Abstract:
This paper details the critical role of Finite Element Analysis (FEA) using the software LS-DYNA in the investigation of the Space Shuttle Columbia accident. Following the discovery that foam from the external tank struck the left wing during launch, an Impact Analysis Team was formed to determine the severity of the damage. A significant challenge was the lack of material property data for the foam and the wing's Reinforced Carbon-Carbon (RCC) material at the high impact rates and specific atmospheric conditions of the event. The team developed and validated complex, non-linear material models that accounted for strain-rate effects and brittle failure through extensive physical testing. Concurrently, a highly detailed finite element model of the wing's leading edge was created, consisting of over 400 individual parts derived from CATIA models, Pro E models, and 2-D drawings. The complex assembly was efficiently connected using LS-DYNA's tied contact and joint constraint features. Initial simulations modeled the foam using Eulerian elements to replicate the observed "splattering" dust cloud , later progressing to more accurate Lagrangian element models. The FEA was instrumental in providing pre-test predictions that guided physical impact tests, showing excellent correlation between areas of high strain in the simulation and the actual damage location and severity, including the creation of a 16-inch hole in a test panel. The success of these analytical predictions led to the team's continued support for Return to Flight activities, expanding the FEA scope to include different types of debris and impact locations.
