A Contribution to the Identity Assessment of Ship Structure Plate Parts

Abstract

For the modeling of the ship structure, computer-aided design systems are generally used. During the different phases of the ship structure modeling and production process, the correctness of the generated product model data has to be continuously preserved. The correct assignment of position numbers to steel parts, e.g., represents a fundamental requirement of the ship structure production management. According to this requirement, a quality criterion can be formulated, that all parts to be manufactured have to have a position number assigned to with the condition that only identical parts should have the same position number. Two parts are generally regarded to be identical when they have the same properties concerning material, thickness, and shape. Shape in this case includes the outer and the inner contours (holes). The current control mechanisms of the correctness of product model data are manual, drawings-based methods. A new approach has been developed to automatically check the identity of the ship structural parts already during the design phase. This mechanism allows the engineers to maintain the quality of the product model data before it will be handed on for further processing. The approach described in this article is based on the Fre´chet distance algorithm, which is generally used to assess how closely two continuously closed curves resemble each other. The results of the steel structural parts shape comparison are presented in a report. This report can be used to check the correctness of the position number assignments and by this contributes to the overall quality assurance mechanism to preserve a high quality of the product model data. Although errors can be avoided, which will otherwise be detected in later process phases, they have to be fixed with significant additional costs.