A novel numerical simulation model for a new EB-DED additive manufacturing method: influence mechanism of the interaction between fixture and workpiece

Abstract

The pre-melted electron beam fabrication (PEBF) method is proposed in this paper. Numerical simulation techniques are utilized to calculate the dynamic variations in internal stress and deformation within the component during the PEBF process and its interaction with the fixture. A contact theory is incorporated. Unlike traditional rigid or purely elastic mechanical boundary conditions, our model considers the contact between the workpiece and the fixture, employing Coulomb’s friction law to address the contact issues. The penalty function method is utilized to solve the Coulomb friction problem. The deformation of the deposited material shows minimal reduction throughout the deposition process; each deposition layer contributes to an increase in the deformation at the end of the first layer, although the increment of deformation gradually decreases. During the deposition, the interaction between the fixture and the substrate affects the deformation of the deposited material, with the lateral expansion of the substrate resulting in a reduction in the vertical deformation of the deposited structure. Temperature field analysis indicates that, except for the first layer, the cooling rate variation for subsequent layers does not exceed 15%, suggesting that multiple thermal cycles during additive manufacturing have a minimal impact on the stress and deformation of the existing deposited material.