Friction sensitivity tests effect

There seems to be a noticeable difference in the Ball Drop Impact results and this could be attributed to the inherent error associated with this relatively crude test for instance, the manner and precise location, at which the steel ball impacts the explosive particles can vary and lead to inconsistent results. Friction and electrostatic sensitivity was consistent across all of our batches of DBX-1 as well as PSEMC DBX-1 (Table 3) In terms of determining the effectiveness of a primary explosive, sensitivity tests results are generally only predictive in how to safely handle the material in order to determine if the explosive is practical or not, performance tests need to be done to see how well the material behaves in actual items, such as detonators. 

Tests were also conducted to determine the effect of temperature on the friction sensitivity of the same materials [16]. None of the primary explosives revealed any marked temperature effect however, the fact that no large temperature effect was observed led Copp et al. to conclude that the action of the apparatus was mechanical rather than thermal. 

KL) Anon, "Military Explosives", TM 9-1300-214/TO 11A-1-34 (1967). Chapter 5. Properties and Tests of High Explosives Sensitivity to Frictional Impact (pp 5 1 to 5-3) Sensitivity to Friction (5 3 to 5-6) Sensitivity to Frictional Impact (5-6) Sensitivity to Heat and Spark, which includes Explosion Temperature Test (5-6 to 5-9) Sensitivity to Initiation (5-9) Stability Tests, which include 75° International Test, 100° Heat Test, Vacuum Stability Test and Potassium Iodide—Starch Test (5 9 to 5-15) Brisance Tests which include Sand Test, Plate Dent Test and Fragmentation Test (5 15 to 5-18 and Fig 5 13 on p 5-19) Initiating Value (5-18 5-20) Sympathetic Detonation (5-20 to 5-21) Power which includes Heat of Explosion Test, Ballistic Pendulum Test and Trauzl Lead Block Test (5-21. to 5-24) Blast Effect (5-24 to 5-27) Cratering Effect (5-28 5 29) and Munroe-Neumann Effect (5-29 to 5 35)... 

A small amt of the expl was spread on a large stone table and then struck a glancing blow with a mallet made either of rawhide or beech wood. The expl was thus subjected to the combined effect of shock and friction. If the sample exploded, the test was repeated by hitting the expl a glancing blow with a broomstick held at an angle of 60° against the table, taking care that the movement of the stick is in the direction of its axis. If an expin were obtd, the test was repeated on a hard wooden table and finally on a soft wooden one. If an expl, other than those used for caps, detonators, etc exploded, even partly on soft wood, it was considered to be too sensitive for use (Compare with Torpedo Friction Test, described as quantitative test i, Fi g F22)... 

The results of the effects testing will be used to place the material in a hazard category based on NATO-UN classification scheme and when combined with the sensitivij y data will give the material an overall hazard classification. For example, a material which is foiind to be an intense fire hazard (consequence 1.3) and sensitive (Category B) to initiation by rubbing friction would be placed in class 1.3B. 

A typical standard friction performance (effectiveness) test for a passenger car brake usually includes the following measurements green and burnished effectiveness thermal fade and recovery speed, pressure, and temperature sensitivity water fade/recovery moisture sensitivity cold and static friction. These aspects of friction performance are discussed elsewhere in some detail. " The performance of an ideal friction material will be immune to changes in braking conditions. 

In order to measure bulk strength in the absence of confinement, as relevant to the stress conditions on the underside of an arch, a failure test is carried out after the formation stress is removed. This test reflects the failure conditions on the surface of an arch subjected to passive wall pressures generated by a mass flow hopper, and is measured by an unconfined failure test, as shown in Fig. 1.4. A column of material is compacted in a cylindrical cell and then subjected to axial loading after removal of the cell walls. This is a delicate operation, due to the sensitive nature of the samples and the effect of wall friction opposing the compacting forces. Frictional effects rapidly magnify with the length of... 

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