O-035 A New Approach to Assessment and Design of Insensitive Munitions by Analysis of Critical Mechanisms that may be Initiated by Unplanned Stimuli

November 1997
Andrew J. Sanderson (Energetic Materials)

It is easy to prove that all up round (AUR) safety and insensitive munitions (IM) tests by themselves give little or no reliable information about the item under test unless conducted on large numbers of items. This of course is usually prohibilively expensive. However, reliable IM and safety assesments are required and it is not possible to comprehensively model these tests using computer codes or to directly correlate any small scale (laboratory) tests to the AUR tests.

Despite the problems with testing and modelling, it is frequently possible for someone familiar with the subject to fairly reliably guess the response of a munition to the IM tests. In addition, as you can state the assumptions on which the guess is made, you have a good idea how confident you can be in your guess.

A solution to the need to make safety/IM assessment given these facts, is to use expert knowledge in a formal/auditable way in conjunction with appropriate modelling and laboratory tests. This leads to greatly increased confidence in assessment, and at the same time eliminates or reduces the amount of AUR testing needed.

This paper discusses present testing methods and proposes an improved alternative method for IM assessment that makes maximum use of currently available modelling and laboratory testing technology. This method is based on risk assessment methods and an analysis of the Critical Reaction Initiation and growth MEchanismS (CRIMES) that may cause munition responses in IM tests. With knowledge of the CRIMES, the tests, modelling and analysis necessary to determine the responses of the AUR to the stimuli are identified. Response severity is then determined from modelling and small scale tests. Although IM testing is used as the example here, the method could be applied to any explosive safety assessment.
The advantages of this approach include:

  • prior knowledge of exactly what data will be needed for the assessment of a munition from the design stage;
  • greatly increased confidence in the final munition behaviour assessment;
  • cheaper assessment;
  • knowledge of the reliability of the results;
  • the possibility of stating simple requirements that allow for the complexities of reality.

Presentation details

Paper presented at the PARARI 97 Symposium held on 12-14 November 1997 in Canberra, Australia