Damage Detection in Grid Structures Using Limited Modal Test Data

Table 5

Grid structure frequencies (Hz).

Mode	Finite element analysis (Hz)	Test result (Hz)	Differences in frequencies (%)	Characteristics
1	90.1	89.84	0.289	Horizontal torsion
2	117.5	117.19	0.264	Overall upward-sloping
3	246.09	248.29	−0.894	Antisymmetric reverse
4	307.7	304.69	0.978	Antisymmetric reverse
5	377.5	380.86	−0.890	Antisymmetric reverse