| Welding is widely applied in ship construction in modern shipyard. However, some deformations will be generated in structures after welding due to the non-uniform thermal effect. At present, welding deformation is usually solved by mechanical straightening and flame straightening. Flame straightening is more widely applied in shipyard, but it has some disadvantages such as influence on material properties and damage on material coating surface. With the improving high frequency electromagnetic induction heating technology, its application on straightening has got much attention of the shipyard and research institutions.The present deformation prevention and straightening methods in shipyards are firstly introduced in this paper with some explanations on the principle of flame straightening and the research status of induction straightening technology at home and abroad. The principle of high frequency electromagnetic induction heating is also explained and compared with flame straightening before the advantages of high frequency electromagnetic induction heating straightening technology are listed.Mechanism of straightening in electromagnetic induction heating is studied by an instance of correction angular distortion of T sections. After establishing the finite model of electromagnetism-thermo-structure coupled system and numerical simulation calculation by ANSYS, correcting mechanism of is analyzed by the instance. Then, the effects between straightening result and plate thickness, air gap and heating time are studied in detail. It is found that when other parameters are same, straightening result is increased by the decreasing of plate thickness and air gap. Besides, the result also increases as heating time becomes longer.A mathematical model of straightening results with influence parameters is established with SPSS software based on the above calculated results. The model is checked systematically to verify its imitative effect. |
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