PHYSICAL MODELING OF THE COUPLING OF VIBR ATING 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 wh en there are two or three strings for each note, the coupling between these strings produces an ''aftersound'' phenomenon. Secondly, the vib ration of the bridge causes the vibration of the other free strings. I n this work, the coupling phenomena are physically modelled and simula ted. The design tool is the CORDIS-ANIMA system developped by the ACRO E laboratory. CORDIS-ANIMA is a digital instrument simulator based on the principle of concentrated masses (a discrete network of masses spr ings and dampers). At first was elaborated a model of two coupled stri ngs as close as possible to the coupled strings in the piano. Afterwar ds this model was generalized to N strings. This new model produced af tersound as for the previous model ; but in addition it also accounted for the vibration transmission to harmonic strings. Finally, other st ructures than StringS Were also modelled on this coupling structure.