Abstract

Experimental and hybrid substructuring allow the virtual analysis of complex structures that are rather represented by experimental models than simulations. Coupling the experimental models with other structures requires adequate driving points generally described by six degrees of freedom with three translations and rotations with forces and torques as inputs as well as translational and angular accelerations as outputs.

However, the measurement of these driving points is challenging. In particular, experimentally acquiring all six inputs causes the main effort. For example, excitation devices that directly exert a torque are not widely applicable or three translational directions are not accessible.

Therefore, adapter structures are frequently used in practice, which increase the experimental effort or can be impractical due to a lack of space and reachability.

The proposed strategy is the replacement of active excitation devices, i.e. impulse hammers or shakers, on the driving points, by passive, rigid bodies, simply referred to as masses.

Compared to the existing mass uncoupling method which is also based on this fundamental idea, the main improvement is a simplified notation that enables the incorporation of data from multiple masses and parametric state-space systems. The main finding is that the proposed strategy is suited to estimate driving point dynamics that allow to predict the effect of assembled structures on channels that were not used in the estimation of the driving point, indicating the physical relevance of the estimated dynamics.

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