While the movement of fluid through rigid conduits is a well-characterized classical problem, predicting the behavior of fluid flow through a compliant tube, in which tube deformation and the behavior of the fluid are strongly coupled, remains a challenge. There are many applications related to soft actuators, adaptive structures, and biomedical transport devices in which understanding this coupling is essential for improving device performance. In such systems, performance is not just dictated by the system’s mechanical properties, but also by compliant boundary deformation, system energy dissipation, and internal and/or surrounding fluid interaction. These coupled effects produce nonlinear behavior that becomes difficult to predict, especially for real-life applications, where many parameters vary simultaneously. Because of this, intuition and trial-and-error are often insufficient for design, and a mechanistic understanding of these systems becomes useful.

In this talk, I will discuss my work developing systematic experimental and reduced-order modeling frameworks to understand, predict, and guide the design of compliant systems where fluid-structure interaction plays a central role. First, we turn our attention to granular jamming actuators, where externally applied pressure changes granular confinement, which in turn tunes stiffness, yield, and energy dissipation. We combine force-displacement experiments with an elastic-plastic beam bending model, linking pressure, geometry, and mechanical response to inform the design of jammed beams with targeted load bearing and recovery requirements. Then, I will discuss ongoing efforts to extend this programmable mechanical response to jammed architected lattices, where unit cell geometry and pressure confinement dependent elastoplasticity are combined to tune nonlinear stress-strain response, plasticity, and energy absorption. Lastly, we will shift to valveless Liebau pumping, a fluid-structure interaction problem where periodic deformation of a compliant tube generates net flow through wave propagation, reflection, and asymmetry. Again, with experiments and reduced-order modeling, we shed light on how actuation, geometry, fluid properties, and material compliance affect the nonlinear flow dynamics. These results provide insights relevant for low-pressure flow-assist systems, such as for the Fontan circulation.

All in all, the goal of this work is to move from the observation of complex experimental behavior to tractable physics-based models that glean insights into why we see what we see. By combining structured experiments with reduced-order modeling, we aim to preserve the essential physics that helps to provide broad design insights while being simple enough for rapid design exploration.