Departmental Bulletin Paper An Accelerated Explicit Method with a Two-Stage Computation Scheme for Transient Thermal Stress and Welding Deformation

Ma, Ninshu

44 ( 1 )  , pp.31 - 40 , 2015-06 , 大阪大学接合科学研究所 , Joining and Welding Research Institute, Osaka University , オオサカ ダイガク セツゴウ カガク ケンキュウジョ
An accelerated explicit method with two-stage computation scheme is developed for simulating transient thermasl stress and deformation occurring in a long time welding heating and cooling process. The first computation stage is based on a dynamic explicit method considering the characteristics of the welding mechanical process by controlling both the temperature increment and time scaling parameter. In the second computation stage, a static equilibrium computation scheme is implemented after dynamic thermal loading to obtain a static solution of transient thermal stress and welding deformation. In the two-stage computation scheme, a damping parameter was determined based on a transient radial eigenvalue, which corresponds to a transient welding deformation and is automatically computed using the mass center velocity of the finite element model. The validity of the accelerated explicit method is verified by comparing the transient thermal deformation and residual stresses with those computed by the implicit FEM and experimental measurements.

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