Chapter 7. Instrumented Hertzian Indentation of Armor Ceramics

Summary

There is commonality between the resulting damage in ballistically tested ceramics and Hertzian indentation. In an effort to study the parameters associated with the damage from the latter, a new-instrumented indentation test system was fabricated to facilitate the evaluation of (typically very hard) candidate armor ceramics. The indentation results from the testing with this system indicate that the utilization of: a diamond indenter; ultra high-resolution displacement measurement; a controlled loading/unloading waveform; and a simple mechanical analog model can be used in combination to quantify quasi-plastic yield and ring-crack initiation stresses that may be subsequently used to generate a plasticity-fracture map all with a single indent. A description of the test system and the indentation testing and evaluation of a hot-pressed SiC are presented.