Vibration attenuation of conical shell and stepped beam structure based on magnet-spring nonlinear energy sink (MS-NES)
摘要
Conical shells are widely used in engineering for their ease of manufacture and high load-bearing capacity, their flexibility often induces vibrations that affect the precision of instruments installed inside. This paper proposes a magnet-spring nonlinear energy sink (MS-NES) designed for broadband, low-frequency vibration reduction of the conical shell and stepped beam structure. Combining two pairs of vertically repulsive permanent magnets with two lateral springs creates a double potential well and a smooth negative stiffness segment. The MS-NES leverages internal resonance characteristics to rapidly capture and dissipate vibrational energy of the main structure, thereby achieving vibration reduction. The proposed MS-NES structure reduces the root mean square vibration displacement response at four measurement points of the conical shell and stepped beam structure by 2.36 dB within the 10–100 Hz frequency range, achieving a 71% improvement compared to the traditional tuned mass damper. Furthermore, through nonlinear dynamic analysis, it is pointed out that the internal resonance of MS-NES reduces the peak vibration response at the structure's natural frequency. In the end, the parametric study shows that the vibration reduction effect of the MS-NES weakens first and then strengthens as the mass increases, while increasing MS-NES damping can enhance broadband vibration reduction performance.