Reference Installation for Complex Measurements of the Acoustic Parameters of Solids

The challenges of providing national metrological organizations with category 1 working standards are considered with regard to the current needs in the field of reference ultrasonic measurement in solids. An upgraded reference installation is presented for performing precise measurements of the propagation velocities of longitudinal and shear ultrasonic waves, as well as the damping coefficient of longitudinal ultrasonic waves in solids. Measurements of the acoustic parameters of solids are performed by pulse-echo and resonance methods using contactless broadband capacitance methods of excitation and registration of ultrasonic waves. This installation is used as a category 1 working standard in accordance with the State verification schedule for the instruments designed to measure the propagation velocities and damping coefficient of ultrasonic waves in solids. The technical instruments included in the installation (mechanical and electronic parts) have been upgraded, analog measuring devices have been replaced with digital ones, methods for measuring the acoustic parameters of solids based on the use of digital measuring instruments have been developed, and the thickness range of installed ultrasonic standards has been expanded. The composition and main components of the reference installation along with the used measurement methods and principles of operation of the installation under various operating conditions are described. The technical and metrological characteristics of the installation are provided. The sources of measurement error (uncertainty) have been analyzed. The field of application of the results includes high-precision measurements of the acoustic characteristics of solid media, as well as metrological support of ultrasonic nondestructive testing and diagnostics.