Fracture Toughness of Space Shuttle Foam

Abstract

Fracture toughness of the rigid, low-density, closed-cell, polyurethane, foam used for insulation on the Space Shuttle External Tank is investigated. Data were obtained by loading double-edge-notched specimens in tension. To account for the anisotropic nature of the foam, two types, of specimens were tested so as to represent fracture properties along two different material directions. Additionally, for each type of specimen, two different notch sizes were tested.