Nonlinear oscillations of a current-carrying string in a magnetic field
Александр Константинович Томилин, Коноваленко Иван Сергеевич, Igor S. Konovalenko · Vestnik Tomskogo gosudarstvennogo universiteta Matematika i mekhanika · 2024
The nonlinear properties of a string must be taken into account when creating string systems that are used in transducers and musical instruments. The forced oscillations of an electrically conductive string in a magnetic field are described by a nonlinear integro-differential equation. The amplitude-frequency characteristics of nonlinear resonances of the first and second orders are obtained. The damping factor of the first-mode oscillations is determined from the optimal coincidence of the experimental and theoretical amplitude-frequency characteristic graphs. The experimental amplitude-frequency characteristics for the first-order resonance is obtained using a laboratory setup with a copper string 0.4 mm in diameter and 0.57 m long, having a certain initial tension. The cumulative damping factor of the first mode is obtained, which takes into account all the dissipative factors of a real string system. Low-frequency thermoparametric oscillations of the second mode are observed in experiments with a string. It follows from the analysis of the Mathieu equation that parametric resonance arises even at very low amplitudes of the thermal tension of a string, and it must be taken into account in the frequency analysis of oscillations of string systems. The authors are grateful to Tomilin V.A. for his help in performing the calculations and graphic work. The authors declare that they have no conflict of interests.