A Study on Weldment Boundary Condition for Elasto-Plastic Thermal Distortion Analysis of Large Welded Structures

Ha, Yunsok

Journal of KWJS 2011;29(4):48-53.
Published online September 12, 2011.

대형 용접구조물의 탄소성 열변형 해석을 위한 용접부의 변형률 경계조건에 관한 연구

A Study on Weldment Boundary Condition for Elasto-Plastic Thermal Distortion Analysis of Large Welded Structures

Abstract

A thermal distortion analysis which takes strains directly as boundary conditions removed barrier of analysis time for the evaluation of welding distortion in a large shell structure like ship block. If the FE analysis time is dramatically reduced, the structure modeling time or the input-value calculating time will become a new issue. On the contrary to this, if the calculation time of analysis input-value is dramatically reduced and its results also are more meaningful, a little longer analysis time could be affirmative. In this study, instead of using inherent strain based on elastic analysis, a thermal strain based on elasto-plastic analysis is used as the boundary condition of weldments in order to evaluate the welding distortion. Here, the thermal strain at the weldment was established by using a stress-strain curve established from the test results. It is possible to automatically recognize the modeling induced-stiffness in the shrinkage direction of welded or heated region. The validity of elasto-plastic thermal distortion analysis was verified through the experiment results with various welding sequence.

Key Words: Thermal distortion analysis, SDB Method, Stress-Strain curve, Elasto-Plastic, FEM