In H-shaped specimens the individual joints are subjected to common cyclic loading in tension and compression and the fasteners to a shear effect. H-specimen grips designed for this test initially distribute the forces over the entire structure. The bending-up and resultant loosening of the structure can be measured with an extensometer. With the strain values the testing machine –
in this case also a Vibrophore – can provide control of loads or strain, depending on how the test is conducted.