AJS - Jan Zavodnik

Title: Geometric Soft Modes in Thin Surfaces: From Morphing to Flagellar Mechanics Speaker: Jan Zavodnik (University of Ljubljana) Abstract: Thin surfaces admit large deformations through the activation of distinct geometric soft modes, associated with low energetic cost of changing the metric. These include isometric deformations, wrinkling-induced relaxations in classical shells, and shearing and sliding mechanisms in braided meshes, textiles, and bio-inspired meta-surfaces. Such seemingly disparate mechanisms can be understood and modeled within a unified surface-geometric framework and modeled directly at the level of surface kinematics using spectral collocation combined with robust direct energy minimization. Applications range from bio-inspired morphing structures to biological systems, in particular flagellar axonemes, where internal sliding acts as a geometric soft mode driving large-amplitude motion and cell propulsion. The geometric formulation also reveals the mechanisms behind twist–torsion coupling and the non-planarity of flagellar beating, and provides new tools to measure internal activity driving motor action and beating. These insights suggest novel design principles for soft robotic and morphing systems inspired by biological function.