Effect of Different Rock Models on Hydrocode Simulations of Asteroid Airburst and Impact Blast

Abstract:

Ground damage estimates from airburst or ground impact of asteroids depend on the shock waves and blast winds emitted. While semi-analytic models exist and hydrocode simulations of cratering are well studied, there is very little literature on the blast waves from asteroids hitting the Earth. The blast waves depend strongly on the energy deposition rate, which in turn depends on the break-up mechanics of the asteroid either during atmospheric entry or on the ground.

This presentation will examine the effect of different rock models on the break-up and energy deposition. The simplest models can assign a single rock strength, chosen to match the burst altitude of previously observed airbursts. Such simple models can provide energy deposition curves that match observations reasonably well, but are not representative of the behaviour of real rock masses. We will compare the failure mechanisms and energy deposition of more sophisticated models including effects such as more realistic yield surfaces that account for tensile, shear, and compressive failure strengths, and size dependent features such as cracks, strength distributions, porosity, and variations in internal composition.