On the experimental linear identification of a multiple-joint bolted connection using frequency-based substructuring

The dynamics of bolted joints are still an essential uncertainty in the modeling of machines. Frequency-based substructuring techniques have been successfully applied to isolate the linearized dynamics of one bolted joint in six degrees of freedom. A step towards the identification of flange connections is to apply the isolation for an assembly with multiple joints. In this contribution, an assembly connected via two bolted joints is investigated, where the dynamics of both bolted joints are isolated in a single decoupling step. Due to the stiff bolted joint connection, the substructuring problem is ill-conditioned. Strategies to deal with the ill-conditioning are presented. The performance is assessed by reconstructing the assembly dynamics with the identified joint and comparing them to the measured FRFs.