The present paper investigates crack growth in specially designed specimens of 6061 aluminium alloy sheets subjected to dynamic shear loads. The specimens were tested with a low-frequency alternating shear load until complete fracture. The main objective of this work was to observe the crack initiation and growth under alternating shear load using the Digital Image Correlation (DIC) method. Each time the peak amplitude was reached, a photograph of the shear area on the specimen surface was taken to investigate crack grow. The length of the crack in every load cycle was then estimated by an algorithm using the DIC strain fields as input data. The DIC results were compared to FE. The observation of the shear strain component is presented as the most appropriate method to predict the location of the crack even before its initiation.