الفهرس 
IntroductionOnly 14 pages are availabe for public view
 |  | from | 16 |  |  |
| | | from | 16 | | |
Abstract
The line heating method is widely used in shipyards to form curved plates of ship structures.
Using this technique, the plate is bent under the influence of the plastic deformation during the heating and cooling cycle. Since the heating process produces inplane shrinkage in the direction normal to the heating line and bending angle around the heating line, a proper selection of the dominant type of these deformations should be taken into consideration to determine the type of heating lines.! Forming of plates using this method is mainly carried out by skilled and experienced workers. Many years of experience are usually needed for craftsmen to acquire the skill required to perform correct jobs using the line heating method. To put this process into practical application in shipyards, the skill and experience of workers for forming curved plates should be replaced by certain mathematical models. Information about the number of heating lines, their types and positions, and proper heating conditions to produce the required shape should be known in advance.
i’ This research is intended to establish computer aided instructions for plate forming by the line . heating method. For this purpose, a number of experiments is carried out to determine the relation between the heating conditions and the resulting bending angle and inplane shrinkage. Then, the necessary number of heating lines, bending heating lines and inplane heating lines, to form unidirectional curved plates and double curved plates should be determined, Based on the idealization of the deflection shape of a bent plate by a single heating line, an algorithm is proposed to estimate the number of bending heating lines to bend a flat plate to an open
. cylindrical surface with variable curvature in the one direction and simultaneously a method is proposed to determine the number of inplane heating lines that produce curvature in the ndicular direction. The proposed algorithm is used to estimate the number of bending ~ting lines necessary to bend the flat plate into an open cylindrical surface with variable
curvature. Afterwards. the proposed method is used to estimate the number of in plane heating lines required to form the curved surface in the other direction with the aid of finite element method. In addition, several experiments are carried out to examine the validity of obtained results and a study case of saddle shape has been invistigated.