Unique Fiber Optic Sensor System for Residual Stress Measurement on Graphite Composites.
Abstract
Virtually every composite fabrication process inherently results in the presence of residual strain in the component produced. Residual strain can result in warping and distortion of the finished part and seriously affect the component mechanical response to service loads. Measurement of this strain through the thickness of a composite is not a trivial task. Foster-Miller has developed the basis for a residual strain measurement system utilizing embedded fiber optic Bragg grating technology. Based on a novel tooling concept and advanced processing procedure, standard Bragg grating sensors were embedded through the thickness of flat plate and angled beam components and cured in place. Two conditions of residual strain were measured: strain due to thermal effects induced by the cure cycle and strain imparted into the composite by post%ure machining operations such as sectioning and drilling. It was proven that the embedded sensors could measure through-thickness tensile and compressive strain changes induced by various machining operations. It was also shown that residual strains due to thermal effects could be measured in high strain angled beams and that these strains correlated well to theoretical values predicted by finite element analysis.
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 01, 1995
- Accession Number
- ADA367093
Entities
People
- D. Bullock