Study on the dynamic characteristic of a contact surface (The logarithmic decrement and natural frequency dependent on an amplitude of vibration)

When an impulse force is given to a fixed element, the logarithmic decrement and the natural frequency of the fixed element depend on the amplitude of vibration. From the logarithmic decrement and the natural frequency obtained from this method, stiffness and energy loss of the fixed element are calculated. The stiffness and energy loss are compared with those obtained statically. Static stiffness and energy loss of the fixed element are obtained from the hysteresis loop which occurs when applying an oscillating tangential load statically to the fixed element. It is consequently found that the relation of stiffness or energy loss obtained dynamically versus the amplitude of the oscillating tangential load is qualitatively in good agreement with that obtained statically.