Abstract:

Rigid thin elastic fibers embedded within a soft matrix are ubiquitous in biology, for instance, microtubules in cytoskeleton within living cells. In the oil industry, the constrained buckling of oil pipes is also a challenging problem. To understand the complex yet poorly understood physics of mechanical instability of such a system, we have built a mimic hard-soft fiber composite model system and studied its mechanical instability using micromechanical experiments and variational theory. We show that the buckling rod follows an exponentially decaying profile and that the transverse and longitudinal coupling between the rod and the surrounding elastic medium determines the profile. A linear model is proposed and shown to predict reasonably the mechanical behavior of such a system in short wavelength buckling regime. As deformation increases, however, a dynamic transition from the throughout short wavelength buckling regime to a localized failure regime is predicted and observed. These findings provide insights into both microtubule mechanics and design principles towards biomimetic devices taking advantage of reinforced thin rod buckling instability.