Effect of copper tube quality on the cylinder expansion test results

Abstract. Cylinder expansion (CYLEX) test is a common technique for characterization of metal acceleration capability of energetic materials. Usually, the CYLEX tests are done in oxygen-free copper tubes (Cu-OFE). In this paper, the results obtained with Cu-OFE and the more common Cu-DHP tubes are compared. The CYLEX tests were performed with nitromethane sensitized by the addition of 1, 5, 10 and 15 % of 1,2-diamminoethane. The wall velocities were measured using photonic Doppler velocimetry. Two probes were used per each tube allowing the detonation velocities to be determined simultaneously. These two types of copper tubes provided quite similar results. The Gurney velocities obtained with Cu-DHP tubes were slightly higher compared to Cu-OFE tubes. Quantifying the difference between available copper tubes allows for optimizing future testing procedures. The results were also compared with predictions obtained using the EXPLO5 code.