Keywords

mode tracking, eigenvalues, gradient-based optimization, flutter, discontinuities, mode switching, aeroelasticity

Abstract

In order to construct mode-specific flutter constraints for use in gradient-based multidisciplinary design optimization frameworks, mode tracking must be used to associate the current iteration's modes with the modes corresponding to each constraint function. Existing mode tracking methods, however, do not provide a method by which to ensure the accuracy of mode associations, making them unsuitable for use in situations where obtaining correct mode associations is critical. To remedy this issue, a new mode tracking method is presented which incorporates backtracking logic in order to maintain an arbitrarily high degree of confidence in mode correlations during gradient-based optimization and/or during aeroelastic analyses. This mode tracking method is then applied to the aeroelastic analysis of a linear two-dimensional aeroelastic system. Using this mode tracking method in the context of a gradient-based optimization framework eliminates the need to use constraint aggregation to construct flutter constraints appropriate for gradient-based optimization, allows mode shapes to be prescribed, and allows easily controllable modes to be excluded from flutter constraint formulations.

Original Publication Citation

McDonnell, T., and Ning, A., “Reliable Mode Tracking for Gradient-Based Optimization with Dynamic Stability Constraints,” AIAA Journal, Oct. 2022. doi: 10.2514/1.J061719