Guided Wave Propagation in a Realistic CFRP Fuselage Panel: Proof of Concept for Early-Stage Damage Detection

This paper presents an experimental study of wave motions and a global diagnostics method in a realistic aerospace-grade composite component with a complex design. Due to the frequency dependence of the velocity, wave propagation in anisotropic materials is difficult to describe quantitatively. The analysis of experimental ultrasonic wave propagation and the interactions with discontinuities in thin-walled aircraft structures can provide a plethora of information on the wave structure, the mode shapes, and stiffness reduction. An experiment is devised with a network of various omnidirectional sensor configurations to activate and measure structural responses. The measurement process can be leveraged for flaw detection in large multilayered structures. Physically, this corresponds to analyzing the dispersive behavior and scattering properties of ultrasonic waves, the shape of the waveforms, and their corresponding velocities. Ultrasonic waves are measured in a realistic CFRP fuselage panel in a pristine state and after impacts at different energy levels. Simulations do not allow the wave motion in complex and large design structures to be entirely comprehended. The sensitivity of the guided waves as a damage detection tool is proved for the fuselage structure by an extensive measurement campaign and a probabilistic imaging approach based on health indicator fusion.