Development of a collision model for mine clearing darts

This paper describes the development of a collision model for mine clearing darts and its implementation in a six-degree-of-freedom (6-DOF) code for predicting dart trajectories from dispense to ground impact. Previous 6-DOF simulations did not include dart collisions but only mimicked its effects by initializing the darts with random tipoff angles. These simulations provided good predictions of dart impact pattern size and density distribution when compared with flight test data. However, the impact velocity distribution was poorly predicted. To improve results for impact velocities, a collision model is implemented and presented here. The collision detection is based on the algorithm of [1] for collisions between finite circular cylinders. By treating the darts as cylinders, geometric features can be exploited for quicker detection, which is very important for keeping the simulation time to a reasonable level. Additional efficiency is achieved by dividing the darts into overlapping rectangular bins. The collision search is performed for dart pairs in individual bins instead of searching the entire dart cloud. With collision modeling implemented, the 6-DOF now provides excellent agreement with flight test data for impact pattern size, density and velocity distribution.