Measurement of Displacement Around Holes in Composite Plates Subjected to Quasi-Static Compression.
Abstract
Contour maps of thickness changes were obtained for three quasi-isotropIc graphite-epoxy plates with central holes, loaded in compression. Thickness changes were determined for six load increments from nearly zero to within a few percent of the failure load. The largest change of thickness occurred near the hole but not at the boundary of the hole. Below 90% of the failure load, the thickness changes were nearly proportional to load. irregularities of thickness changes occurred in zones of compressive stresses and they were attributed to localized fiber buckling. A new optical technique was developed to measure thickness changes with high sensitivity. it utilizes a omparatively simple means of holographic interferometry on both sides of the specimen, followed by additive moire to obtain thickness changes as the sum of the out-of-plane displacements. Sensitivity was 0.0000125 in. per fringe order. The fringe patterns represent thickness changes uniquely, even when specimen warpage and consequent out-of-plane disp%a tents are very large. (MM)
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 01, 1986
- Accession Number
- ADA302022
Entities
People
- Anand Asundi
- Daniel Post
- John C. Duke Jr.
- Robert Czarnek
Organizations
- Virginia Tech