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Title: Simulations of defense strategies for Bennu: Material characterization and impulse delivery

Assessments of asteroid deflection strategies depend on material characterization to reduce the uncertainty in predictions of the deflection velocity resulting from impulsive loading. In addition to strength, equation of state, the initial state of the material including its competency (i.e. fractured or monolithic) and the amount of micro- or macroscopic porosity are important considerations to predict the thermomechanical response. There is recent interest in observing near-Earth asteroid (101955) Bennu due to its classification of being potentially hazardous with close approaches occurring every 6 years. Bennu is relatively large with a nominal diameter of 492 m, density estimates ranging from 0.9-1.26 g/cm³ and is composed mainly of carbonaceous chondrite. There is a lack of data for highly porous carbonaceous chondrite at very large pressures and temperatures. In the absence of the specific material composition and state (e.g. layering, porosity as a function of depth) on Bennu we introduce a continuum constitutive model based on the response of granular materials and provide impact and standoff explosion simulations to investigate the response of highly porous materials to these types of impulsive loading scenarios. Simulations with impact speeds of 5 km/s show that the shock wave emanating from the impact site is highly dispersivemore » and that a 10% porous material has a larger compacted volume compared with a 40% porous material with the same bulk density due to differences in compaction response.« less
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  1. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Publication Date:
OSTI Identifier:
Accepted Manuscript
Journal Name:
Procedia Engineering
Additional Journal Information:
Journal Volume: 103; Journal Issue: C; Journal ID: ISSN 1877-7058
Research Org:
Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States)
Sponsoring Org:
Country of Publication:
United States
36 MATERIALS SCIENCE; 79 ASTRONOMY AND ASTROPHYSICS Bennu; constitutive modeling; material characterization; asteroid deflection; Eulerian hydrocode