Characterizing the Dynamic Response of a Foam-Based Testbed with Material, Geometric, and Experimental Uncertainties

Closed-cell polymer foams are commonly employed as support structures to absorb shock and vibration in mechanical systems. Engineering analysts responsible for system designs that incorporate these foams must understand the effects that intrinsic and extrinsic conditions have on their dynamic responses. Parameters intrinsic at the system level, such as preloading and material properties, along with extrinsic environmental parameters, such as forcing energy and frequency, have the potential to drive the system into nonlinear or chaotic regimes. A suite of simulation-based studies is performed utilizing finite element (FE) analysis to investigate both intrinsic and extrinsic model parameters to understand such effects on the nonlinear system dynamics. A high-fidelity FE model of the mass-foam testbed needs to be developed to perform two tasks – implicitly determine stress states from precompression in the foam and explicitly solve for the system’s response when subject to various dynamic inputs. Using prior knowledge of stochastic quantities in the model, input parameter distributions will be generated to quantify the influences on the system’s dynamic response behavior. An existing testbed consisting of a mass suspended by two pieces of closed-cell polymer foam will be used to perform various experiments for model validation. This project aims to explore the parameter spaces to predict, validate, and confidently bound the nonlinear dynamic behaviors of a system.