Topology Optimization for Interface Defect

Switchable adhesive materials have been developed as soft grippers for lifting flat surfaces (such as microchips, glasses, solar panels, and other products) of significantly larger dimensions with high energy efficiency, and have potential in lowering manufacturing costs. Importantly, the magnitude of the adhesive force (i.e., the maximal pulling force) is tunable via external stimuli. For example, when a voltage is applied, the percolating conductive propylene-based elastomer (cPBE) phase carrying a current becomes softened due to joule heating, which leads to re-distribution of stress concentration on the contact surface and thus, a decreased maximal pulling force. An ideal gripper should possess a large pulling force without the stimuli (to be able to pull up heavy objects) and a small pulling force with the stimuli (to be able to drop light objects). Both forces are influenced by both the material properties and defect patterns on the interface. This project investigates the topological design of the interface defects that governs the propagation of cracks under pulling, thus achieving high maximal pulling force. Please see initial model development here.