Structures

(i) Healable magneto-elastic networks from self-assembly with tunable network patterns and mechanical properties: Magneto-elastic materials have unique mechanical properties arising from the coupling between the magnetic and elastic components, which can be used in many engineering applications, such as waveguide systems, impact mitigation, and soft robotics. Traditional designs of magneto-elastic materials embed magnets or magnetic particles in a monolithic body. Under extreme conditions, the elastic matrices are prone to permanent damage and loss of functionality. We first propose an alternative framework in which 2D magneto-elastic networks were created through vibration-driven self-assembly from a dilute system of elastic bars with sticky magnetic ends. The magneto-elastic unit configuration is shown to dictate the assembled network topology. These assembled networks are demonstrated to fail gracefully at their magnetic bonds under extreme loading and re-assemble under random excitation. The self-assembly and self-healing properties enable them to be fabricated and repaired on-the-fly. The following figure is the schematic representation of the self-assembling and self-healing cycle of a magneto-elastic material we designed. We also investigate how the emergent elasticity of the assembled network depends on magnet and elastic member characteristics theoretically and analytically. This work combines concepts from magnetic handshake materials and thermalized granular systems with elastic network designs to understand the self-assembly, elasticity, and failure mechanisms of elastic bar elements with sticky magnetic ends. It will broaden the engineering applications of magneto-elastic soft materials in the field of fatigue-free reusable protective materials and actuators. We are now working on a top-down design method to relate the desired network topology and mechanical properties to the unit element design in the self-assembly. Codes developed for this project can be found in our GitHub repository.

Fig. Schematic representation of the self-assembling and self-healing cycle of a magneto-elastic material. (Yang, Keten, Advanced Materials Technologies, 2023)