Optimization of a line-cutting procedure for ship hull construction by an effective tabu search

A problem of a line-cutting procedure is discussed for ship hull construction. This procedure includes five steps: stock arrangement, piece arrangement, marking, cutting and special processes, and delivering the work. The line-cutting procedure will be optimized when two objectives are considered: minimizing the total trim loss and keeping the working efficiency of the cutting procedure. The developed way for the discussed problem is to optimize the stock arrangement associated with a proposed rule-based piece arrangement where the former is optimized for minimizing the total trim loss and the latter for keeping the working efficiency. A tabu search is chosen for the optimization of stock arrangement. In addition, two proposed replacement moves, the aggregative and the breaking, are adopted to improve the effectiveness of the tabu search. Two real cases and some random instances are used for test and comparison. The results show that the stock arrangement was optimized satisfyingly by the tabu search and the rule-based piece arrangement is capable of keeping the working efficiency as usual. In addition, the effectiveness of the tabu search was apparently improved by two proposed replacement moves.