Table 2: First-order frequencies of the EPSB under different prestress forces.

Pretension Value
(kN)
Theoretical
Value (Hz)
Change Rate
(%)
Simulated Value
(Hz)
Change Rate
(%)
Relative Error
(%)
0 52.24 52.02 0.42
200 51.70 -1.04 51.72 -0.58 -0.04
400 51.15 -2.08 51.38 -1.22 -0.46
600 50.60 -3.14 51.02 -1.91 -0.84
800 50.04 -4.21 50.64 -2.65 -1.19
1000 49.47 -5.29 50.23 -3.44 -1.51