Mechanics of instability-induced pattern transformations in elastomeric porous cylinders

In this paper, we combine experiments and numerical simulations to investigate the large deformation mechanics of periodically patterned cylindrical structures under uniaxial compression. Focusing on cylinders with a square array of circular pores, we show that their buckling behavior is not only controlled by the porosity (as for the case of the corresponding infinitely large planar structures), but also by the length and thickness of the shell and the number of pores along the full circumference. While infinitely long cylindrical shells only support long wavelength (global) modes, by reducing the length and tuning the thickness, short wavelength (local) modes can be observed. Furthermore, frustrated short wavelength modes are triggered when a local instability is critical, but the buckling pattern is not compatible with the number of pores along the circumference.