Effects of internal resonances in the pitch glide of Chinese gongs

Marguerite Jossic (1, 2) , Olivier Thomas (3) , Vivien Denis (3) , Baptiste Chomette (2) , Adrien Mamou-Mani (1) , David Roze (1)

1 S3AM - Systèmes et Signaux Sonores : Audio/Acoustique, instruMents
2 DALEMBERT - Institut Jean Le Rond d'Alembert
3 LISPEN - Laboratoire d’Ingénierie des Systèmes Physiques et Numériques

The framework of nonlinear normal modes gives a remarkable insight into the dynamics of nonlin-ear vibratory systems exhibiting distributed nonlinearities. In the case of Chinese opera gongs, geo-metrical nonlinearities lead to a pitch glide of several vibration modes in playing situation. This study investigates the relationship between the nonlinear normal modes formalism and the ascendant pitch glide of the fundamental mode of a xiaoluo gong. In particular, the limits of a single non- linear mode modeling for describing the pitch glide in playing situation are examined. For this purpose, the amplitude- frequency relationship (backbone curve) and the frequency-time dependency (pitch glide) of the fundamental nonlinear mode is measured with two excitation types, in free vibration regime: first, only the fundamental nonlinear mode is excited by an experimental appropriation method resorting to a phase-locked loop; second, all the nonlinear modes of the instrument are excited with a mallet impact (playing situation). The results show that a single non-linear mode modeling fails at describing the pitch glide of the instrument when played because of the presence of 1:2 internal resonances implying the nonlinear fundamental mode and other nonlinear modes. Simulations of two nonlinear modes in 1:2 internal resonance confirm qualitatively the experimental results.

Domaines: Acoustique [physics.class-ph]; Vibrations [physics.class-ph]; Mécanique des solides [physics.class-ph]

Marguerite Jossic, Olivier Thomas, Vivien Denis, Baptiste Chomette, Adrien Mamou-Mani, et al.. Effects of internal resonances in the pitch glide of Chinese gongs. Journal of the Acoustical Society of America, 2018, 144 (1), pp.431-442. ⟨10.1121/1.5038114⟩. ⟨hal-01862794⟩