ABSTRACT

Corrugated bulkhead has been adopted for cargo tank bulkheads of commercial vessels such as bulk carriers, product oil carriers and chemical tankers. It is considered that corrugated bulkhead is a preferred structural solution, compared to the flat stiffened bulkhead, due to several advantages such as lower mass, easier maintenance and smaller corrosion problems. Many researches to find the optimum shape of corrugated bulkhead have been mostly carried out for bulk carriers. Compared to corrugated bulkheads of bulk carriers, ones of chemical tankers are more complicated since they are composed of transverse and longitudinal bulkheads, and they are made of higher priced materials. The purpose of this study is the development of minimum weight design method for corrugated bulkhead of chemical tankers. Evolution strategy is applied as an optimization technique. It has been verified from many researches that evolution strategy searches global optimum point prominently by using multi-individual searching technique. Multi-individual searching methods need excessive time if they connect to 3-D finite element model for repetitive structural analyses. In order to resolve this issue, 2-D beam element connected to the deck and the lower stool is substituted for a corrugated structure in this study.

INTRODUCTION

Corrugated bulkhead is used as the bulkhead of cargo hold compartment of the some kinds of vessels for having easier maintenance, easier loading and unloading and more flexible shape in shrinkage and expansion by thermal load compared to the flat stiffened bulkhead. Corrugated bulkheads can be commonly seen in bulk carriers, product oil carriers and chemical tankers.

A lot of researches on optimal design of corrugated bulkhead have been mostly conducted with bulk carriers. Yim et al. (1987), Yum (1990) and Lee et al. (2001) performed the researches focusing on optimization method itself and Shin et al. (2003) performed optimal design of corrugated bulkhead of bulk carrier considering both optimization method and workability to make it applicable to the field work.

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