Volume 10, Issue 5 (September 1982)
Ultrasonic Measurement of Residual Stress in Textured Materials
A method is developed that determines the state of stress in a test piece in the presence of texture, that is, preferred grain orientation. This method uses frequency domain analysis of the acoustic birefringence by which an ultrasonic shear wave propagating in a material travels at slightly different velocities in the polarizations parallel and perpendicular to the axes of texture or stress. Results obtained from a Ti-6%Al-4%V block confirm that the velocity shift is linearly dependent on the amount of stress, but is independent of frequency in the case of stress as opposed to the texture. Experimental considerations involving transducer characteristics, bond (transducer to specimen) characteristics, specimen size, and signal processing are discussed in relation to the reliability and repeatability of the data.