Analisis Perbandingan Sambungan Pengelasan dan Knock Down pada Bulbous Bow Kapal Ferry Ro-Ro 2000 GT Terhadap Fatigue Life Menggunakan Metode Elemen Hingga

Abstract

A shipyard company constructed a 2000GT Ro-ro ferry in 2021. The ship operates on the route from
Tanjung Perak port to Lembar NTB port via the Flores Sea along the northern coast of Bali Island. During its sailing
activities serving passengers, the owner intends to add a bulbous bow to the ship to reduce resistance and improve the
efficiency of the ship's main engine. The installation plan includes insights for using a knock-down joint for the bulbous
bow. Therefore, this research simulates the use of knock-down joint design and compares it with welded joints to
estimate its fatigue life. The simulation process employs Ansys Workbench and includes variations of welded joints,
bolted joints, and stud welding. The simulations are conducted by applying loading due to hydrostatic pressure and
variations of stress caused by slamming loads. The research results estimate the fatigue life through calculations based
on the ABS Guide for Fatigue Assessment of Offshore Structures (2020), with the longest estimated life being 28.9
years and the shortest being 3.67 years. So, the implementation of knockdown joints in the installation of the bulbous
bow is less effective because, at high slamming intensity, the fatigue life value of the knockdown joints does not exceed
the threshold set by ABS.