Anomalous swelling behavior of FM 5055 carbon phenolic composite

Abstract

Carbonized rayon-based phenolic composites are used extensively as ablative surfaces in the design of aerospace hardware. Historically, their performance has been inconsistent. Many of the anomalous events documented to occur in these materials can be traced to the material's volatile constituents. The largest volatile component (>80%) is known to be water. Water not only acts as a pore pressure producing gas but has been shown to plasticize cured phenolic resins. The location of water within the material and the relative hydroscopic tendencies of the various components of the composite are of interest in understanding the mechanism of these various anomalous events. This study measured the swelling response of a typical carbon phenolic composite in the three primary material directions