Complete automatic performance of experiments to determine fatigue crack growth.

For the prediction of lifetimes of cyclic loaded structural components; the knowledge of the crack propagation behaviour is very important. But the determination of corresponding data requires a great effort. In this contribution a test equipment is presented which allows fully automated crack propagation experiments in different test modes on specimens with a simple geometry. On the example of a particle-reinforced and an unreinforced aluminium alloy it will be shown that only two experiments are necessary to predict all crack propagation curves for stress ratios between -1 < R < 0,85. With the help of stress-strain and potential drop hysteresis loops the crack closure behaviour can be investigated.