Aeroelastic Analysis of a Composite Wingbox with Varying Root Flexibility

Abstract

The research looked into the aeroelastic properties and modal response of a composite rectangular wingbox. This research attempted to assess the sensitivity of the flutter speed, divergence speed and modal response when varying the composite skin lay-up, fibre orientation, and the root flexibility of the model. All this research was conducted using the finite element code ASTROS. An attempt was made to cover as extensive a field as possible and identify interesting areas that required further examination. Interesting relations were found between the following properties: EI/GJ versus fibre orientation and various mode ratios versus root stiffness. These could be linked with the changes in flutter and divergence speed of the composite model. In certain regions of the root flexibility, the flutter and divergence speeds showed dips and peaks. These coincided with changes in modal behaviour and were verified with a visualisation tool.