An integrated method for block assembly sequence planning in shipbuilding

Many efforts in the past have been made to find more efficient methods for assembly sequence planning in machining area. While few researches reported in other area such as block assembly in shipbuilding industry. In general, a ship hull is built with hundreds of different blocks, most of which are complicated in structure and different from each other in assembly planning. Additionally, there may be a large number of feasible assembly sequences for any block. A better sequence can help to reduce the cost and time of the manufacture. Therefore, it is necessary to seek out the optimal sequence from all feasible ones. Currently, the assembly sequences are determined manually by some process engineers. Consequently, it is becoming a time-consuming task and cannot make the assembly plan consistent to improve productivity. In this paper, a methodology-integrated case-based reasoning and constraints-based reasoning is proposed to improve the assembly planning for complicated products. Besides, genetic algorithm is designed to evaluate and select the optimal sequence automatically from the reference ones. The validity of the method is tested using real blocks, and the results show that it can facilitate the optimal assembly sequences generation.