Tension helical springs are used in doors as a mechanical energy storage solution, and at the same time they represent a critical element for performing the basic function of a door. In each cycle of door opening, the springs are subjected to a pulse in the longitudinal direction, which triggers its own dynamic response, which in turn affects their lifespan. In order to determine the impact of dynamics on the spring fatigue life, dedicated testing device for accelerated testing of tension springs was created. The eigenfrequencies of the selected spring were determined using the impedance method and string theory. These methods prove to be suitable for determining the natural frequencies of the selected spring, since the experiment confirmed the values of theoretically and numerically determined natural frequencies. Based on experimental tests, it was found that the excitation of a spring at its own frequency has a great influence on its lifespan.
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