A Model-Based SHM Strategy for Gears—Development of a Hybrid FEM-Analytical Approach to Investigate the Effects of Surface Fatigue on the Vibrational Spectra of a Back-to-Back Test Rig. - Concli, Franco; Pierri, Ludovico; Sbarufatti, Claudio; Surace, Cecilia (Applied Sciences (2076-3417), 2021)