Soft Material Actuation

Project title: Advanced Integrated Design Optimization Method to Realize Ultrasonic-Phase-Change Actuated Soft Materials

Source of support: National Science Foundation

Actuation, or the transduction of one form of energy to do mechanical work, is the cornerstone for which mechanical systems can be controlled to perform tasks that humans are unable to, unwilling to, and/or inefficient at doing. Recent developments in soft robotics offer unique capabilities where these systems begin to mimic biological motions and materials to perform ever-more-complex functionalities. However, soft robotics that manipulate fluidic pressures inside structures are typically large, since they require pumps, and their flexibility can be limited due to the number of internal tethering needed to route fluid to individual chambers. To overcome this limitation, this project aims to establish a systematic design principle for realizing a completely soft material that can be controlled and actuated using a single transducer mounted at one end. In short, through multi-scale topology optimization, liquid-filled cavities will be pre-patterned within the soft material, where they can be selectively actuated by propagating specific frequencies of ultrasonic waves to induce local shape change and different global states of motion. Thus, like biological systems, shape change will be encoded, during design and fabrication, within the material architecture, which is controlled by a single transducer (like the central nervous system). Fig. 1 illustrates an animation of a prototype ultrasonic-actuated bending structure. The outcomes of this study will push the frontiers of a model-enabled design method for multifunctional materials. The computational model and optimization method will be applicable to a broad range of material designs, thereby paving the way for integrated computational design of smart materials. This research will lead to novel technologies such as micro-ROVs, control surfaces, and micro-propulsion devices, among others.  

Collaborators:

• Prof. H. Alicia Kim, UC San Diego

Peer-Reviewed Publications:

1. H-J. Lee and K. J. Loh, 2019, “Soft Material Actuation by Atomization,” Smart Materials and Structures (0964-1726), IOP, 28(2), 025030. DOI: 10.1088/1361-665X/aaf5a1