Fractographic Analysis of Optical Fibers
Abstract
The fracture surfaces of over 50 fibers tested at Hughes or ITT reasearch Laboratories were examined on the scanning electron microscope (SEM). The sources of failure in these fibers were determined to be either mechanically induced sharp cracks, cracks resulting from inclusions or foreign particles, bubbles or inclusions. It was suggested that many of these sources of failure can be eliminated by changing production procedures. For example, some larger inclusions can be eliminated by using synthetic, high grade silica, starting material. Another example for eliminating low strength defects is by using high quality silica tubing in the CVD process. The fracture surface demarcations known in glass as mirror, mist, hackle, and crack branching were identified and related to the stress, at failure. In all cases but one, fracture surface analysis agreed with measured stresses during testing within experimental accuracy. Thus, fractography can be used to determine the stress and source of unexpected service failures.
Document Details
- Document Type
- Technical Report
- Publication Date
- Nov 01, 1977
- Accession Number
- ADA078862
Entities
People
- J. J. Mecholsky
- S. M. Morey
- S. W. Freiman
Organizations
- United States Naval Research Laboratory