Abstract
The study of fatigue strength of material is practical importance, but a testing time is very long and a cost of ordinary testing machine is very high Then the many arrangements of testing machines are practically difficult. In order to exclude these difficulties, the very simple apparatus is designed here, for instance, such as the elastic part (the test piece) and the inertia block with electrical magnets are joined together and the nodes of inertia block in the natural vibration are suspended by two fine wires. This apparatus vibrates in the natural frequency of the resonant state making use of the electrical contacts. Then the consumption of electrical energy is very few. Also the study of dynamical properties of the elasticity and the internal friction of the test piece can carry out.
