Studi Pengurangan Biaya Fabrikasi Struktur Dek Kapal dengan Hybrid GA
DOI:
https://doi.org/10.5614/jts.2019.26.3.11Keywords:
Biaya fabrikasi, struktur dek, hybrid GA, variabel diskrit, variabel kontinyuAbstract
Abstrak
Efek dari krisis ekonomi global adalah menurunnya aktivitas ekspor dan impor yang mempengaruhi terhadap menurunnya permintaan pembangunan kapal baru. Hal ini mengakibatkan galangan kapal melakukan efisiensi di seluruh aspek untuk tetap bertahan salah satunya dengan mengurangi biaya produksi sebuah kapal. Banyak studi terkait pengurangan berat dan biaya yang telah dilakukan dengan menggunakan metode optimasi. Penulis memilih struktur dek kapal yang terdiri dari pelat dan stiffener sebagai studi kasus. Pada studi ini, penulis mengoptimasi biaya fabrikasi struktur dek kapal yang terdiri dari biaya material dan biaya pengelasan dengan menggunakan hybrid algoritma genetika yang mengkombinasikan algoritma genetika dan metode optimasi lanjut. Algoritma genetika mengoptimasi variabel desain diskrit yang terdiri dan jumlah stiffener dan ukuran stiffener sedangkan metode optimasi lainnya mengoptimalkan variabel desain kontinyu yang terdiri dari jarak stiffener dan ketebalan pelat. Penulis mengambil bagian dari dek kapal tanker menjadi target optimasi yang kemudian dibandingkan hasilnya dengan data awal kapal. Hasil menunjukkan bahwa metode optimasi ini dapat mengurangi biaya fabrikasi dek kapal hingga 25 %.
Abstract
The impact of the global economic crisis is a decline in import and export activities resulting in a decrease in shipbuilding demand. Shipyard companies do efficiency in all aspects to survive which one of them is reduced production cost of a ship. Many studies for a lightweight and low-cost structure are being done which we also propose to solve the problem with the optimization method. We selected deck structure as a case study which is composed of plates and stiffeners. In this study, we optimized fabrication cost such the material cost and welding cost with a hybrid genetic algorithm (GA) which applied a genetic algorithm and other optimization methods. Genetic algorithm optimized the discrete design variables which are a number of stiffener and type of stiffener and other optimization methods optimized the continuous design variables which are stiffener spacing and plate thickness. We carried out part of deck structure of crude oil tanker, and the optimization results compared with data of existing ship. The result shows that the optimization method can decrease the fabrication cost of deck structure about 25 %.
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