While the movement of fluid through rigid systems is a well-characterized classical problem, predicting the behavior of fluid flow in compliant systems, in which structural 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 geometry and mechanical properties, but also by system energy dissipation and internal and/or surrounding fluid interaction with compliant boundaries. These coupled effects produce nonlinear behavior that becomes difficult to predict, especially for real-life applications, where many parameters vary simultaneously. In this context, a mechanistic understanding of these systems is essential.

In this talk, we will look into our work developing systematic experimental and reduced-order physics modeling frameworks to understand, predict, and guide the design of compliant systems in which interactions between fluids and compliant materials play a central role. First, we will turn our attention to granular jamming actuators, where externally applied pressure changes granular confinement and, in turn, tunes stiffness, yielding, 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. We will then discuss ongoing efforts to extend this programmable mechanical response to architected granular jammed lattices, where unit-cell geometry and pressure-dependent elastoplasticity are combined to tune nonlinear stress-strain response, plasticity, and energy absorption. Finally, we will shift to valveless impedance pumping, a fluid-structure interaction problem in which periodic deformation of a compliant tube generates net flow through wave propagation, reflection, and asymmetry. Through experiments and reduced-order modeling, we examine how actuation, geometry, fluid properties, and material compliance affect the resulting nonlinear flow dynamics. These results provide insights relevant to flow-assist systems, including 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 enable prediction of the effect of numerous system parameters on system performance. 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.