A design and analysis of a morphing Hyper-Elliptic Cambered Span (HECS) wing

The HECS wing, developed by NASA Langley Research Center, features a nonplanar, hyper- elliptically swept leading and trailing edge as well as spanwise camber. In this paper, we propose a single-degree-of-freedom mechanism to provide a means for the wing to continuously morph from a planar to a nonplanar configuration. The mechanism, which is something like a scissor linkage, uses a repeating quaternary-binary link configuration to translate the motion from one wing segment to the next. The mechanism is synthesized such that, with one input to the first seg- ment in the chain, the other wing segments move into their desired positions. To predict the aerodynamic loads associated with this morphing dihedral change, linear theory is applied to the HECS wing configuration at distinct morphed positions. For the structural study, a finite ele- ment representation of the mechanism is developed, and a linear static analysis at different morphed positions is performed. Using the predicted aerodynamic loads, the structural analysis investigates different materials and cross sections of the mechanism members to determine a need for redesign due to failure from buckling and bending stress. A design is finalized which, com- pared to the design of the original model, lightens the structure as well as increases its strength. These results are beneficial for the next phase of model development of the mechanism. This work shows that a relatively simple kinematic mechanism can produce the desired range of mo- tion for a variable dihedral HECS wing. It also provides insight into the aerodynamic effects of the nonplanar wing configuration with an analysis of the structural integrity of the mechanism under loading.