Abstract
To clarify how butterflies stabilize the flapping flight, this study discusses an effect of structural flexibility of butterfly abdomen and wings. The effect of flexibility is evaluated on butterfly free flight based on numerical simulation with a panel method. A butterfly is modeled by rigid body with 4 links. In an abdomen flexible model, the whole abdomen flexibility is expressed by a joint with a spring and damper. Also in a wing flexible model, flexibility along feathering axis is expressed by a joint with a spring and damper. The stability of flapping flight is measured by the time of flight within which the butterflies continuously fly without falling down. Compared with a non-flexile model, an abdomen flexible model and a wing flexible model can fly longer, but the characteristics of these flexible models are different.
