IMPROVING INTERFACE CONDITIONS IN MODAL SYNTHESIS METHODS. APPLICATION TO A BOLTED ASSEMBLY OF RECTANGULAR PLATES

摘要

Vibration analysis of complex structures which comprise an assembly of components with special connections (bolted joints etc..) can be carried out using a free interface substructuring method. Good computed results are generally obtained when the interface forces (shearing forces, bending moments etc..) are well represented. For a system of two rectangular plates, we prove that introduction of rotational degrees of freedom (RDOF) at connection nodes associated with simplified and adapted joint models improve the accuracy for the modes of the assembly. An original approach to determining rotational data from translational measurements is developed. This approach is validated considering the free vibrations of a simple rectangular plate. Sources of errors influencing rotational degrees of freedom estimations are presented such as the weights of accelerometers, the experimental meshing density. Introduction of the estimated experimental rotational degrees of freedom in component dynamic properties and correspondant component modal synthesis (CMS) solutions show better results for the lower modes of the entire structure than considering only translational data.