الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
 |  | from | 140 |  |  |
| | | from | 140 | | |
Abstract
In shipyards, plates and sections are transferred from storage to the cleaning¬straightening, coating, cutting, forming and welding in subassembly and assembly workshops. Ditfcrent problcms, at1ecting the subscquent labrication process or workers environment, can be induced /Tom applying the necessary fabrication processes in shipbuilding. This thesis is intended to study the various problems induced form used fabrication process that are commonly employed is shipbuilding.
At first, the general information about fabrication processes applied in steel shipbuilding yards is discussed. The common cutting, forming and welding processes applied in steel shipbuilding yards such as mechanical and thermal processes are described.
Afterwards, the problems associated with the thermal fabrication processes are investigated. The source of residual stresses and distortion created from the different thermal processes is explained at first. Consequently, the residual stresses created due to applying cutting and welding are discussed. In addition, the possible types of welding and cutting distortions are described.
Different information about control of cutting and welding distortion is discussed.
At first control of cutting distortion is presented. Then the control of welding distortion through design stages is presented. For examples distortion control before welding, and during welding are discussed. Understanding the effects of variables such as joint location, weld size, sequence of assembly and welding are necessary in determining the causes and cures for distortion. In addition, distortion correction after welding is discussed. The flan1e straightening method as a common distortion corrective process used in shipyards is described.
With respect to worker environment, the types of emissions that are generated from welding and thermal cutting operations are presented. The health effects of these emissions on workers and the problems of environmental impact are explained. Finally control strategies and fume control methods to prevent health-hazard are givcn.
In addition, the problems associated with cold forming process are investigated.
Stress distribution due to plate cold bending is explained. Afterwards, effect of post-