Damage Identification of a Derrick Steel Structure Based on the HHT Marginal Spectrum Amplitude Curvature Difference

Figure 5

Relationship between the difference of the HHT marginal spectrum curvature and the nodes.

(a) Condition 1 (damage of unit 16; HHT method)

(b) Condition 2 (damage of unit 10; HHT method)

(c) Condition 3 (damage of unit 5; HHT method)

(d) Condition 1 (damage of unit 16; IMF method)

(e) 10% random noise (damage of unit 5)

(f) Condition 4 (damage of units 8 and 14; HHT method)

(g) Condition 5 (damage of units 5 and 13; HHT method)

(h) Condition 6 (damage of units 5 and 13; HHT method)

(i) Condition 6 (damage of units 5 and 13; IMF method)

(j) 10% random noise (damage of units 5 and 13)