Energy Threshold of Brittle Destruction for Carbon-Based Materials

Abstract

An analysis by means of numerical simulation of brittle destruction of carbon-based materials under experimental conditions at the electron beam test facility JUDITH is carried out. For the simulations a 3-dimensional model based on the destruction threshold enthalpy of 10 kJ/g is developed, in which a significant decrease of heat conductivity due to crack formation in CFC is taken into account. Calculated dependences of onset of brittle destruction as functions of absorbed power density as well as the depths of graphite erosion are in a rather good agreement with experimental results for isotropic fine grain graphite and carbon-fiber composite. The brittle destruction threshold of 10 kJ/g is confirmed for pulse loads lasting less than 100 ms, both for isotropic fine grain graphite and CFC.