*Engineering Problems - Uncertainties, Constraints and Optimization Techniques*

**Figure 12.** *Second torsion mode (case 1).*

#### **Figure 13.** *First torsion mode (case 2).*

**Figure 14.** *Second bending mode (case 2).*


#### **Table 4.**

*Frequency errors between test and optimization.*

*Verification and Validation of Supersonic Flutter of Rudder Model for Experiment DOI: http://dx.doi.org/10.5772/intechopen.98384*

From **Table 4**, the error of the first frequency is less than 1%, and that of the second one is not more than 1.5%. Again, it represents optimization design is very successful.
