Abstract: The invention relates to a mechanical testing device with at least one load frame , and , which has a frame part and a clamping device held therein, in which a beam-shaped test specimen, in particular a rotor blade or rotor blade segment, can be clamped projecting through the load frame, the load frame being mounted in a first pivot bearing arrangement on a carrier frame or a support frame so as to be rotatable about a first transverse axis of the test specimen which extends perpendicularly to its longitudinal axis projecting through the clamping device, wherein the frame part has a four-fold rotational symmetry, in particular a square shape, or an annular shape. The design of the load frame(s) results in easy rotatability/adjustability of the test specimen. In a method for carrying out the test, the system natural frequencies in different loading directions can be suitably matched.