Experimental investigation of fracture surface energy of a solid propellant under different loading rates

Fracture tests on solid propellants have been performed under three ranges of loading rate leading to fracture toughness results in terms of J_IC and (Andrews' parameter). Using two different specimen shapes, finite size effects have been pointed out (considering SENT sample) when dealing with Andrews' theory and a modified equation, taking into account the specimen compliance, is proposed. Significant influence of loading rate on J_IC is observed leading to few conclusions concerning fracture process of solid propellants.