2016 Volume 1 Pages 161-166
In a high-precision work, the workpiece is ground by a high-speed-spinning abrasive wheel. When the abrasive wheel is fractured due to operator error or malfunctioning, the fragments of the abrasive wheel fly apart at a high speed. Therefore, a shatterproof cover must be designed to ensure safety and prevent the collision of fragments. In this study, we investigated the collision of an abrasive projectile against a steel sheet, using a large-scale launching system. In this test, three projectiles of mass of 2.08 kg, 3.4 kg and 6.75 kg, and a SS400 steel sheet of size 750 mm × 750 mm, were used. The test results revealed three different patterns: fracture with penetration, fracture without penetration and non-fracture. From those results, we determined that the collision energy as a result of the fracture without penetration served as the boundary value, with and without penetration. In addition, assuming that the projectile and the target were a rigid body and a rigid-perfect plastic solid, the bending energy, E, was found to vary as the second power of the steel sheet thickness. Thus, it was clarified that E coincided with the predicted boundary values. This suggested that the collision phenomenon of the abrasive projectile against the steel sheet can be evaluated using the collision energy.
