Longitudinal Strength of Unidirectional Fibrous Composites.
Abstract
Theoretical and experimental investigation of the longitudinal strength ofunidirectional fiber reinforced composite has been performed. The fibers aretreated as having variable strength which results in fiber fractures prior tocomposite failure. The matrix is treated as a linear viscoelastic material.The size effect is included in the mathematical analysis and the proposedfailure mechanism agrees with observed failure geometry. The effect of lengthon strength is found to be very small. Unidirectional glass reinforced epoxyand reinforced polyester specimens with 60% VOLUME FRACTION OF FIBERS WERETESTED IN TENSION AT THREE TEMPERATURES (25 C, 78 C AND 130 C) and a widetime range; from creep (more than a month) to impact tests. The compositestrength under impact conditions was found to be about three times higherthan under static conditions. This increase in strength is due to the glassfibers, the strength of which is rate sensitive. Scattering of results is quitehigh (plus or minus 10% in strength values, and plus or minus 5% in modulivalues) and this is attributed to the structure of the composite materials.(Author, modified-PL)
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 01, 1970
- Accession Number
- AD0716629
Entities
People
- Assa Rotem
- Jacob M. Lifshitz
Organizations
- Technion – Israel Institute of Technology