Simulation-based approach to estimate influencing factors on acoustic resonance spectra of additively manufactured mechanical metamaterials

Acoustic Resonance Testing is a nondestructive testing method based on the analysis of eigenfrequencies of structures. While it is a well-established technique for conventionally manufactured parts, more research is needed to use the technique to quantify the properties of complex, filigree structures like additively manufactured parts. Therefore, this work examines simulation-based generation of synthetic data to estimate influencing factors caused by additive manufacturing and, more specifically, on metamaterials. Using numerical eigenfrequency analysis, a systematic study of the vibration modes of a Ti6Al4V metamaterial unit cell with multistable mechanical behavior reveals the interplay between the material properties, geometrical parameters, and manufacturing-induced defects. The simulations enable the identification of specific eigenfrequencies for which the highest influence of manufacturing variations on the vibration modes are to be expected in experiments, for example, with regards to the Young’s modulus, spring width, or deflection-induced change in geometry. Frequency shift plots visualize the predicted effects of different parameters and form the basis for future guided experimental design and analysis for complex structures. The simulation-based approach allows a screening of multiple influencing factors, which is not possible experimentally. The simulation-based generation of synthetic data will contribute to the improvement of the interpretation of acoustic spectra and will extend the acoustic resonance testing for more complex structures.