NOVELTY - The test specimen (1000) has an inner core (100) incorporated into outer fiber-reinforced plastic composite (200). The inner core is widened in a transverse axis in relation to the applied mechanical load in such a way that the composite with the inner core has a greater buckling stability than the composite without the inner core. The inner core is formed in such a way that an influence on the to-be-determined specific material property of the fiber-reinforced plastic composite lies in an acceptance range.    USE - Test specimen for determining specific material property of fiber-reinforced plastic composite of rotor blade of wind energy plant (all claimed).    ADVANTAGE - The mechanical loads or specific material properties of fiber-reinforced plastic composite can be determined accurately, while reducing the measurement errors. The test specimen can be intended to give necessary stability to the rotor blade to reproduce or replicate actual load effects and loading states. The cracks or the propagation of cracks under dynamic loading and the occurrence of material fatigue can be traced more easily. The inner core can restrict the sensitive bending behavior of fiber-reinforced plastic composites and that the measured tensile and compressive strengths correspond to the axial alignments of the fiber composite and can optimize the testing procedure correspondingly. The introduction of force in the test specimen can take place by way of the axial alignment, without requiring the previously demanded high axial alignment. The test specimen can allow a usable testing procedure that can reflect the failure of the component without having the faults to be expected of a test method. The test specimen can allow dynamic loads to be applied without measuring errors or premature failures that have an adverse influence on the assessment of the fiber-reinforced plastic composite being represented by buckling failure.    DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for method for testing test specimen.    DESCRIPTION OF DRAWING(S) - The drawings show perspective view of the specimen, and schematic views of the test specimen and testing apparatus for testing test specimen.    Inner core (100)    Outer fiber-reinforced plastic composite (200)    Strain gauge (300)    Test specimen (1000)    Testing apparatus (2000)