誘導加熱曲げのFEM解析: Discussions on the Effects of the Temperature Distribution

The authors study on the technology of an induction bending process and attempt to develop the accurate finite element model for its numerical simulation in which the electromagnetic field-heat transfer-large displacement coupled analysis is required. In the present paper, as part of the research works, a large displacement analysis to bend the STPG370 steel pipe whose diameter is 8 inches, gage is Sch40 by 2DR has been carried out alone and the effects of the temperature distribution given as one of the conditions to the simulation result are discussed. Here, the temperature dependency and the strain rate dependency of the material are taken into consideration. The FE results suggest that wrinkling, a kind of plastic buckling, occurs on the compression side during the whole bending process when the length of the high temperature region over 700°C is too long, for an example, its length which is presently designed around21mm may be shorter than at least 29mm and must not be larger than at least 50mm in this simulation. The mechanical properties of the employed material depend on temperature and greatly change around 700°C. The finding is applicable to the design and management of operational sites and provides guidelines for the required accuracy of the heat transfer analysis which should be coupled with the large-displacement analysis.