Nuclear Weapon Yield Determination through Nano Indentation of Thermally Degraded Automobile Paint

This work investigated the suitability of automotive clearcoat as a nuclear weapon yield sensor, using the change in elastic modulus as the primary metric. The AFIT Xenon Thermal Simulator (AXTS) was used to simulate a nuclear thermal pulse. The elastic modulus of the clearcoat was measured using a nano indenter. During this research the power density of the AXTS beam was increased from 44.7 to 63.7 W/cm2. The morphological steps through which automobile paint proceeds as it thermally degrades were identified and correlated with temperatures. A computer model was created and used to ensure that the paint's time-temperature response to the AXTS pulse was comparable to that of a replicate nuclear thermal pulse. Clearcoat's physical properties exhibit a low sensitivity to incident thermal energy. Variability among these properties remains essentially unchanged by exposure to the thermal pulse. A weak correlation between change in elastic modulus and exposure time was identified. A similarly weak correlation between exposure time and each of load on sample, harmonic stiffness, and hardness was also identified. It was concluded that these correlation were too weak to be used for post-detonation forensics.