SIMULATION USING COMPUTER-PILOTED POINT EXCITATIONS OF VIBRATIONS INDUCED ON A STRUCTURE BY AN ACOUSTIC ENVIRONMENT.

It is now possible to compute the overall levels and spectral densities of the responses measured on a launcher skin (the fairing for instance) and merged into a random acoustic environment during takeoff. However, the analysis of the transmission of these vibrations to the payload requires the simulation of these responses by means of a shaker-control system using a small number of distributed shakers. This closed-loop computer-based digital system allows the acquisition of auto and cross spectral densities and equal to those of the responses previously computed. Its possibilities are large (for instance, road and runway profiles). The problems to be solved are: multiple input-output system identification, multiple true random signal generation, and real-time programming; a system under development should allow the control of four shakers.