Experimental study of collision between a free-free beam and a simply supported beam

Recently, the authors and others have theoretically modeled and comprehensively analyzed the beam-on-beam collision (Yu, et al., Int J Solids Struct 28 (2001) 2001; Ruan et al., Int J Solids Struct 40(12) (2003) 2937-2956; Ruan and Yu, Int J Mech Sci 45(3) (2003) 397-423), as typical examples of collisions between two deformable structures. Particular attention was paid to the energy partitioning in the two colliding beams as well as in the local contact deformation. In order to verify these theoretical models, experiments were conducted on the collision between a flying free-free beam and a stationary simply supported beam. The free-free beam was accelerated by a bullet ejected from an air gun. The energy dissipation was calculated based on the residual flexural profiles of the colliding beams. It is found that most of the curvature change concentrated in the middle portions of the two beams, indicating that most of the plastic deformation occurred in their mid-spans. This fact justifies the modal solution. The energy dissipation ratio of the two beams obtained from the experiments shows a good agreement with the theoretical predictions, verifying the theoretical models previously developed. The contact areas were also clearly identified and measured. The comparison with theoretical modal proposed in Ruan and Yu, Int J Mech Sci 45(3) (2003) 397-423 shows that the Blunt Indentation model is the best one while the elastic response is not negligible if the local deformation is concerned.