Vibration Testing of Impact-Damaged Composite Laminates.
Abstract
A new test is described that can be used to measure changes in the vibration properties of impact-damaged composite materials. Impact-induced delamination was observed to significantly affect natural frequencies of vibration and damping properties in cross-ply graphite/epoxy laminates. Natural frequencies are shown to drop by as much as half of their original value, and modal damping ratios can increase by a factor of up to eight when large amounts of damage are present. A simple finite-element model of the damaged impact specimens was used to predict the effect of delamination on certain vibration properties. A comparison of the finite-element calculations with the experimental measurements suggests that delamination was the dominant mechanism of flexural stiffness loss resulting from the transverse impact.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 01, 1989
- Accession Number
- ADA310579
Entities
People
- Erwin H. Meyn
- Joseph E. Grady
Organizations
- Glenn Research Center