Insect Legs May Reinvent Tubing
Biomimetic materials are man-made structures that copy what nature has already perfected. In the case of insects, there is much to be learned from their complex and efficient anatomy. The latest research in designing aircraft looks to bug legs to reveal how tubing can be improved.
Thin-walled tubes, often employed in vehicles for lighter weight, have the disadvantage of buckling suddenly. Professor David Taylor, one of the lead researchers on the project, explains.
“It is difficult to predict the loading conditions which cause buckling, especially for tubes of non-standard cross section. Think of a drinking straw. If you bend it, it will suddenly give.”
But insects deal with tremendous stress when climbing, jumping, and pivoting. The legs of cockroaches, locusts, stick bugs and bees are all excellent models for how thin-walled tubes can optimally function.
Cockroaches, for example, stand on legs with nearly circular cross sections (much like a tiny drinking straw). They nearly break their legs when jumping, demonstrating just how precise nature has been in their design.
Stick insects, conversely, have reinforced legs with five longitudinal ridges that run down the sides. “We discovered that these ridges do not prevent buckling, but they do help the legs stay intact. In particular, they help resist a particular type of buckling called elastic buckling. This shows how material properties and geometry can interact in complex ways,” said Taylor, “which must be taken into account when designing thin-walled tubes,”