CRM has experience in both debris transport analysis and debris impact analysis. Analyst experience dates back to the 1990s when warhead damage assessment studies from KVs were performed for AMCOM (MICOM at the time), AMRDEC in Hunstville, Al.
More recently, CRM performed debris transport analysis simulations for the Ares vehicles. This was done with three levels of fidelity.
- Highest Fidelity: Use of one-way Chimera (OverSet) CFD technology with the Navier-Stokes CFD Solver Loci/CHEM. The background solution remains frozen while only the Chimera mesh encompassing the debris is resolved and integrated with the 6-DOF solver each time step
- Medium Fidelity: Use of an in-house developed tool using Quasi-Unsteady Inviscid adaptive CFD techniques that couples the Cart3D (FlowCart; NASA Ames) solver with an embedded 6-DOF to provide automated moving body simulation capability.
Lowest Fidelity: Use of a tool which queries frozen Navier-Stokes solutions, obtains local flow conditions, applies them to lift/drag coefficients of the debris, then updates position with coupled 6-DOF solver. Debris mass, shape and liberation velocity allows many trajectory points to be obtained quickly for existing CFD flight conditions. The customer can be provided with hundreds of thousands of debris strike candidates in a rapid fashion.
See the list of CFD publications for details of this work.
Debris Transport; High Fidelity (Loci-CHEM) vs Medium Fidelity (FlowCart)
Navier-Stokes One-Way Chimera Coupling Debris Predicted Motion
Lowest Fidelity: Rapid Debris Transport Predictions for Many Sources are Obtained, Bounded by the Green Cone
Additionally, CRM currently performs debris impact assessment on launch vehicles and defensive systems with use of the LS-Dyna Hydrocode. Current analysis includes prediction of thermal protection system loss from impact or possible breach of vehicle skin determination. Advanced models allowing for compression, plastic deformation, and erosion are employed.
Below, the video shows foam (blue) impacting the TPS (green) and launch vehicle surface (yellow).