On some features of a plate hybrid-Trefftz displacement element containing a hole

The paper deals with the modelling of riveted assemblies for full-scale complete aircraft crashworthiness. To perform computations aiming at locating rupture initiation in a structure featuring more than 100,000 rivets, it is necessary to model the assembly areas using “super-elements”. If rivet elements have been developed, perforated plate super-elements are still lacking. Thus, the paper focuses on plate super-finite element formulations featuring defects, in particular holes. An original 8-node plate element containing a hole has been selected to discuss on the possibility to extend its formulation from linear (elasticity) to non-linear problems (impact). However, since little is known about the features of super-elements containing a hole, it is first attempted to clarify the properties of the selected existing super-element. This kind of element is defined according to the introduced nomenclature, and the features of its interpolation functions are highlighted. The location of stress fields computed by this super-element is proved to be in close agreement with results provided by standard FE calculations. This super-element exhibits also computational efficiency. These features encourage one to pursue the extension of this super-element formulation to large high plastic strains and strain rates, aiming at localising rupture initiation when performing crashworthiness computations of structures with many rivets and holes.