Patent ID: 8621934
Filing Date: 2014-01-07
Classification: F03D,F05B,G01M,Y02E

Abstract:
1. An apparatus for fatigue testing elongate test articles, comprising: a test stand at least semi-rigidly retaining an end of an elongate test article; an actuator assembly attached to the test article, wherein the assembly is not attached to a ground plane, and adapted for imparting a first external load in a first direction on the test article and a second external load in a second direction on the test article, the first and second directions of the external loads being transverse to a longitudinal axis of the test article and transverse to each other; and a controller transmitting a first set of displacement signals to the actuator assembly at a first resonant frequency of the test article and a second set of displacement signals to the actuator assembly at a second resonant frequency of the test article, wherein the first resonant frequency is about a resonant frequency of the wind turbine blade test system in a flapwise direction of the wind turbine blade and the second resonant frequency is about a resonant frequency of the wind turbine blade test system in an edgewise direction, the first and second sets of displacement signals initiating the first and second external loads applied by the actuator assembly to concurrently oscillate the test article in first and second directions, respectively, wherein the first set of displacement signals includes a first amplitude and wherein the second set of displacement signals includes a second amplitude differing from the first amplitude.