Analisis Kekuatan Buckling Pada Geladak Kapal Yang Mengalami Crack Menggunakan Elemen Shell-Solid

Darmawan, Muhammad Sidik (2026) Analisis Kekuatan Buckling Pada Geladak Kapal Yang Mengalami Crack Menggunakan Elemen Shell-Solid. Other thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Struktur geladak kapal tanker sangat rentan terhadap kegagalan tekuk (buckling), terutama saat menerima beban tekan aksial ekstrem akibat momen lentur memanjang kapal (sagging). Risiko kegagalan struktural ini meningkat secara signifikan jika terdapat cacat lokal berupa retakan (crack) akibat konsentrasi tegangan atau kelelahan material. Penelitian Tugas Akhir ini bertujuan menganalisis pengaruh variasi aspek rasio panel lokal terhadap kekuatan tekuk linear (Eigen buckling) dan perilaku non-linear buckling pada geladak kapal tanker yang mengalami cacat retak menggunakan Metode Elemen Hingga (MEH) dengn pemodelan shell-solid. Analisis diawali dengan pemodelan global tiga kompartemen ruang muat sepanjang 37,8 meter untuk mendapatkan beban tegangan normal geladak sebesar 131,34 MPa, yang kemudian dikonversikan menjadi gaya tekan aksial lokal input sebesar 866,844 kN pada area midship (Frame 77). Pengujian lokal diterapkan pada variasi rasio aspek panel (α=1,3,"dan " 5), yang setara dengan dimensi pelat 600 x 600 mm, 1800 x 600 mm, dan 3000 x 600 mm. Panjang crack ditetapkan konstan sebesar 150 mm dengan menyertakan initial imperfection geometri sebesar 2 mm berdasarkan ragam kegagalan literatur. Hasil Eigen buckling analysis menunjukkan beban kritis (P_cr) minimum pada Mode 1 berturut-turut sebesar 67,634 kN, 134,603 kN, dan 245,862 kN. Hal ini menandakan panel dengan aspek rasio terkecil (α=1) paling rentan mengalami tekuk linear karena berada jauh di bawah beban aktual kapal. Pada analisis non-linear, rasio tegangan normalized (σ/σ_Y) yang dicapai masing-masing variasi adalah sebesar 0,483 (α=1); 0,526 (α=3); dan 0,551 (α=5). Model pelat terkecil (600 x 600 mm) menghasilkan total deformasi bidang keluar (out-of-plane) tertinggi mencapai 31,906 mm dengan akumulasi regangan plastis maksimum yang memusat secara masif di sekitar area ujung retakan (crack tips). Kesimpulannya, variasi geometri rasio aspek panel dan keberadaan crack secara signifikan menurunkan batas stabilitas geladak kapal akibat tingginya konsentrasi tegangan lokal.
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The deck structure of oil tankers is highly vulnerable to buckling failure, particularly when subjected to extreme axial compressive loads caused by longitudinal bending moments (sagging). This structural vulnerability increases significantly in the presence of local defects such as cracks due to stress concentration or material fatigue. This final project aims to analyze the effect of variations in local panel aspect ratios on the linear buckling strength (Eigen buckling) and non-linear buckling behavior of cracked oil tanker deck structures using modeling shell-solid Finite Element Method (FEM). The analysis begins with the global modeling of three cargo hold compartments spanning 37.8 meters to obtain a deck normal stress of 131,34 MPa, which is then converted into a local input axial compressive force of 866,844 kN at the midship area (Frame 77). Local testing is applied to variations in panel aspect ratios (α=1,3,"and " 5), which correspond to plate dimensions of 600 x 600 mm, 1800 x 600 mm, and 3000 x 600 mm. The crack length is kept constant at 150 mm with a geometric initial imperfection of 2 mm derived from literature failure modes. The Eigen buckling analysis results show that the minimum critical loads (P_cr) for Mode 1 are 67,634 kN, 134,603 kN, and 245,862 kN, respectively. This indicates that the panel with the smallest aspect ratio (α=1) is the most vulnerable to linear buckling as it falls far below the ship's actual global forces. In the non-linear analysis, the ultimate normalized stress ratios (σ/σ_Y) achieved for each variation are 0.483 (α=1), 0.526 (α=3), and 0.551 (α=5). The 600 x 600 mm plate model produces the highest total out-of-plane deformation, reaching 31.906 mm, with the maximum plastic strain accumulation heavily localized around the crack tips. In conclusion, variations in panel aspect ratio geometry and the presence of a crack significantly reduce the ship deck's stability limits due to high local stress concentrations.

Item Type:	Thesis (Other)
Uncontrolled Keywords:	Buckling, Crack, Geladak Kapal, Metode Elemen Hingga, Shell-Solid Element, Buckling, Crack, Finite Element Method, Shell-Solid Element, Ship Deck
Subjects:	T Technology > TA Engineering (General). Civil engineering (General) > TA656.2 Buckling V Naval Science > VM Naval architecture. Shipbuilding. Marine engineering > VM156 Naval architecture
Divisions:	Faculty of Marine Technology (MARTECH) > Naval Architecture and Shipbuilding Engineering > 36201-(S1) Undergraduate Thesis
Depositing User:	Muhammad Sidik Darmawan
Date Deposited:	03 Aug 2026 08:15
Last Modified:	03 Aug 2026 08:15
URI:	http://repository.its.ac.id/id/eprint/141027

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