변형률 경계법을 이용한 다중 선상가열에 의한 판의 변형 예측

초록

The purpose of this study is to quickly and accurately predict the deformed shape of the curved plate located before and after the surface of the hull manufactured by multi line heating (or flame bending). Three dimensional thermo-elasto-plastic analysis takes long time and requires user’s guidance to simulate the deformation. To overcome these drawbacks, this study employed the SDB(Strain as Direct Boundary) method based on thermal strain rather than the three dimensional finite element analysis using solid element. The thermal strain, including material phase transformation and volumetric expansion occurred during Martensite phase transformation, is specially considered by SDB. This study calculates the temperature dependent phase portion using material chemical composition and reflects the martensite portion dependent volumetric expansion. The Heat Affected Zone(HAZ) is obtained by thermal analysis and virtual temperature substituting the heat input is assumed by the size and shape of HAZ. In order to reflect the initial deformation due to the former heating lines to the post-deformation analysis, this study predicts the deformation by multi-line heating using the plastic material properties. Thereafter, comparing the deformation of the plate with the 3D solid elasto-plastic analysis and the SDB method, this study shows the accuracy and efficiency of the SDB method.

키워드