دانلود Determination of Residual Stresses Numerically Obtained in ASTM AH36 Steel Welded by TIG Process

Abstract

Residual stresses have been numerically determined in welded joints. In this study, the numerical model is based on the coupling  of  different  physical  phenomena  considering  the  thermal,  mechanical  and  metallurgical  nature  of  a  welding process.  The ABAQUS software program  was  used  to perform  the numerical  simulations,  based on the finite  element method (FEM). The aspects related to the mathematical modeling of complex welding procedures were pondered with the  FEM:  variations  in  the  physical  and  mechanical  properties  of  the  materials  as  a  function  of  the  temperature;  the transience  and  the  speed of  the welding  process,  the  material  phase  transformations;  the different  mechanisms  of heat  exchange  with  the  environment  (convection  and  radiation);  all  them  associated  with  a  high  level  of  nonlinearity.  The  heat source used in this analytical model for heat supply was the double ellipsoid model proposed by Goldak, in which a 60 mm × 50 mm and 3 mm rectangular ASTM AH36 steel plate was used for the TIG process simulations. Throughout this work, the optimization of the welding procedures currently practiced in petrochemical and ship building industries can be applied to reduce the levels of residual stresses.