Design and Testing of a Compliant Mechanism-Based Demonstrator for a Droop-Nose Morphing Device

A demonstrator morphing leading edge was designed and manufactured as an intermediary step in preparation for wind tunnel testing of a droop-nose adaptive morphing wingtip (AMWT) as part of the European FP7 project NOVEMOR. This demonstrator features a flexible fiberglass skin and a monolithic aluminum internal compliant mechanism and support structure for lightweight design. The design process involves the design of the skin via a structural optimization tool, followed by continuum gradient-based topology optimization of first the compliant mechanism and then the support structure. The skin was manufactured using prepreg Hexcel HexPly® 913 plies, the aluminum internal structure was laser cut from stock plate material and the compliant region was driven by a linear stepper motor actuator. Displacements and strains were measured and compared with target values and that of finite element computations and overall show good agreement; however issues such as grey-areas and hinge-regions in the topology optimization need to be addressed for the final wind tunnel design for better post-processing and reduced stress concentrations.