부산대학교 도서관

The mechanical properties, especially load-deformation relations under quasi-static and impact loading, of golf balls have been investigated by experiments and numerical simulations. Dynamic compression tests have been conducted by the method that the ball is made to collide with the stress bar and the load-deformation curves are obtained by integrating the stress wave histories. The following results have been obtained. The load-deformation curves show non-linearity mainly due to geometrical factor and show hysteresis due to internal friction of the ball both under static and dynamic loading. The ratio of energy loss due to intemal friction to input energy increases with the amount of deformation. The energy loss ration due to hysteresis does not strongly depend on strain rate. In collision of the ball with the stress bar, only 65% to 45% of the initial kinetic energy is converted to the rebound kinetic energy. This ratio decreases with increase of the impact velocity. Among the rest of the energy, 25% to 40% is dissipated by internal friction, about 10% is transmitted as elastic wave energy to the stress bar and the rest several % remains in the ball as strain energy and vibration energy.