Proceedings of the Thirty-second (2022) International Ocean and Polar Engineering Conference
Shanghai, China, June 5–10, 2022
Copyright © 2022 by the International Society of Offshore and Polar Engineers (ISOPE)
ISBN 978-1-880653-81-4; ISSN 1098-6189

www.isope.org

A Study on Key Technologies of Optimization Design for CorrugatedBulkhead of Bulk Carrier
Pingshu Li, Yacong Liu, Yamin Tang, Jiameng Wu
Marine Design & Research Institute of China
Shanghai, China

Carrier, it is very necessary to carry out optimization design forcorrugated bulkhead, with the objective of weight-lightening except
strength-fulfilling.
In CSR rule, the requirements about corrugated bulkhead structure arequite complicated. Several calculations, such as lateral pressure
requirement bending strength shear strength and buckling strength andso on, are needed to be carried out. Several load cases are needed to beconsidered and their correspondent loads to be calculated, and dynamic
loads need to adopt equivalent design wave method(IACS,2020).
Therefore, the optimization for corrugated bulkhead of Bulk Carrierneeds a good and effective tool and method.
The authors have carried out studies on the method of optimization
design for corrugated bulkhead of Bulk Carrier and have developed
software. In this paper, several key technologies involved in the method,such as optimization model, load calculation method, design load
application method and scantling optimization calculation method, aremainly described.

ABSTRACTIn this paper, several key technologies about optimization design for
corrugated bulkhead of bulk carrier are studied based on prescriptive
strength assessment of CSR rule. Firstly, a study on the optimization
mathematical function is carried out. And a model is created with theobjective function being the minimum nominal thickness of corrugation.
Then calculation methods are studied about the loads for prescriptive
strength assessment of corrugated Bulkhead of Bulk Carrier. The paper
investigates definition of the upper surface of dry bulk cargo for cargohold and the calculation method about the reference point for dynamic
liquid pressure in heavy ballast hold. And then it summarizes some of
their commonness and characteristics. By several actual calculations,the researchers find out some characteristics about the distribution ofprescriptive strength assessment load of bulk carrier corrugatedbulkhead. And then, methods about the application of corrugatedbulkhead loads are explored. Three methods, which are extremum
method, static block method and dynamic block method, are brought
forward, and the method that load grads being calculated based on therequirement of lateral pressure is proposed. Comparison research iscarried out, and the result proves that from the vision of weightlightening design, the dynamic block method is the best. Finally, thepaper investigates optimization calculation methods about the scantlingof corrugation. The researchers create an optimization calculation
process and method based on bending strength requirement. And
several strategies applied in thickening of corrugation have been
researched. Based on the comparison result, it has been proved that thebest strategy is to thicken the lower corrugation end only.

OPTIMIZATIONMODEL
Objective in this method is the nominal thickness of corrugation.
Nominal thickness is the thickness when transferring the area of unit
length of corrugation to an equivalent length of plane, as shown in Fig.
1.
Design variables are the three characteristic parameters of a corrugation,
which are depth of corrugation(dcg), width of flange(bf) and corrugation
angle(θ).
Constraint conditions are the prescriptive strength requirements of CSR
rule, including minimum thickness requirement, lateral pressure
requirement, shear strength, bending strength, buckling strength andplating division requirement, etc.
Design responses are the thickness of each web and flange in upper,
middle and lower parts of a corrugation. According to the plating
division requirement, the vertical division is shown in Fig.2. For coldhot formed type corrugation, the thickness of web and flange are thesame, the larger requirement value between them is to be the response.
For built-up type corrugation, the thickness between web and flange

KEY WORDS: Corrugated bulkhead; optimization design; bulkcarrier; CSRINTRODUCTION
Normally, corrugated bulkheads are adopted in cargo hold area of BulkCarrier. Being a significant part of the whole structure design of Bulk3864