The design of critical, dynamically-loaded structures, e.g. the
fuselage and wings of an aircraft, is characterised by the trade-off
between performance and weight [1]. Moreover, high failure-tolerance,
especially in consideration of unpredictable events such as
impact or operator-caused overload, poses additional design objectives
[2–5]. Modern fibre reinforced composite materials with their
adjustable gradual damage behaviour and high specific anisotropic
stiffness and strength are particularly suitable for the aforementioned
high-performance applications [6]. As a result, an increasing
application of such materials regarding both number and variety
has been observed in recent years.
An important safety-related aspect of the application of composites
is a reliable and accurate identification of the current material
health condition in order to assess the stage of damage evolution
and to avoid catastrophic failure. Normally, the structural condition
is determined using non-destructive tests, such as optical examination,
ultrasonic investigation or computer tomography analysis.
Such approaches are characterised by the necessity of expensive
and labour-intensive preparations, including the disassembly of
components or the application of surface treatment, which reduces
the operational readiness time of the machine under inspection