Examination of the Stress--Strain State of Composites by the Ultrasonic Nonstationary Frequency Method [Previously Titled: Stress--Strain Investigation of Composites by an Unstable Frequency Method.]

Previously abstracted from the original as item 9005-B2-D-0278. For investigating and evaluating the stress--strain state (SSR) of composites it is proposed to use an ultrasonic unstable-frequency (UF) method based on the dependence of the speed of propagation of ultrasonic vibrations (USV) on the SSS of a specimen or article. The results of an UF study of the shift of USV with uniaxial loading of specimens of different composites are presented. The sensitivity and resolution of the UF method were evaluated and found to permit recording of reliable variations in USV velocity at the level of 10 exp --5 and the corresponding stress changes of 10 exp --3 of the limiting values corresponding to them.