Speaker
Description
With the ever increasing number of re-entries occurring year-on-year, accurate modelling of the entry process is a vital part of the drive for space sustainability. Both in terms of reducing the many unknowns of destructive re-entry and applications in satellite design according to the Design-For-Demise (D4D) paradigm. Of particular interest for D4D efforts is accurate resolution of explosive events as the dispersion of debris fragments caused by explosions can have a significant effect downstream casualty risk. Due to this interest, different methodologies for accounting for explosive events have been deployed by the re-entry simulation community. However, as a rule, they do not account for original object geometry.
The TransAtmospherIc flighT simulatioN tool (TITAN) is an open-source multifidelity tool that seeks to simulate re-entry across many computational domains, fidelity levels and modelling disciplines. In line with this logic and TITAN’s core functionality as a mesh-based tool it was considered desirable to explore fragment generation methods that incorporate information about original component geometry into the resultant fragments. Alongside this, recent work on the tool in areas of dynamic propagation and collision resolution have developed the capabilities necessary to model explosive events.
In this work a presentation of TITAN’s explosion model is provided. Fragments with complex geometry are generated after explosion through partitioning of the original component mesh according to a geometric statistics fragmentation approach. These individual fragments are then propagated as a debris cloud using adaptive time-stepping and binary search Time-of-Impact (ToI) prediction with multibody dynamics and interactions represented through an impulsive constraint-solving collision model.
After considering an exploratory simplified case, the model is applied to more realistic spacecraft re-entry contexts. An external case with an exposed tank such as would be seen on an upper stage rocket body is compared to an internal case where a tank explodes inside an enclosed bay. Downstream fragment dispersion is analysed as a result of such explosive events and ground impact footprint is also assessed.