Iterative real/complex eigen-solver and parallel processing for nonlinear panel flutter analysis

In the frequency domain analysis of the limit cycle motion of a fluttering panel, the operation of a nonlinear eigen-solution is computationally costly. Nonlinear panel flutter analysis includes repeatedly using real and complex eigen-solutions in iterations and in the searching of the stable limit cycle motion. This study presents an efficient iterative real and complex nonlinear eigen-solver to greatly speed up the solution procedure. This new nonlinear eigen-solution adopted a power iteration-scheme and has the following features: (1) it avoids repeatedly using a costly eigen-solver, (2) it is not sensitive to the initial iteration vector, (3) it operates in the real region for a complex solution, and (4) it solves for the single nonlinear mode deflection directly. Those features are particularly suitable for nonlinear panel flutter analysis in which the limit cycle motion is a stable vibration, the eigenvalue and eigenvector are amplitude related and only the dominant eigenvector has a practical meaning.

The parallel computation is designed to speed up the searching of the stability of the limit cycle motion. The parallel computation was performed by using PVM (Parallel Virtual Machine) on IBM RS/6000 workstations.