ABL and BAM Friction Analysis Comparison

The Integrated Data Collection Analysis (IDCA) program has conducted a proficiency study for Small-Scale Safety and Thermal (SSST) testing of homemade explosives (HMEs). Described here is a comparison of the Alleghany Ballistic Laboratory (ABL) friction data and Bundesanstalt fur Materialforschung und -prufung (BAM) friction data for 19 HME and military standard explosives. Two methods were employed to reduce the data – modified Bruceton analysis (F50) and the threshold initiation level analysis (TIL). The study provides a full list of friction sensitivity data for the 19 materials by both ABL and BAM friction testing equipment. Specific results highlight the differences more than the similarities of the two methods. PETN and KClO3/sugar mixtures exhibit the most sensitivity of the materials studied by both testing methods. On the other hand, H2O2/fuel mixtures exhibit no sensitivity in ABL testing, but exhibit some sensitivity in BAM testing. For the UNi mixtures, the behavior was the opposite, no sensitivity in BAM but some sensitivity in ABL. KClO4/Al mixtures exhibit high sensitivity in the ABL method, but only moderate sensitivity in the BAM method. Other differences are seen in the relative sensitivities underscoring the differences in the mechanisms of how each test method operates. In some cases, data could not be attained because of the physical nature of the material. Comparison between the two friction methods on a material-by-material basis using absolute values not surprisingly yielded essentially no systematic correlations. Even the relative order showed little correlation between the two methods. The Department of Homeland Security (DHS) funded this effort. Each participating testing laboratory uses identical test materials and preparation methods. However, the test procedures differ among the laboratories. The testing performers involved are Lawrence Livermore National Laboratory (LLNL), Los Alamos National Laboratory (LANL), Naval Surface Warfare Center, Indian Head Division Explosive Ordnance Disposal Technology (NSWC IHEODTD), Sandia National Laboratories (SNL), and Air Force Research Laboratory (AFRL/RXQL).