases by 47.72% to 32.46 years when operating in the Bali Strait.

Item Type:	Thesis (Masters)
Uncontrolled Keywords:	Spectral Fatigue Analysis, Umur Kelelahan, Kapal Ro-Ro, Spectral Fatigue Analysis, Fatigue Life, Ro-Ro Ship
Subjects:	V Naval Science > VM Naval architecture. Shipbuilding. Marine engineering > VM156 Naval architecture V Naval Science > VM Naval architecture. Shipbuilding. Marine engineering > VM161 Ships--Hydrodynamics V Naval Science > VM Naval architecture. Shipbuilding. Marine engineering > VM163 Hulls (Naval architecture) V Naval Science > VM Naval architecture. Shipbuilding. Marine engineering > VM381 Passenger ships
Divisions:	Faculty of Marine Technology (MARTECH) > Naval Architecture and Shipbuilding Engineering > 36101-(S2) Master Thesis
Depositing User:	Abdullah Taufiq Akbar Siregar
Date Deposited:	03 Feb 2026 02:15
Last Modified:	03 Feb 2026 02:15
URI:	http://repository.its.ac.id/id/eprint/131800

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