Estimating effective elastic properties of 3-D printed specimens using resonant ultrasound spectroscopy

This work continues the investigation of resonant ultrasound spectroscopy (RUS) as a method to characterize the elastic properties of 3-D printed lattice structures. Here, we are focused on lattices fabricated using stereolithography (SLA) with a polyurethane-like resin (Amber) and featuring beam-based unit cells. The RUS analysis leverages the assumption that the diagnostic ultrasound wavelength exceeds the characteristic dimensions of the unit cell. This allows us to treat the 3-D printed structure as a transversely isotropic continuum with effective material properties reflecting the underlying unit cell symmetry. The RUS technique retrieves the five elastic constants for these structures, which are subsequently employed to calculate the elastic moduli. We further compare the elastic coefficients obtained via RUS from both numerical simulations (finite element analysis) and experimental measurements of the eigenmodes. Initial results demonstrate good agreement between experiments and models, highlighting the potential of RUS as a valuable tool for characterizing the elastic behavior of resin-based lattices.