Coil springs are used in high-speed doors as a mechanical energy accumulator, which contributes to a rapid opening of the door leaf. Due to the rapid opening and jerky movements, the springs oscillate, which can reduce their service life. Using the dynamic stiffness formulation, the natural frequencies of the considered spring were determined. This was followed by the identification of critically loaded points based on implicit and harmonic analysis. With a modified Goodman diagram and Bergmann correction, service life of critical points on the spring was estimated. The results were experimentally verified. It has been found that the response with natural frequency modes leads to higher stresses and shorter service life, if compared to the quasi-static case.
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