Nonlinear vibro-thermal-acoustical damage imaging in composites by selective activation of defects using time-reversal elastic waves

Fiber reinforced polymers (or composites) have excellent specific stiffness/strength as well as corrosion resistance, which makes them very attractive for high-tech applications in aerospace, renewable energy … Though, composites are also known for their susceptibility to internal defects which might compromise their structural performance. The goal of this project is to develop a low-cost and time-efficient non-destructive inspection technique by employing elastic waves. The idea is to employ the principle of wave time-reversal coupled to decomposition techniques in order to selectively focus vibrational energy at defects. By doing so, defects will get highly active and become themselves a secondary source of nonlinear vibrations, heat and/or acoustic emission. Tracking down these secondary effects offers a unique opportunity to get an exclusive imaging of defects in materials. The study will involve both experimental and numerical research in order to get a deep understanding of the various involved physical phenomena, and to optimize the technique for the wide diversity of possible defect types in composites.