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A modeling tool is proposed to describe the vibration behavior of pristine and damaged plates in the medium frequency range (below 10 kHz). This tool is intended to provide a platform for the development and assessment of damage detection algorithms for aircraft structural health monitoring applications. The proposed analytical model employs a Hierarchical Trigonometric Function Set (HTFS) to characterize homogeneous plates with through cracks. This approach takes advantage of the very high order of stability of the HTFS [O. Beslin and J. Nicolas, J. Sound Vib. 202, 633–655 (1997)] to approximate the effects of a small crack in a plate for all combinations of classical boundary conditions (e.g., CFSC, CCFF, FSFS). The model is first presented and then assessed for healthy and cracked CCCC plates with eigenvalues and eigenmodes presented in the literature. For a healthy square plate, numerical results provide good agreement up to the 1000th mode while, for a cracked rectangular plate, good agreement is obtained up to the 3rd mode, corresponding to the highest mode order available in the literature. Wave propagation simulation obtained from HTFS shows the scattering around the cracks in the plates. Experimental validation of the model is conducted both in frequency and time domains for healthy and cracked plates. [Work supported by the Consortium for Research and Innovation in Aerospace in Quebec (CRIAQ) and Defence R&D Canada.]

Research efforts at Bombardier Aerospace have investigated design constraints that need to be addressed when considering the design of a future unconventional fuselage concept. Using a composite design platform integrated with structural health monitoring (SHM) technologies, the design space is broadened and there are many more unknowns to investigate from our current knowledge of the subject to date. The principal idea is to identify structural zones and quantify stress levels in areas of concern, referred to as ‘hot-spots’, by integrating an SHM system at a conceptual design level. This new concept would require an assessment of benefits and detriments in order to evaluate the certification processes, impact on maintenance, operation, and ownership costs. The integration of an SHM system using onboard sensors introduces many challenges, such as the requirement for multiple sensors in the structure and additional systems weight. The investigation shows how the aircraft structural design would be impacted and how design, stress, supply-chain, manufacturing, and the systems departments need to be harmonised in order to design a feasible and integrated SHM-structural fuselage concept.

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