Figure 2

Comparison between FRF measured (in cyan) and FEM simulation (in orange) obtained with the estimated elastic constants. In the example, plate 4 is considered. The resulting magnitudes are normalized between 0 and 1. Measurements from white specimens were fitted as in²³ and using Rayleigh damping with constants \(\alpha =10\) [\({\hbox {s}^{-1}}\)] and \(\beta =2\times 10^{-6}\) [s], according to²⁴. The eigenfrequencies obtained numerically and corresponding to resonances in the measure are highlighted with dashed red lines. In the measurement points chosen, modes with a nodal line along the longitudinal axis of symmetry are attenuated, e.g. (1,1) (colored in gray), making the peaks of interest easier to identify. The mode shape associated to each resonance is depicted above the plot, denoted with a notation based on nodal lines and widely used in the literature²⁵.