Relation between ASTM E606 specimen geometry and misalignment in strain-controlled fatigue testing

•Inhomogeneous strain distribution under compression was captured from the very first cycle in strain-controlled fatigue testing by stereo-DIC.•A novel fixture is designed to monitor the misalignment of the specimens in uniaxial fatigue testing.•Numerical simulation has reproduced this non-uniform strain distribution under compression to further validate the stereo-DIC measurements.