Imperfections by Design: Interactive Buckling and postbuckling in Architected Materials*

Harnessing elastic instabilities in materials has recently enabled new classes of tunable systems and devices, such as gating mechanisms, artificial muscles, and soft robotics, etc. The common feature of those instability-induced smart systems is the amplification of force and motion compared to their traditional stiff counterparts. Achieving these amplifying effects usually relies on harnessing tailorable architected materials as the building block. One of the challenges is how defects change the properties of architected materials to achieve targeted functions with aperiodic materials. In response to such need, we introduce a class of shell structures which undergoes interactive buckling. By combining finite-element simulations and desktop-scale experiments, we found that the interactive buckling can be induced by strategically controlling the number and the distribution of defects, leading to a deterministic actuation response compared to the one without geometric defects. Our study thereby opens avenues for the design of next-generation actuators and robots with high fidelity and low sensitivity over a wide range of length scales.