Prediction of Progressive Decomposition in Launching Space Vehicles Subject to Soft Foreign Object Impacts

Reusable space vehicles are subjected to high velocity to ballistic foreign object impact (FOI) events, particularly soft impacts. Such events and their consequent severe dynamic loading/unloading conditions occur during the launch phase or landing approach of the re-entry vehicles within their tropospheric flight windows. Effective prediction of non- linear dynamic responses of such structures, accentuated by the intricacy of the transient solid-fluid behavior of the projectile, can play a major role in developing a fail-safe design for these vehicles. A resulting crashworthy design can materialize through active control of the failure sequencing of the primary and secondary components. Two major discretized fluid-solid approaches, Smooth Particle Hydrodynamics (SPH) and Arbitrary Lagrangian-Eulerian (ALE), will be compared and presented which enable the effective prediction of complicated phase transition in the projectile. While the focus will be given to the SPH approach, a novel coupled micro constitutive/cohesive finite element solution will also be introduced, enabling the multi-scale analysis of progressive degradation and disintegration in impacted advanced space composite (sub)structures.