## 4 Closing Remarks  
In this work, the effects of AM constraints and three different design objectives (i.e., compliance, stress, and multi-objective) on structural topology optimization were investigated. It was found that the build orientation plays a significant role when considering AM constraints in topology optimization, although its effectiveness varies depending on part geometries. The inclusion of AM constraints increased the optimal value of the objective function in the topology optimization but significantly reduced the required support structure volume. Comparing the results of the three different objective formulations, it was found that the average objective increase was the highest under compliance minimization (i.e., 16.19%), while the stress and compliance minimization had the lowest deviation increase (i.e., 6.89%). The average reduction in support volume was similar for all three cases. The reduction in the support volume demonstrates the potential for  
Figure 19: Comparison of the support structure volume (1, 4, 7: cantilever; 2, 5, 8: bridge shape; 3, 6, 9: L-shaped beam). Figure 20: Average change in design objectives and support structure volume between the optimization with and without AM constraints (1: compliance minimization, 2: stress minimization, 3: compliance and stress minimization). material efficiency and cost savings in AM. In the cantilever and L-shaped beam examples, the topology optimizer converged to more simplified shapes to reduce support structures when AM constraints were added. Depending on specific part geometries, it is likely that the part volume will increase to reduce the support structure volume, so the total volume, including part and support structure volumes, may remain relatively unchanged. Conceptualization, B.D. and S.J. ; methodology, B.D. and S.J. ; software, B.D. ; validation, B.D. ; writing--original draft preparation, B.D. ; writing--review and editing, B.D. and S.J. ; supervision, S.J. ; funding acquisition, S.J. All authors have read and agreed to the published version of the manuscript. This work was supported by the SIUC startup fund. * [PERSON] and [PERSON] (1988) [PERSON]; [PERSON] Generating optimal topologies in structural design using a homogenization method. _Comput. Methods Appl. Mech. Eng._**1988**, _71_, 197-224. [CrossRef]
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