Comparison of Fracture Response of Preflawed Tubes Under Internal Static and Detonation Loading

Fracture experiments were performed on thin-walled and preflawed aluminum 6061-T6 tubes. Flaws were machined as external axial surface notches. The tubes were 1) statically loaded with oil, 2) statically loaded with nitrogen, and 3) dynamically loaded with gaseous detonations traveling at 2.4 km/s. The experiments were controlled so that comparisons could be made on sets of specimens with the same material, tube and flaw geometry, nominal loading amplitude, and flange supports, with the only difference being the dynamics of the loading. It was found that there is a significant difference in crack propagation behavior for the three types of loading. In this paper, fracture behavior will be discussed along with the fluid dynamics involved. The tubes were also instrumented with pressure transducers, crack detection gages, and strain gages so that data on loading, crack propagating speeds, and strain history can be compared.