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Several available mathematical models for vibration dampers were compared to dynamic test results. The comparison results in a simple model that agrees well with both the magnitude and phase characteristics of experimentally obtained frequency response functions. The resulting model can be used as a correct boundary condition for finite element models of the structure to which the dampers are attached.

A distributed sensor is created to sense the rate of change in deflection of beam-like structures such as crane booms. This sensor will be useful in electrohydraulic compensation of boom deflections. The sensor is made of an array of strain-sensitive segments such as strain gages or piezoelectric film. In this example, segments of piezoelectric film convert strains on the surface of a vibrating beam into electrical outputs. These outputs are connected to low impedance signal conditioners. The output of the signal conditioners are then interpolated with a weighting vector that incorporates Lagrange polynomials, specified boundary conditions, and the desired location(s) of measurement. A simple linear combiner circuit combines the electrical outputs into the deflection velocity at the desired points.