Abstract

Environmental tests for Vibration Endurance specify testing at constant acceleration or constant displacement amplitude over certain frequency ranges, Cycling over an appreciable frequency range must provide compensation for impedance changes at the input of an electro-dynamic type shaker. These impedance changes are diagrammed and discussed, and the influence of the mechanical load examined. The desirability of such an arbitrary specification is examined in the light of possibly unforeseen effects on the object under test.