Automatic Design Method and Application in Complex Ship Block Lifting

Abstract

The traditional block lifting schemes often give rise to a host of problems such as the complexity of the lifting process, low degree of automation, and lack of theoretical guidance. To overcome the deficiencies, the authors of this paper have developed an automatic design system for the complex block lifting. Tribon is adopted as the data extraction method to identify the feature area of a block so as to lay out the lifting lugs properly and efficiently. Besides, Matlab is employed to analyze the stress on lifting wires and 3ds Max to simulate the block lifting process. In this way, the potential problems about mechanics and interference between the block and wires can be forecasted so as to enable the designers to improve the lifting scheme and ensure a safer and more reliable design. 1. Introduction Block lifting operation is a crucial process in shipbuilding since it determines the efficiency of the hull construction as well as the quality of the ship. The traditional artificial block lifting schemes often entail a host of problems such as the complexity of the lifting process, low degree of automationand lack of theoretical guidance. in recent years, scholars have studied the block lifting technologies for several types of ships including Very Large crude carrier (VLcc) and the container vessel. After analyzing the features of block lifting operation and the lifting environment, Li et al. (2013) summarized the principles and requirements of block lifting design, built models for the object to be lifted for the lifting equipment as well, designed an automatic layout algorithm for block lifting scheme and developed a design system for ship block lifting. Li et al. (2014) rebuilt the finite element model under ANSYS environment based on the extracted data of blocks. The calculation results can serve as a guidance for the design of structural reinforcement, which can save materials and reduce workload. In terms of the block lifting technologies used in the building of a 3500 TEU container vessel, Zhang (2010) studied on the lifting technologies employed in lifting some typical blocks such as the stern, broadside, and engine room. Based on the analysis and study on hull assembly method, Yu (2014) took use of computer to successfully simulate the process of hull assembly and save the relevant process information about the hull before shipbuilding. Kim et al. (2005) developed the virtual assembly simulation system for shipbuilding, which can simulate the operation of cranes and the installation of blocks in a virtual shipyard and evaluate the operations. Miura (2011) adopted the three-dimensional computer Aided Design (cAD) to develop a simulation system for block lifting and then he illustrated the features and functions of the system and stressed the importance of threedimensional model used in the process. Takola et al. (2013) established a mathematical model to analyze the constraint conditions in the block lifting process so as to optimize the lifting scheme and improve the efficiency of lifting operations. By applying the theory of combined discrete event and discrete time, Cha J.H. developed an integrated simulation framework for block lifting and erection process (Cha et al. 2010; Cha & Roh 2010). KuN. developed a crane system consists of several crane types, a scenario manager capable of creating and editing lifting process for multibody dynamics-based simulation is proposed (Ku et al. 2014a, 2014b). This study focuses on the complex ship block lifting with an attempt to build a system integrating the design of the complex block lifting scheme, the analysis on the mechanical characteristics in the lifting process and the simulation design of the block lifting operation together (Fig. 1).