In Nomex honeycomb sandwich structures, inserts are often used for local load introduction. In the surroundings of the inserts, complicated stress conditions occur, which can often lead to local failure of the structure. Due to design measures, several inserts often have to be positioned next to each other, which can lead to interferences of the stress fields, reducing the load-bearing capacity of the individual inserts. For such cases, only rough reduction factors are specified in the ESA insert design handbook, which can lead to large safety factors. To predict the influence of the positioning of two inserts and to minimize oversizing, pull-out tests as well insert proximity tests are carried out. Respective virtual models are build-up for further numerical investigations.
