AE parameter-based characterization of hybrid materials¶ fracture

The present paper describes fracture monitoring cases in construction materials, where the basic role is played by acoustic emission (AE). It is shown that certain waveform parameters exhibit strong sensitivity to the rate of fracture development as well as the dominant fracture mode. The focus is given on the family of textile-reinforced cement and hybrid structures, which recently gain a lot of ground in engineering as repair patches or structural elements. Due to laminated and fibrous nature, their fracture behavior is more complicated
than other conventional materials and therefore, AE can provide valuable and innovative information on the topic. Parameters like frequency content and the duration of the signals supply real time trends that in the present cases
are verified by optical techniques. It is concluded that AE offers valuable insight and allows the prediction of how the material will behave based on the initial AE recordings and before serious damage is inflicted. Furthermore, correlations of the AE parameters with strain prove also strong allowing AE to distinguish between normal and shear strain field well before the observation of the eventual cracking. Although AE exhibits great application range, the contribution of other monitoring techniques is highlighted in order to increase the reliability of the
interpretation of AE results.