Abstract
Residual stress in additive manufacturing (AM) is one of the key challenges in terms of structural integrity and finish quality of printed components. Estimating the residual stress distribution on additively manufactured components is complex and computationally expensive with full scale thermo-mechanical FE analysis. In this study, a point heat source is utilized to explore the thermal field and residual stress distribution during the manufacturing processes. Numerical results show that the residual stress at a single material point can be expressed as a function of its spatial position and the peak nodal temperature it has experienced during thermal cycles. The residual stress distribution can be divided into three segments according to the peak nodal temperature. The peak nodal temperature only depends on the heat flux and the distance to the point heat source center. A semi-analytical approach to predict the peak nodal temperature and residual stresses, once the heat flux is known, is proposed. The proposed approach is further validated by a numerical additive manufacturing model and a very good agreement is obtained. Compared to the thermo-mechanical FE model, the proposed method significantly improves the computational efficiency, showing great potential for residual stress prediction.
