Figure 4.

Examples of perforated systems which mimic rotating rigid units: (a) systems with diamond-shaped perforations where system in (a-i) has minimal overlap compared to system in (a-ii); (b) systems with star-shaped perforations where system in (b-i) has minimal overlap compared to system in (b-ii); (c) systems with triangle-shaped perforations, where system in (c-i) has minimal overlap compared to system in (c-ii); (d) systems with slits (regular (d-i) and randomly oriented (d-ii)); (e) system with (e-i) regularly and (e-ii) irregularly placed peanut-shaped perforations; and (f) implementation of a rotating squares model as proposed by Mrozek and Strek et al. (2022) [173]. Systems in (a,d,e,f) mimic the rotating squares model, whilst (b,c) mimic the rotating triangles model. Note that, if applicable, systems are being loaded vertically.