Presentation of a methodology for delamination detection within laminated structures

A methodology aiming at taking into account delaminated composite structures behaviour has been developed. This study falls into two parts: • The first one tackles the delamination detection within damaged thin laminated structures. In the finite element method (FEM) computational code, those laminated structures have been modelled using multi-layered shell elements. The methodology uses post-process criteria, based on fracture mechanics linked with damage mechanics, of computational code by the effective stress tensor. • In the second place, the influence of delamination over the overall behaviour of the structure is taken into account. This influence is introduced by locally changing material characterization, quite progressively during the loading phase. These integrated effects change the numerical behaviour on loading and energy curves. The validation is carried out with experimental low velocity impact tests on the bending tests. A satisfactory coherence is shown for damage mechanisms and delamination shapes, in different examples. The methodology developed is recognized a predictive process for several laminates under study. It can be used as a potential tool to size laminated structures at design stage. We will present the different aspects of this delamination approach.