Numerical investigation of a novel pattern for reducing residual stress in metal additive manufacturing

Abstract

Deposition patterns can significantly affect residual stress distribution in additive manufacturing processes. In this paper, a novel pattern, the S-pattern, is proposed for the metal additive manufacturing process. The finite element method is used to study the temperature field and the stress field of a cuboid structure under the S-pattern and five other representative patterns: zig-zag, raster, alternate-line, in-out spiral, and out-in spiral. The results show that the S-pattern achieves the lowest values of both equivalent residual stress and maximum principal residual stress, and the warpage of the S-pattern is close to that of counterparts. By analyzing the temperature and stress fields under all patterns, it is found that the residual stress distribution is determined by the uniformity of temperature distribution which is correlated with the peak temperatures of corners. The equivalent residual stress and the maximum principal residual stress are inversely correlated with the average peak temperature and the minimum peak temperature of corners, respectively. These correlations between temperature and residual stress provide an effective approach to evaluate the residual stress of different patterns and guide the deposition process in practice.