Bio-Inspired Sensitivity-Weighted NSGA-II Optimization of a 6-UPS Parallel Loading Mechanism for Aero-Engine Pylon...

Area of Science:

• Aerospace Engineering
• Mechanical Engineering
• Computational Mechanics

Background:

• Conventional structural static testing methods for aerospace components face limitations in replicating complex flight loads due to fixed loading axes and parasitic torques.
• Accurate simulation of aero-engine pylon flight loads necessitates omnidirectional vector loading, high stiffness, and efficient force transmission, posing a significant geometric synthesis challenge.
• Evaluating the nonlinear, coupled workspace, stiffness, and load-capacity indices of such mechanisms is computationally intensive.

Purpose of the Study:

• To develop an efficient geometric synthesis methodology for a task-specific 6-degrees-of-freedom (UPS) loading mechanism for aero-engine pylon static testing.
• To introduce a bio-inspired optimization algorithm that addresses the computational bottleneck in mechanism design.
• To improve workspace, stiffness, and load-carrying capacity while reducing design computation time.

Main Methods:

• Development of a task-specific 6-UPS loading mechanism.
• Implementation of a bio-inspired sensitivity-weighted Non-dominated Sorting Genetic Algorithm II (NSGA-II).
• Estimation of design-variable sensitivities using Multivariate Adaptive Regression Splines (MARS) to guide the optimization process.
• Validation through numerical simulations and testing of a hybrid physical prototype.

Main Results:

• The bio-inspired NSGA-II algorithm reduced computation time from approximately 30 hours to 3 hours compared to baseline NSGA-II.
• Simultaneous improvements in workspace, stiffness, and load-carrying capacity were achieved.
• Physical prototype testing demonstrated force magnitude errors below 0.64% (63.42 N) and directional deviations below 1.15° across 240 loaded poses.

Conclusions:

• The proposed bio-inspired optimization-based design methodology is effective for high-fidelity static testing of aero-engine pylons.
• The developed 6-UPS loading mechanism and optimization approach offer significant advantages in efficiency and performance for aerospace structural testing.
• This approach provides a robust solution for complex loading requirements in critical component validation.