Because the flutter phenomenon is usually associated with large deformations/deflections, the structural solution based on linear theory gives inaccurate or totally unphysical solution because the equilibrium of the structure is referred to the initial state of the structure. Therefore, the changing geometry of the structure has to be taken into account in order to accurately describe the fluid/structure interactions at the onset of flutter, or in the post-flutter regime. To date, to the best knowledge of the authors, nonlinear analyses, even if developed, have not yet been applied to flutter analysis with Euler/Navier-Stokes equations. Therefore, the objective of the present study is to develop the structural analysis using the second Poila-Kirchhoff stress and Green-Lagrange strain, a pair of energetically conjugated tensors which can accommodate arbitrary large deformations, to study the flutter phenomenon. Since both of these tensors are objective tensors, i.e., the rigid-body motion has no contribution to their components, the movement of the body, including maneuvers and deformation, can be included.