FEM-based Resonant Ultrasound Spectroscopy Method for Measurement of the Elastic Properties of Irregular Solid Specimens

Resonant ultrasound spectroscopy (RUS) is a well-established method of identifying the elastic coefficients of solid materials. The Rayleigh-Ritz method (RRZ) is usually used to calculate the natural frequencies of a specimen, where the specimen needs to be processed into a certain regular body. This requirement is hard to meet for some materials with size limitations or special physical/chemical properties. Our objective was to address this limitation with a new approach adapted to specimens of arbitrary geometry by combining RUS with micro computed tomography (μ-CT) and finite element modeling (FEM). The accuracy of the proposed approach was assessed using titanium irregular specimens. The elastic coefficient results showed good agreements (below 2%) with values of a rectangular parallelepiped specimen measured by the RRZ-based RUS. This study overcomes the limitation of RUS to specimen geometry and allows identification of the elastic properties of irregular specimens with good accuracy.