Analisis Fatigue Life Konstruksi Car Deck Kapal Ferry Ro Ro Terhadap Pembebanan Bervariasi

Baharullah, Amam (2025) Analisis Fatigue Life Konstruksi Car Deck Kapal Ferry Ro Ro Terhadap Pembebanan Bervariasi. Masters thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Analisis fatigue life menjadi salah satu aspek penting dalam pembangunan kapal, namun sering kali kurang diperhatikan sehingga umur kontruksi sebuah kapal tidak dapat diprediksi secara akurat. Penelitian ini memfokuskan pada umur kelelahan (fatigue life) struktur car deck kapal ferry jenis roll-on/roll-off (ro-ro) yang terjadi deformasi. Permasalahan yang diangkat mencakup penentuan nilai stress tertinggi, identifikasi lokasi stress tertinggi, optimasi desain guna mengurangi nilai stress, serta estimasi fatigue life dari struktur car deck. Proses perhitungan dilakukan sebagai acuan menentukan umur cardeck kapal mendatang. Penelitian ini menggunakan Finite Element Method (FEM) dalam analisis dan perhitungan fatigue life menggunakan metode pendekatan sonderberg. Tahapan yang dalam penelitian ini dimulai dari menghitung distribusi berat dan bouyancy kesuluruhan dari kapal, selanjutnya dari nilai distribusi beban tersebut didapatkan nilai kekuatan kapal. Hasil analisis menunjukkan nilai tegangan tertinggi terjadi pada kondisi muatan berlebih dan gelombang hagging sebesar 1065,70 MPa, disusul oleh kondisi muatan normal gelombang hagging sebesar 938,63 MPa, muatan normal gelombang sagging sebesar 886,47 MPa, dan muatan berlebih gelombang sagging sebesar 769,16 MPa. Lokasi tegangan maksimum sebagian besar terjadi pada pertemuan antara dinding miring dan dinding dalam cardeck di Frame 12 (P/S), serta menyebar di area cardeck pada kondisi ekstrem. Optimasi desain dilakukan melalui penambahan 10 buah girder T350x150x20 mm sepanjang area cardeck Hasil optimasi berhasil menurunkan nilai tegangan maksimum menjadi 324,6 MPa, atau penurunan sebesar 69,5% dibandingkan kondisi sebelum optimasi. Dari perhitungan memiliki fatigue life sebesar 103,3 tahun (muatan normal–sagging), 82,4 tahun (muatan normal–hagging), 100,3 tahun (overload–sagging), dan 77,4 tahun (overload–hagging). Setelah dilakukan optimasi, fatigue life pada kondisi paling kritis (overload–hagging) meningkat menjadi 105,1 tahun. Hasil ini menunjukkan bahwa optimasi desain mampu meningkatkan ketahanan struktur secara signifikan terhadap beban.
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In development of ship, fatigue life is one of analisist that often not undestood. So that caused the life construction of ship unknown. This study focuses on analyzing the fatigue life of the car deck on a roll-on/roll-off (Ro-Ro) ferry, which has experienced structural deformation. The researcher aims to identify the maximum stress values, the locations where these stresses occur, the causes of the deformation, and the estimated fatigue life of the car deck on a Ro-Ro passenger ship. The goal of this calculation is to determine the expected service life of the car deck structure, which can then serve as a reference for assessing similar structures in the future. The analysis applies the finite element method combined with a fatigue life estimation using the Soderberg approach. The step of this research is started from calculating weight and bouyancy distribution the whole of ship, then the number of ship longitudinal strength will be obtained from the result of load distribution. The analysis indicates that the maximum stress appears under the overloaded condition combined with a hogging wave, reaching a value of 1065.70 MPa. This is followed by the normal load–hogging condition at 938.63 MPa, the normal load–sagging condition at 886.47 MPa, and the overloaded–sagging condition at 769.16 MPa. The analysis identifies the highest stress concentration at the junction between the inclined wall and the inner wall of the car deck at Frame 12 (P/S), with the stress spreading across the deck area during extreme loading conditions. The design optimization adds 10 T350x150x20 mm girders along the car deck area. This modification successfully reduces the maximum stress to 324.6 MPa, a 69.5% decrease from the pre-optimization state. The calculated fatigue lives are 103.3 years (normal load–sagging), 82.4 years (normal load–hogging), 100.3 years (overload–sagging), and 77.4 years (overload–hogging). After optimization, the fatigue life under the most critical condition (overload–hogging) increases to 105.1 years. These results demonstrate that the optimized design significantly enhances the structural resistance against loads.

Item Type:	Thesis (Masters)
Uncontrolled Keywords:	Car Deck, Fatigue Life, Finite Element Method, Passeger Ship, Ships Longutudinal Strenght
Subjects:	V Naval Science > VM Naval architecture. Shipbuilding. Marine engineering > VM163 Hulls (Naval architecture) V Naval Science > VM Naval architecture. Shipbuilding. Marine engineering > VM293 Shipping--Indonesia--Safety measures V Naval Science > VM Naval architecture. Shipbuilding. Marine engineering > VM381 Passenger ships
Divisions:	Faculty of Marine Technology (MARTECH) > Marine Engineering > 36101-(S2) Master Theses
Depositing User:	Amam Baharullah
Date Deposited:	05 Aug 2025 04:45
Last Modified:	05 Aug 2025 04:45
URI:	http://repository.its.ac.id/id/eprint/127430

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