Resonant ultrasound spectroscopy (RUS) is an emerging ultrasonic measurement technique. By measuring the natural vibrational frequencies of test samples, RUS can determine Young's modulus, shear modulus, and Poisson's ratio for isotropic materials. By comparing the vibrational spectra of a test sample to those obtained from a standard, it is possible to infer the causes of the differences (if any) and detect various part defects, such as size variations, cracks, and pores. Thanks to advances in computer technology, codes and software are now available for data reduction, analysis, and interpretation. This article addresses fundamentals of the technology and applications in research and industry.

This article provides an overview of nondestructive test methods and their application in the study of material properties and structures. It covers the most widely used NDT technologies, including optical examination, radiography, acoustic emission, and ultrasonic testing, and discusses the impact of recent advancements.