PHYSICAL MODELING OF THE COUPLING OF VIBRATING STRUCTURES IN MUSICAL-INSTRUMENTS WITH COMPLEX STRUCTURE

In an instrument such as the piano, the coupling phenomena between the vibrating structures (the strings) play an important part. Firstly when there are two or three strings for each note, the coupling between these strings produces an ''aftersound'' phenomenon. Secondly, the vibration of the bridge causes the vibration of the other free strings. In this work, the coupling phenomena are physically modelled and simulated. The design tool is the CORDIS-ANIMA system developped by the ACROE laboratory. CORDIS-ANIMA is a digital instrument simulator based on the principle of concentrated masses (a discrete network of masses springs and dampers). At first was elaborated a model of two coupled strings as close as possible to the coupled strings in the piano. Afterwards this model was generalized to N strings. This new model produced aftersound as for the previous model ; but in addition it also accounted for the vibration transmission to harmonic strings. Finally, other structures than StringS Were also modelled on this coupling structure.