Accurate prediction of macroscopic temperature field in direct laser deposition of large-scale parts using simplified heat source

The characteristics of the temperature field in direct laser deposition (DLD) determine the kinetics and completeness of the structural-phase transformations and have a decisive influence on the residual stress field. The temperature field in DLD depends on numerous factors, such as process parameters (laser power, travel speed, etc.), layer deposition strategy, and the shape of the fabricated part. Experimentally assessing the influence of these parameters on the temperature field is a very labor-intensive task, associated with significant time and financial costs. Therefore, it is most reasonable to use numerical simulation to address this issue. Using standard straightforward simulation approaches for numerical simulation of DLD, implemented in general-purpose finite element analysis software, cannot provide a solution within a reasonable time. In this work, a simplified uniformly distributed heat source coupled with the selective mesh coarsening technique is used for numerical simulation of the macroscopic temperature field in DLD of a large-scale part. The aim of the work is to determine the optimal parameters of the heat source that ensure the required accuracy in predicting the temperature field with minimal computation time. This work includes a numerical and experimental investigation of the temperature field in DLD of a thin-walled cylindrical shell made of 316L alloy. Based on the results obtained, recommendations are proposed for selecting heat source parameters for accurate and computationally efficient simulation of the DLD process.