New embrittled shell element for airframe crash simulation

摘要

The paper deals with problem linked to finite element analysis of airframe crash study. Today the limit of Finite Element analysis imposes a minimum shell element size which does not represent local failure due to riveted joints. These local failures are generally critical and it leads the global ruin mode of airframe during crash. It is difficult to find a compromise between computation time (relative to size of model, size of elements, numerical power of tools) and prediction of simulation linked to thin description of geometry which influence generally initiation of crack propagation. In this context a new embrittled shell element is developed. The main topic of this work is to set up a methodology to extract parameters for the characterisation of this new equivalent element. The feasibility of the concept is shown through an example of a punched plate in aluminium alloy. Then, it is proposed under hypothesis to extend this concept to a plate with six holes. The obtained results show interest of the method and ability to improve the representation of a model conserving reasonable computation time.