The issue of weak initiation of a plastic binded high explosive arises in an accident scenario. A damaged explosive is much more sensitive to initiation than when it is in pristine condition. The enhanced sensitivity results form the formation of hot spots in conjuntion with the temperature sensitivity of the reaction rate.
Hot spots are localized regions of high temperature.
They can result from a variety of mechanisms, such as plastic work, frictional heating or pore collapse. Hot spots can however be studied numerically by applying continuum mechanics models to a small sample of the material. These highly resolved computations are known as micro-mechanical simulations. A granular explosive has an extra degree of freedom associated with porosity and can be used to represent a damaged material. Stress concentrations arise at the contact between grains.