Non Destructive Evaluation (NDE) is a fundamental step in several phases of the lifespan of structures, that aims at assessing their health status and ensuring their quality.

NDE of aircraft structures, in particular, is a crucial process to ensure passenger safety, industry cost savings and technological advancement. Current visual inspection and lifespan estimation of aircraft are not able to properly assess the health status of structures, especially when damages are present at the interior level and can compromise the integrity of the overall assembly. Composite aircraft, in particular, are subjected to a wide variety of damage that are very difficult to avoid and visually detect.

The need for a NDE tool that can help establish the requirement for further inspection following a GSE impact or similar event motivated this research and the development of inspection prototypes. The technique must be able to easily and rapidly inspect the structure, accessing it only from the outside, and detect defects at different levels of the assembly in a statistically reliable manner.

Exploiting the physics of propagation of elastic and thermal waves and their interaction with material properties and discontinuities, combined to advanced signal processing, damage detection can be achieved and structural integrity assessment can be performed.

In this work, elastic and thermal wave propagation are discussed and investigated in an NDE perspective. Both physics are approached from a first theoretical point of view, their propagation is further observed through simulation analyses and their application is finally implemented in the inspection of representative aerospace composite panels.