Effects of Partial Interlaminar Bonding on Impact Resistance and Loaded-Hole Behavior of Graphite/Epoxy Quasi-Isotropic Laminates.
Abstract
An interlaminar weakening concept that was developed to improve fracture toughness of composites was evaluated for its effects on resistance to impact and for behavior around a loaded hole. Mylar sheets with 25- and 15-percent perforations were interleaved between 24 composite prepreg layers. Specimens were impacted by 13-mm-diameter aluminum spheres while under tensile or compressive loads. Failure thresholds and residual strengths were obtained. The loaded-hole specimens were tested in three configurations: bearing critical, shear critical, and tension critical. Ultrasonics and X-radiography were used to detect damage. The tensile and compressive strengths of undamaged specimens were reduced by 36 and 30 percent, respectively, by partial bonding. Partial bonding reduced by 50 percent the velocity of impact that could be survived while under compression. Also under compression, the prestrain threshold level for failure was about one-half that under tension for all bonding percentages. Little benefit of partial bonding was uncovered for tension, and serious degradation occurred for compression.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jul 01, 1986
- Accession Number
- ADA302017
Entities
People
- Walter Illg
Organizations
- Langley Research Center