Riveted joint modeling for numerical analysis of airframe crashworthiness

Numerous rivets have to be taken into account to simulate the behavior of aeronautical frames under crash loading conditions. Until now this type of bonding modeling has not been judged satisfactory. The influence of structural embrittlement due to the riveting process, the strength of a riveted joint under dynamic loading and the characterization of a simplified rivet element, in particular, were sources of questions. For each topic, we did solid finite element modeling and carried out experiments to measure the influence of strain rates under quasi-static and dynamic loading conditions. We also determined the elastic–plastic and damage mechanical properties for sheet metal plates and rivet materials. Our results showed that it was essential to develop a new kind of rivet element taking material non-linearities into account. Experiments and solid finite element modeling of an adapted Arcan test procedure were then conducted and pure shear and tensile non-linear responses as well as parameters of a macroscopic criterion were identified. The use of this new rivet element was found to improve prediction of the dynamic behavior for a frame assembled with 700 rivets.