The Study Of Precise Control In Semi-submersible Platform Building

The21st century is the century of ocean, during which the exploitation of offshore oilwill be developed at a high speed. In this situation, there will be an increasing need foroffshore platform, as well as an opportunity to develop it. In order to develop our offshoreplatform manufacturing rapidly and stably, and to occupy a certain market share, a highperformance precision control system is in urgent need.The main task of the project is to research theories and applications of manufacturingprecision control of semi-submersible offshore platform, based on the precision controltechnology in shipbuilding. Considering the large subsection of offshore platform, to predictwelding deformation, the project applies Inherent strain equivalent load method, and realizesautomatic load and computation and analysis of load through a programming for loadingnodes. Detailed work of the project is as following:Firstly, taking survey in the shipyard to learn actual productive proceed. In order to lay afoundation for the future research, the flow of whole platform manufacturing precisioncontrol and the shipyard workers’ experience about predicting welding s deformation waslearned by survey.Secondly, to simulate some welding forms’ three dimensional transient heat transferanalysis by heat source program, the welding forms include flat surfacing welding and anglewelding. The rule of temperature’s variation through time in the process of welding wasanalyzed. The distribution of structure restraint was obtained by the unit loads method.Thirdly, the welding deformation of structure blocks was calculated by the nodes loadingprogram. It was according to the highest temperature in the process of welding and thedistributions of inherent strain calculated by restrain degrees. The welding deformation canoffer reference for the forecast of compensation amount.Fourthly, the results of calculation was compared and analyzed to the data offered byshipyard. At the same time, the reason of error was also analyzed and the method ofdecreasing welding deformation was proposed.