When a building is detonated, the debris generated collides with the ground with very high energy and bounces back. This phenomenon is called ricochet. Ricochet increases risk by increasing the moving distance of the debris. The ricochet of debris is affected by the shape of the debris. In this paper, the behavior and moving distance of debris along the shape of debris were studied. For various initial conditions, the ricochet of debris was studied through the FEM, and the results were fitted to a 3D curved surface to predict the speed and angle after the ricochet. The moving distance of the debris was calculated using the trajectory formula considering the drag coefficient using the MATLAB. The ricochet of debris is affected by the contact area with the medium. As the contact area increases, the reflection angle increases because of the increase of the repulsive force. As the size of the debris increases, the energy loss also increases because of the increasing of the contact area. Thus, the moving distance of the cylinder debris is shorter than that of the sphere debris.

When a building explodes, debris generated bounces after hitting the ground with high energy. It is called the ricochet phenomenon. Ricochet phenomena increase the risk of damage by increasing the moving distance of the debris. The ricochet of debris is impacted by the type of medium. In this paper, the behavior and travel distance of debris after ricocheting are studied according to the type of medium. For various initial conditions, the ricochet of the debris was studied through FEM, and the resulting values were fitted to the 3D curved surface, to predict the speed and angle after the ricochet. The trajectory of the sphere was calculated with the flight formula, considering drag force by using the MATLAB. The ricochet of debris is impacted by the contact area with the medium. As the contact area increases, the reflection angle increases due to the increase of the repulsive force. As the size of the debris increases, the contact area increases and the energy loss increases, but it moves further because of the increase of the weight and kinetic energy. The type of media around the building can be used as an appropriate means of controlling the travel distance of the debris.