PSI - Issue 24

Giulia Morettini et al. / Procedia Structural Integrity 24 (2019) 349–359 Author name / Structural Integrity Procedia 00 (2019) 000 – 000

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possible to obtain the stress state map, both for the specimen still on the platform and after cut-off. To obtein accurate residual sress results from the software simulator, a validation based on the specific parametric set, and the used material is necessary Xing (2018) and Shubhra (2016). For this reason in Figure 5 and Figure 7, only a qualitative evaluation, in term of vertical displacemt and stress after cut-off has been reported with which it is possible to do a relative comparison between the two case studies (Horizontal and Vertical).

Fig. 5. Qualitative analysis of vertical displacement after cut-off, comparison between Vertical and Horizontal built specimens.

The vertical displacement (in the build direction) suffered by the elements, with which the FE analysis discretizes the specimen, is certainly predominant respect to that in the other directions, Meneghetti (2019). According to Figure. 5, when looking at the displacement in a particular single layer, the points at the longitudinal ends of the section generates displacements in the z direction, due to the process of shrinkage because of solidification. If this process is not properly kept under control (through the use of an adequate parametric setting and adequate support elements), there is the risk of getting off the platform, with consequent interruption of the molding process, Shunyu (2019). From Figure 5 it is possible to highlight how, in the horizontal specimen, there is a marked opposition between the peripheral areas (in red) which represent positive displacements, and the central area (in dark blue) in which instead it is possible to arrive at negative displacement. This situation, although of a more modest size, occurs in the same way in the vertical specimen.