Three dimensional measurement of the dynamical behaviour of mechanical components with laser vibrometers

A measurement system is described that detects the Doppler-shift of light scattered by an object surface to determine the time dependence of the velocity vector at several discrete points on the object.The scattered light is received from three noncoplanar viewing directions to get information about the complete velocity vector. From the measured data the dynamic behaviour of the object is derived under certain excitation conditions. In contrast to conventional methods the measurement is performed contactless without any additional mass-load to the structure. This is a decisive advantage for measurements of surface movements of components with light dynamical mass.