TNO Defence Security and Safety, has conducted research in energetic material response to all kinds of impact related stimuli such as bullet-fragment and shaped charge jet impact, and sympathetic reaction scenarios. These investigations comprise laboratory scale and in-service munition testing as well as the development of engineering and simulation models.
Non-shock initiation and the response mechanism of explosives is rather complex. Several mechanisms can lead to severe reactions of munitions or even to a detonation reaction. The response of munitions to these stimuli depends strongly on the properties of these materials at onset and during an event.
Fragment and bullet impact laboratory experiments with semi-confined explosives have been performed to investigate the mechanisms leading to the obtained responses. Besides laboratory experiments, several bullet impact test series on in-service shells and propelling charges have been performed that can be used to validate the engineering models.
To estimate the response of munitions after bullet or fragment penetration/perforation, engineering models are under development. The main processes in this mechanism have been identified and implemented in a flow chart. At the moment, these process steps have been split into several smaller process steps and models have been developed, derived or combined and implemented in Excel spreadsheets or, in the case of more complex sets of equations, in Python or Mathcad codes. The combination of these process steps and models will give an estimate of the response of the munitions and can be compared with the above mentioned experimental results. This paper will present the results of several test series and explain the engineering approach estimating the bullet-fragment perforation/penetration response of munitions.