Accession Number : AD0768614

Title :   Effects of Cyclic Frequency on the Mechanical Properties of Composite Materials.

Descriptive Note : Interim technical rept.,

Corporate Author : VIRGINIA POLYTECHNIC INST AND STATE UNIV BLACKSBURG COLL OF ENGINEERING

Personal Author(s) : Stinchcomb,Wayne W. ; Reifsnider,Kenneth L. ; Marcus,Larry A. ; Williams,Richard S.

Report Date : JUN 1973

Pagination or Media Count : 38

Abstract : Strain controlled cyclic stress-strain and fatigue tests are conducted on specimens of boron-epoxy and boron-aluminum at cyclic frequencies between 0.5 Hz and 45 Hz. The specimens are cross-ply laminates with a (0 degree, plus or minus 45 degree, 0 degree), fiber orientation and have a 0.25 inch hole in the center. The results of data obtained from both types of tests show the response of the material to be frequency and cycle dependent. The marked difference in behavior of the material at 15 Hz and 30 Hz suggests the presence of a transition frequency (or frequency range) at which the properties of the material are greatly influenced by frequency controlled mechanism. At a given frequency, changes in properties occur with increasing cycles and correlate with acoustic emissions monitored during the test. (Author-PL)

Descriptors :   (*COMPOSITE MATERIALS, FATIGUE(MECHANICS)), BORON, ALUMINUM ALLOYS, EPOXY RESINS, LAMINATES, FREQUENCY, ACOUSTIC PROPERTIES, DAMPING

Subject Categories : Laminates and Composite Materials
      Test Facilities, Equipment and Methods

Distribution Statement : APPROVED FOR PUBLIC RELEASE