Measurement of Full Field Strains in Filament Wound Composite Tubes Under Axial Compressive Loading by the Digital Image Correlation (DIC) Technique
Abstract
The undulated fiber architecture inherent in filament wound polymer matrix composite cylinders presents challenges in predicting fiber direction modulus and strength using traditional micromechanical theories. Therefore, experimental characterization of the micromechanics of fiber micro-buckling in a filament wound composite tube in compression is necessary for using this class of composite in design. A [+-theta/89/+-theta] tube specimen was devised for the express purpose of evaluating the compressive strength and elastic modulus of the composite material in the fiber direction properties that are believed to be strongly affected by fiber undulations. Composites made with carbon fibers and a flexible polyurethane matrix were evaluated. Three-dimensional digital image correlation was used to measure in plane strains as well as radial displacements. A strong dependence on filament winding pattern (FWP) was found in xx, yy, and xy, as well as dR/dt, the change in the radius with respect to time. The filament wound tubes investigated here required a spatial resolution of approximately 16 pixels/mm in order for the FWP to be resolved in the strain field. If only radial displacements are of interest, a lower resolution may be used.
Document Details
- Document Type
- Technical Report
- Publication Date
- May 01, 2013
- Accession Number
- ADA584790
Entities
People
- Charles E. Bakis
- Jaret C. Riddick
- Ryan P. Emerson
- Todd Henry
Organizations
- United States Army Research Laboratory