On the use of the coupled velocity for the estimation of transmitted mechanical power

Sound power of a source is traditionally considered to be an adequate quantity for acoustical source characterization. For a vibrational power source such simple characterization does not exist due to the more complex nature of structural vibrations. This type of source is usually studied using measurements, although numerical simulations are more suitable for this task. Basic theory for power transmission through point connections exists and is well documented. In this paper the attachment of a complicated source and a simple, easy to model receiver is studied. It is assumed that the real joint behavior can be described using one or a number of points. The basic idea is to define the power transmission using measured translational coupled velocities of the whole structure and a validated model of the receiver. Method development is done using finite element simulations. The principle is validated with a flange stiffened plate source attached by beams to a flat plate receiver. The effect of the number of measurement points, inaccuracies in measurements and imperfection of real structures among other things are studied. The presented method is accurate because it uses an exact receiver mobility matrix. The procedure is generally applicable for solid structures.