Improving the D2512 Lox Compatibility of Composites by Using Thermally Conductive Graphite Fibers
Abstract
This effort demonstrated that using a thermally conductive fiber substantially enhances a composite's ASTM D2512 mechanical impact liquid oxygen compatibility. It repeatedly achieved 90% of the goal of passing D2512 with a 1700% improvement over baseline. This effort also documented the types of fracture surfaces routinely found in the residuals of the materials investigated. These fracture surfaces indicate that hertzian fracture is the mechanism by which a specimen fractured and failed. The fracture surfaces routinely indicated that kinetic friction associated with signs of intense heating occurred. Kinetic friction's mechanical-to-thermal transformation mechanism provided the only phenomenological explanation for the extremely rapid and large temperature rises required for conditions recognizable as ignition to occur in the time frame of a D2512 test. The effort crystallized the sequence from fracture to heating to ignition. First, a series of hertzian fractures develop. These allow kinetic friction of the hertzian fractured material to occur. Kinetic friction transforms mechanical energy into temperature rising thermal energy. This thermal energy causes the material to degrade by radical chain scission and oxidize by radical addition peroside chemistry to a degree detectable as ignition.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 01, 2005
- Accession Number
- ADA443342
Entities
People
- Roger Gerzeski
Organizations
- Air Force Research Laboratory