Structural Integrity Assessment of Independent Type-C Cylindrical Tanks Using Finite Element Analysis: Comparative Study Using Stainless Steel and Aluminum Alloy

Abstract

The International Maritime Organization stipulates that greenhouse gas emissions from ships should be reduced by at least 50% relative to the amount observed in 2008. Consequently, the demand for liquefied natural gas (LNG)-fueled ships has increased significantly. Therefore, an independent type-C cylindrical tank, which is typically applied as an LNG fuel tank, should be investigated. In this study, structural integrity assessments using finite element analysis are performed on C-type LNG fuel tanks for a sea-cleaning vessel. In addition, the applicability of stainless steel and aluminum alloys is evaluated for LNG tank construction. Structural analyses and fatigue limit evaluations, including heat transfer analyses for the tank based on IGC code requirements, are performed, and the results are compared. The results of this study are expected to facilitate the selection of materials used for independent type-C tanks.

Comparative FEM Analysis of Vacuum and Perlite Insulation Techniques on the Structural Integrity of Independent Type C Liquefied Natural Gas Tank

“…High-cycle fatigue is usually studied under standard operating conditions, while low-cycle fatigue is studied under more severe circumstances, such as during bunkering. Park et al [23] performed a full structural assessment of an LNG tank considering both low and high-cycle fatigue included. While they used FEM for the structural assessment, fatigue analysis was performed using an analytical approach to calculate damage accumulation, and the Von Mises stress was used as a criterion for determining the number of cycles until crack initiation.…”

“…where f is the reference allowable stress expressed as an f = min (R m /A, R e /B), A and B are coefficients determined by the steel grade and are equal to A = 3.5 and B = 1.5 for the selected 304L steel. As can be seen from Equation ( 6), the sum of local bending, membrane, and secondary stress (σ m + σ b + σ g ≤ 3f ) is the most critical condition since stress is generated due to complex load cases, thus consisting of all the combined loads, Park et al [23].…”

Desain Liquified Natural Gas Bunkering Vessel (LNG BV) untuk Melayani Kapal Berbahan Bakar LNG yang Melewati ALKI II

“…Independent tank adalah tangki yang strukturnya terpisah dengan lambung kapal dan tidak menjadi struktur kekuatan kapal. IMO Type C Tank merupakan salah satu jenis independent tank pressure vessel didesain untuk menahan vapor pressure tinggi, dengan demikian dapat mengurangi risiko kebocoran pada umur pakai tangki [3] dan juga dipilih karena desain yang simple, murah, dan berkeamanan tinggi.…”

“…Setelah dilakukan perhitungan dan analisa ini maka didapatkan kesimpulan dari penelitian ini adalah sebagai berikut: (1) Tinjauan daerah ALKI II didapatkan konsumen kapal LNG bunkering vessel pada ALKI II merupakan kapal bulk carrier tipe panamax sejumlah 12 kapal per hari dengan asumsi kapasitas tangki masing-masing kapal sebesar 700 m 3 6) Desain 3D dan animasi berbasis aplikasi dari LNG bunkering vessel dapat dilihat pada Gambar 11. (7) Hasil perhitungan ekonomis didapatkan biaya pembangunan LNG bunkering vessel sebesar 29.304.334,82 Dolar AS.…”