Study on the Propagation of Dimensional Deviation in the Hull Block Building Process

Dimensional accuracy of hull block plays a critical role in guaranteeing the whole ship accuracy and reducing the hull butt-joint cost. The current industry practice of dimensional control in shipbuilding mainly focuses on the prediction of cutting and welding deformation based on engineering experience. Its main limitation is that the propagation and accumulation of deviations in the whole building process are neglected. In this article, cutting errors, assembly deviations, welding shrinkages, turnover distortions, and thermal expansions generated at different stages are analyzed. The propagation and accumulation of deviations and variations in the double-bottom block building process are studied based on the measured data in the whole process. Finally, the correlations of deviations between the adjacent stage are concluded. The conclusions can be used to guide the accuracy control in the hull block building process and reduce dimension trimming.