Concept for morphing airfoil with zero torsional stiffness

•A twist morphing aerofoil structure is described.•The structure comprises prestressed carbon fibre reinforced plastic members.•Torsional stiffness is tailored by modifying material prestress.•Zero torsional stiffness can be achieved to reduce actuation requirements.

A morphing wing structure is presented which is designed to have zero torsional stiffness to minimise actuation requirements. The concept consists of carbon fibre reinforced plastic strips which are initially curved prior to being flattened and assembled into a grid-like structure in a heightened state of elastic strain energy. Varying the initial curvature of the strips, material properties and the assembled geometry enables the torsional stiffness to be tailored. A state of zero torsional stiffness can be obtained when there is a balance between the changes in strain energy associated with bending and twist deformations.