1-D elastic immersive wave experimentation in an aluminum beam

Abstract

In immersive wave experimentation, a physical experimentation domain is immersed in a larger numerical simulation such that waves in the physical domain drive the numerical simulation and vice-versa. For elastic media, the interaction takes place through sources and sensors at the free surface, where the wavefield is measured and the immersive boundary condition (IBC) is computed and applied. We present a theoretical and experimental study on the implementation of 1-D IBCs for elastic waves in an aluminum beam. Utilizing a 3-D Scanning Laser Doppler Vibrometer (LDV), we measure longitudinal and shear components of a wavefield along the beam. The recorded wavefield is then separated into incident and reflected components and converted into traction. By applying the incident wavefield traction as a boundary condition using a three-component piezo-actuator, we can effectively mitigate broadband longitudinal and shear wave reflections from the boundary, provided the piezo-actuator is calibrated to behave as an idealized point force source. Furthermore, we dynamically link the physical experiment with a numerical background model, introducing virtual scattering. Our results enable elastic immersive wave experimentation at lower frequencies closer to those encountered in real-world scenarios.