Chimera Ablative Tensile Screening - November 26th, 2024
The first tensile run tested 19 dog-bone specimens: a pure-epoxy control and epoxy samples containing glass microballoons, alumina powder, milled glass fibre or sodium bicarbonate. The samples covered multiple additive concentrations.
The material review records that glass microballoons made the uncured epoxy substantially thicker and difficult to pour. Milled glass fibre was easier to pour and was included as reinforcement. Alumina was included for heat resistance and matrix strength; sodium bicarbonate was included as a gas source for transpiration cooling.
Result and limits
Each formulation had one specimen. Several samples contained bubbles or concave sections, and the pure-epoxy control reached only about half the manufacturer's stated tensile strength. The measurements were therefore screening data, not statistically sufficient material properties.
No formulation was selected from this test. The test record required repeated controls, ablation testing and defined engine loads before a down-selection. The January 2025 PDR likewise states that more tests were required.
