The final project addresses the development, production, and evaluation of a device for testing impact resistance. The device can launch steel balls with a diameter of 17 mm with required kinetic energy. The chosen concept for the acceleration of a ball in a steel tube with a certain excess uses compressed air. With the help of a magnetic field, the ball is held in position, so the ball works like a valve. The full opening of the valve occurs at the moment when the electric current supplying the coil is interrupted. Analytical calculations were used to dimension pneumatic components, as well as the length of the pipe and the coil. Experimental analysis shows that the requirements are met and that the reproducibility for testing is adequate. In the operating range from 0 to 7 bar, the device can launch a ball with a maximum kinetic energy of 110 J, which is 10 to 30 % lower compared to the calculated values.
|