Accession Number : ADA303696

Title :   The Immersed Fatigue Response of Polymer Composites.

Descriptive Note : Contract technical rept. 1 Oct 92-1 Feb 96,

Corporate Author : TENNESSEE UNIV KNOXVILLE DEPT OF MECHANICAL AND AEROSPACE ENGINEERING

Personal Author(s) : Smith, L. V. ; Weitsman, Y. J.

PDF Url : ADA303696

Report Date : 02 JAN 1996

Pagination or Media Count : 28

Abstract : The effect of sea water on carbon/epoxy cross ply specimens is studied by consideration of fatigue data and failure modes. Tests were conducted using dry and saturated coupons fatigued in air, as well as pre-saturated coupons fatigued while immersed in sea water. The saturated coupons fatigued in air had the longest fatigue life, which was attributed to stress relief from sorption induced swelling. Saturated coupons fatigued in an immersed environment exhibited the shortest fatigue life, and also experienced significant delaminations prior to failure. Water trapped inside the transverse cracks during the load cycle provides a physical mechanism explaining this behavior. An analytical and numerical analyses are presented which show how moisture inside the transverse cracks can alter the coupon stress state and enhance delamination. (MM)

Descriptors :   *FATIGUE LIFE, *POLYMERS, *EPOXY COMPOSITES, STRESS ANALYSIS, COMPOSITE MATERIALS, FINITE ELEMENT ANALYSIS, STIFFNESS, CRACKS, DISPLACEMENT, STRAIN(MECHANICS), CARBON, MOISTURE CONTENT, SATURATION, SHEAR STRESSES, LIQUID IMMERSION TESTS, FAILURE(MECHANICS), SEA WATER, IMMERSION, DELAMINATION, TENSILE TESTERS, FATIGUE TESTS(MECHANICS), CYCLIC LOADS.

Subject Categories : Laminates and Composite Materials
      Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE