Rigidity paradox of kirigami arches

The geometry of bending-active kirigami arches, decorated by cuts and holes, is strongly influenced by the location and geometry of the perforations. This study demonstrates that, in some instances, the geometric strengthening induced by additional cuts can outweigh the weakening effect of material removal, leading to a counterintuitive increase in structural rigidity under a given concentrated load. We present multiple parametric cut patterns to show that rigidity can be increased both under symmetric and asymmetric loads. While the preferred cut location is often near the point of action of the load, asymmetric loading can shift this optimum elsewhere. Moreover, the distance between the supports also plays a crucial role, namely, the rigidity gain vanishes when the supports are too far apart. We found that the rigidity can be increased for both non-perforated and perforated sheets, and there is a non-monotonic relationship between the global porosity and the rigidity of the structure. Numerical predictions are validated against experimental measurements. • Numerical and experimental results show that additional cuts can increase the rigidity of bending-active kirigami arches under concentrated load. • Rigidity can be increased for both non-perforated and perforated sheets. • The effect occurs under both symmetric and asymmetric loading conditions. • Achievable rigidity gain decreases with increasing support distance; for large spans, the effect may disappear. • Optimal cut placement depends on both load symmetry and support distance, and is not trivial to determine.