Rigid body and nonlinear mount identification: Application to onboard equipment with hysteretic suspension

This article describes a step-by-step procedure for improving the dynamic behavior of a rigid body mounted on a linear flexible structure with nonlinear hysteretic suspension. Special attention is paid to the inertia property identification carried out with an original experimental technique. The hysteretic suspension parameters are measured with a specific device. Condensation anti modal methods permit reducing the number of equations of the finite element model of the structure with localized nonlinearities. The technique (numerical and experimental) is applied to an onboard camera that, under real operating conditions, is carried externally on a helicopter. As the model is validated by experiments, the simulated modification, which better reduces the vibration level of the camera, is retained. The new assembly has been designed and successfully tested.