Approach for analysis and design of composite rotor blades

Abstract

The developments in tilt rotor technology allow rotor blades to have different twist and rpm requirements in hover and in forward flight to optimize for operational conditions. The available twist of the rotor blade for different flight regimes bears on the performance of the flight. This article presents a detailed analysis of a typical rotor blade, the focus being the static response in the presence of extension-twist coupling induced due to asymmetric stacking sequence of laminas. The baseline rotor blade is modeled as a D-shaped spar using discrete Kirchoff theory-based finite elements. A method is proposed to derive six configurations of blade starting from a base rotor blade made of three laminated shells. The effects of varying rpm and lay-ups for the six configurations are presented as carpet plots in terms of the available tip twist angle. Such plots may be used in the rotor blade design trade-off studies.