x orthogonality checks are shown in Figure 7 and 8, both MoGeSeC and EI produce good results, although also some low frequency modes present small coupling with maximum levels of about 30%. EI is evaluated better, but it is expected, due to the main selection idea of the method; anyway MoGeSeC maintains quite good result. x MAC matrix between FE and identified modes obtained using respectively MoGeSeC or EI approach is the most significance comparison (Figure 9 and 10). The diagonal results are numerically listed in Table 2, where is shown also the mean value of MAC of the first 7 modes. Although EI results are good (mean value 81.8 %), MoGeSeC performance are excellent with a global increase of almost 5% (mean value 86.7 %). -50 0 50 -50 0 50 -200 -150 -100 -50 0 50 100 150 200 10 9 3 10 12 8 4 8 y axis 2 5 7 7 11 5 1 11 6 2 12 1 6 3 9 4 x axis z axis Figure 5 – Sensor location for the crankshaft. 20 40 60 10 0 10 2 10 4 10 6 10 8 10 10 10 12 10 14 M matrix dofs Omax / Omin 20 40 60 100 102 104 106 108 1010 1012 1014 K matrix dofs Omax / Omin Monte Carlo MoGeSeC EI Genetic Figure 6 – Mass and stiffness matrices conditioning 288
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