Modelling and optimisation of hull erection process

Abstract

Due to the low efficiency of hull erection, this paper applies fuzzy-timed place Petri net (P-FTPN) to model the process of hull construction. Triangular Fuzzy Number (TFN) is utilised to denote the uncertain duration. A rule of setting dummy place and a reformative Minkowski subtraction are presented. According to the model, the low efficiency attributes to the time-consuming disequilibrium of each parallel branch and the complicated interrelations within tasks. Thus, we adjust the Orientation Block, eliminate the Hatch Coaming Blocks and combine them with corresponding Compartment Blocks, repartition the complicated Bow Blocks and reduce the construction difficulty. On this basis, modularisation building and preliminary group erection are applied for partial blocks. The parallel erection strategy is achieved on the whole from serial erection strategy. The result shows the efficiency has been enhanced greatly. Finally, whether a given construction state is in rational construction scheme(s) can be identified immediately from the Reasonable Marking Graph (RMG) of the model. Then, the dynamic supervisory control to the hull erection process can be realised.

Keywords:

• hull erection
• modelling
• P-FTPN
• optimisation
• efficiency

Acknowledgement

Two earlier versions of this paper were presented as ‘Zhang, Y.Q., Xu, K.L. and Hong, X.D., 2009. Modeling and optimization of hull building process based on P-TPN. In: Proceedings of the 2009 international joint conference on computational sciences and optimization – volume 02, 24–26 April 2009 Sanya, Hainan Island. Piscataway, NJ: IEEE, 989–992’ and ‘Zhang, Y.Q., et al., 2009. Simulation and optimization of hull erection based on P-FTPN. In: Proceedings 2009 IEEE 16th international conference on industrial engineering and engineering management, 21–23 October Beijing. Piscataway, NJ: IEEE, 1860–1864’.