STUDY ON THE PREDICTION OF TEMPERATURE OF SHIP PLATES AND HEAT FLUX DUE TO LASER LINE HEATING USING INVERSE AND GREY METHODS ANALYSIS

Article type: Research Article

Authors: Kuo, H.C. | Wu, L.J.

Affiliations: Department of Naval Architecture and Marine Engineering, National Cheng-Kung University, Tainan, Taiwan

Abstract: The line heating process has long been used for plate forming in the building of ships, and has always depended on skilled workers. Since shipbuilding companies need reduction of production costs and an increased use of automation, the line heating process must be improved by performing studies on the temperature of plates. In this paper, which discusses laser line heating of the plates, several methods are proposed to predict the heat flux of the laser source and the temperature fields of the plates. The inverse method and four different Grey methods are used to compute and compare the heat flux of the laser source with prediction of the error in temperature values of the plate in the line heating process. The linear least-squares method is applied to the laser source by boundary conditions in the inverse method. There are boundary conditions for 16 points obtained by experiment. The results of the inverse method for the laser source are found to be in good agreement with experimental results. For the prediction of the plate temperature at the 16 points, four kinds of Grey methods are used to predict the subsequent data for any of the16 points and to estimate the error for different dimensions. The best of the four methods is the New-Dimension-Zero-First-Term G(1,1) Grey method, resulting in errors under 2%. The other 3 methods are the Same-Dimension G(1,1) Grey method, the Same-Dimension-Zero-First-Term G(1,1) Grey method and the New-Dimension G(1,1) Grey method. Keywords: line heating process, Grey method, inverse method

Journal: International Shipbuilding Progress, vol. 48, no. 3, pp. 227-245, 2001