Analyse basse frequence des chocs pyrotechniques Pyrotechnic shocks – low frequency analysis

Separation of launcher stages generates pyrotechnic shocks which lead to high acceleration levels on equipments. This paper describes a method used by EADS Launch Vehicles to estimate the low frequency response of these equipments. This method is used on Ariane 5 or military launchers to decide whether it is necessary to set dampers between the main structure and an equipment. A time excitation is first built in order to represent the low frequency part of the pyrotechnic shock (less than 1 000 Hz). This time history is then used as an input to compute the dynamic response of the structure. In the industrial example shown at the end of the paper, the use of a damping device is necessary in order to reduce the acceleration level on an equipment. The theoretical and practical limits of this method are presented as a conclusion.