I am currently working on the natural frequencies and mode shapes of an insect wing. A real insect wing is made of tough membrane and embedded veins. The latter serves as the stiffening members of a wing. Therefore, LBL films, a polymer of polyurethane with polyacrylic acid, were used to mimic the membrane; while glass fibers function as veins. I made several models by sandwiching the glass fibers into two layer-by-layer films using hot press technique.

A vibration test was performed on this insect wing model. The experimental setup is shown in figure 1 below. One edge of the model was fully glued on a steel plate excited by an electromagnet from 20 Hz to 500 Hz. A high frequency camera was used to record its natural modes.

A computer simulation was built by Abaqus to help determine the natural modes and frequencies. The test and computer simulation presents similar results for natural modes and frequencies. Since the material is stiffer in longitude direction, the oscillation is more significant in transverse direction at high mode shape.