8.1 Virtual testing of design alternatives
159
This is confirmed by the visual output of the virtual tests, which are given in Table 30.
From this it is concluded that the Reference exhibits the same damage progression as
the previously investigated partially potted inserts (compare with Figure 114, p. 145).
However, the Hourglass and Undercut alternatives ae equally distinct. Here the final load
drop is not caused by tensile failure of the core under the potting. Instead, buckling of
the lower face sheet causes catastrophic failure (see Table 30). In sum, the virtual test
study suggests that Undercut and Hourglass design yield comparable strengths. Therefore, the large borehole of the Hourglass insert does not appear to negatively affect the
pull-out strength. Considering that the Undercut weights about 12% more than the Hourglass design, the latter is superior in terms of light weight design. In comparison to the
Reference, both designs with increased potting radius suggest a considerable increase in
weight specific strength (up to 100%).
Table 30 Visual damage in the post failure regime of all three design alternatives
Reference
Hourglass
Undercut
Buckling
Tensile core
rupture