## 5 Conclusions and Outlook  
The integration of several functions in one part is a possible approach for saving material and thus weight. However, this often results in complex structures that cannot usually be derived intuitively. This can be remedied by computer-aided tools such as topology optimization which provide a design proposal for the part based on a given load case. In order to manufacture these parts very close to the result of the topology optimization, AM presents a potential solution. This is due to the high design freedom as well as the omitted manufacturing costs for complex tools such as dies. However, AM entails special characteristics regarding the material properties resulting from the manufacturing. In SLM, for example, three porous areas can be created in the layer planes along the print direction depending on the shape of the part and the given process parameters. These porous areas also influence the material properties in the resulting part. As a result, there is a direct interrelation between the manufacturing and the design of the part. This contribution presents an optimization method which considers the three porous areas and the associated material properties during a sensitivity-based topology optimization in Tosca Structure. For this purpose, the topology optimization is interrupted in each iteration after the fictive density distribution has been determined and the smoothed interim result is exported. Subsequently, the three porous areas including the material properties are determined, adopted in the interim result and passed back to the optimization. Thereby, the sensitivities are calculated by Abaqus, and the implemented MMA algorithm implemented in Tosca carries out the adjustment of the fictive densities for the next iteration. As soon as the convergence criterion is reached, a design is available which is generated on the basis of the material properties resulting from the SLM under the given process parameters. From the investigations of the optimization method based on a three-point bending beam, it can be concluded that by iteratively interrupting and adjusting the material properties, a design is generated which, compared to a standard topology optimization, has an increased contour area and tends to favor thin structures. As a result, a slightly higher volume-specific stiffness can be achieved under the given boundary conditions for the three-point bending beam compared to the design of the standard topology optimization. Thus, the optimization method can contribute to the design finding in early phases of product development and offers a basis for further extensions. Such extensions are necessary since the results show that the topology optimization results can lead to structures that do not include all three porous areas everywhere and  
Figure 12: Section in the layer plane through the design from the developed optimization method: front view (**top**) and plan view (**bottom**). thus do not completely represent reality correctly. By using a minimum wall thickness in the optimization method, the possibility should be created to better represent the three porous area and thus the reality more closely in the future. In addition, the division into the areas results in an abrupt stress progression which could lead to an overestimation of the damage limits, especially in a standard topology optimization. In order to prevent such a potential overestimation, a global strength constraint shall be considered in the developed optimization method in the future. In further investigations, which are not focused in this contribution, the comparison between simulation and experiment will be established. For this purpose, the resulting designs from the developed optimization method as well as a standard topology optimization will be manufactured, characterized and investigated on a test bench. Conceptualization, J.H. and S.L. ; methodology, J.H., S.R. and A.A.; software, J.H. and S.L. ; writing--original draft preparation, J.H. and S.L. ; writing--review and editing, J.H. and S.R.