HIGH STRAIN-RATE TESTING FOR CHARACTERIZATION OF ABLATOR MATERIALS

摘要

This paper describes the experimental test programs involved in the materials characterizations of NASA (National Aeronautics and Space Administration) Shuttle fleet ablator materials. Although these materials are used as thermal protection of the Shuttle external tank, their high speed impact properties are required as part of the safety studies for NASA. Experiments are detailed where the properties of these materials were determined at a variety of strain-rates to provide data for the analysis based safety studies. Due to the speed of the tests, videographic means were necessary to determine the deformation of the test specimens. Insights gained from these tests show that these ablator materials are highly strain-rate sensitive; some materials showed factors of 3 increases in strength for 2 decades of strain-rate increase. These properties have been used in the NASA Wing Leading Edge Sensor analytical database to determine expected Shuttle responses during impacts of such materials.