Composite materials are increasingly used in aeronautical primary structures. This relatively new type of material offers great specific strength but its behaviour is very complex to understand and therefore to predict.
To certify a new type of aircraft, tens of thousands of experimental tests are being performed. Most of them are carried out at the coupon and technological detail scales. These tests are highly conservative, under uniaxial loading, and do not represent the actual behavior at structure scale.
To overcome these drawbacks, a new methodology has been developed at the Institut Clément Ader (Toulouse, France). It relies on a complex loading test rig for technological specimens and a finite element code to simulate laminated composite failures (the Discrete Ply Model). The VIRTUOSE project aims at validating a new methodology to determine the safety domain of a technological specimen (a stiffened panel for example). Only one “envelope curve” test (green ligne on fig 1.) will be necessary thanks to the simulations used to assess the behavior of the structure for different loadings.
Figure 1 : VIRTUOSE methodology to certify composite structures
Recent studies have been carried out on both the influence of the notch and the one of an impact on a laminated composite plate behavior. VIRTUOSE’s next step is to get closer to the real structures by adding stiffeners to the plates and pressure to the loadings.
The VIRTUOSE is being funded by the swiss foundation "Jean-Jacques et Félicia Lopez-Loreta" for a total amount of 1M€.