L-227 Probabilistic Aspects Of Munition Initiation Due To Fragment Impact

A probabilistic analytic model of initiation for the Insensitive Munitions (IM) Fragment Impact test was developed. The deterministic Jacobs-Roslund detonation initiation model was augmented to include impact point offset and projectile tilt against a curved munition case. This augmentation was based on geometrical aspects of the shock produced by impact. The model was calibrated using the 1-D hydrocode, GODLAG. The velocities and thicknesses of the 1-D GODLAG impactors were based on matching peak pressures and pressure histories from previous fully 3-D fragment impact hydrocode modeling. State of the art probability tools were subsequently used for variational impact conditions using the newly developed analytic IM FI explosive initiation model. The varied parameters included the impactor velocity, tilt, impact position offset and tilt. The results showed a large reduction in initiation probability.  This reduction in initiation probability was primarily due to the impact position offset.