A combined VPT and SVT approach for decoupling in the presence of inaccessible and deformable interfaces

Substructure decoupling identifies a subsystem within a mechanical system by removing the measured dynamics of other subsystems from that of the assembly. Challenges persist in this procedure in the presence of inaccessible and flexible interfaces, measurement errors and noise. Various approaches address these issues: the Virtual Point Transformation (VPT) reduces noise at boundary DoFs but fails to capture the interface flexibility. The extended decoupling interface can help to overcome this limitation by involving internal DoFs in the decoupling but leads to major error propagation. The Singular Vector Transformation (SVT) reduces errors at internal DoFs but lacks a physical description of the interface. This work proposes different approaches to decoupling that combine VPT, the extended interface, and SVT to retain the interface flexibility and to smooth measurement errors at all DoFs while describing the interface topology with physical coordinates. Advantages are demonstrated on a laboratory benchmark structure using experimental data.