This test unit enables various equivalent stress hypotheses from materials science to be checked experimentally. Specimens made of different metals can be placed in a state of stress in several axes. A circular shaped load plate is used as a lever for the load moment, loading is applied by attaching weights to the circumference of the plate. The specimen is clamped in the center of the plate using clamping levers. Via the defined points for the application of force, combined bending and torsion loading is generated. The angular position of the load weight can be moved in 10o steps. The deformation is measured diametrically opposite the points where the force is applied, that is at the point of maximum deflection. In this way the measurement error due to the deformation under load of the test apparatus is minimized. Compensation for the dead weight of the plate and compensation for the load weight ensure specimen loading is free of transverse forces.