Accession Number : ADA306173

Title :   The Effect of Stress on Ultrasonic Pulses in Fiber Reinforced Composites.

Descriptive Note : Contractor rept.,

Corporate Author : CLEVELAND STATE UNIV OH

Personal Author(s) : Hemann, John H. ; Baaklini, George Y.

PDF Url : ADA306173

Report Date : AUG 1983

Pagination or Media Count : 80

Abstract : An Acoustical-Ultrasonic Technique was used to demonstrate that relationships exist between changes in attenuation of stress waves and tensile stress for an 8-ply '0' degree graphite-epoxy fiber reinforced composite. All tests were conducted in the linear range of the material for which no mechanical or macroscopic damage was evident. Changes in attenuation were measured as a function of tensile stress in the frequency domain and in the time domain. Stress wave propagation in these specimens was dispersive, i.e., the wave speed depends on frequency. Wave speeds varied from 267400 cm/sec to 680000 cm/sec as the frequency of the signal was varied from 150 KHZ to 1.9 MHZ which strongly suggests that flexural/Lamb wave modes of propagation exist. The magnitude of the attenuation changes depended strongly on tensile stress. It was further observed that the wave speeds increased slightly for all tested frequencies as the stress was increased. (MM)

Descriptors :   *ACOUSTIC WAVES, *FIBER REINFORCED COMPOSITES, *GRAPHITE EPOXY COMPOSITES, VELOCITY, TENSILE STRESS, ULTRASONICS, WAVE PROPAGATION, ALUMINUM, ATTENUATION, TRANSDUCERS, TIME DOMAIN, FREQUENCY DOMAIN, STRESS WAVES.

Subject Categories : Laminates and Composite Materials
      Acoustics

Distribution Statement : APPROVED FOR PUBLIC RELEASE