Fatigue Damage Behavior in Composite Materials.
Abstract
Detection of early fatigue damage in composite materials by nondestructive inspection (NDI) techniques has been demonstrated for plus or minus 45 degrees Glass/Epoxy, and plus or minus 45 degrees/0 degrees Graphite/Glass/Epoxy. Dynamic axial modulus and temperature were monitored continuously with a correlation between temperature rise and modulus decrease observed. The modulus decrease and temperature rise are indicative of irreversible damage in these materials. This is validated by observation of a rapid restoration of elevated temperature after reloading specimens which had been stopped and had cooled to ambient temperature. Torsional modulus measurements and coin tap tests were performed at 0, 1,000,000, 5 x 1,000,000, and 10 to the 7th power cycles, on all fatigue specimens. Other NDI procedures including holographic interferometry, ultrasonics, penetrant, and X-Ray radiography were performed on two specimens of each material to evaluate their effectiveness in detecting fatigue damage.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 01, 1974
- Accession Number
- ADA001944
Entities
People
- John J. Lucas
- Joseph J. Nevadunsky
- Michael J. Salkind
Organizations
- United Aircraft Corporation