Study on the Fracture Toughness of Hydroxyl-Terminated Polybutadiene Solid Rocket Propellant

摘要

The present work is aimed at studying the fracture behavior of a hydroxyl-terminated polybutadiene solid rocket propellant A fracture mechanics method based on the J integral was adopted to evaluate the material's resistance against crack initiation and propagation with the auxiliary of a high-speed microscopic camera and multiple-sample test procedure. The discrete data of load, displacement, and fracture energy at different crack initiation points and crack growth amounts were well fitted by the least-squares method and binomial method. The crack initiation J integral J_C = 1.8523 kJ/m~2 was determined, and the apparent initiation fracture toughness J_(IC) = 1.9533 kJ/m~2 was obtained by the blunting line and J-R curve. Furthermore, a crack-propagation velocity curve was obtained, and the damage mechanism of the crack-tip zone and its influence on the crack propagation were investigated.