In-situ damage assessment of FML joints under uniaxial tension combining with acoustic emission and DIC: Geometric influence on damage formation

This work presents an in-situ assessment of damage occurring in the single-lap fiber metal laminate joints with various geometries under uniaxial tension and identify the crucial geometric role in the damage formation. The acoustic emission combined with digital image correlation is applied to record the damage events and strain field. The identification is made with the peak frequency, in which intervals of peak frequency containing [0-100 kHz], [100-200 kHz], [200-300 kHz] and [300-400 kHz] represent matrix/metal crack, delamination, fiber pull-out and breakage, respectively. The Hashin criterion, cohesive constitutive relation and ductile damage criterion are used to predict the damage evolution of fiber metal laminate. The combination of cumulative AE energy and simulation results reveals damage onset, evolution and severity. The incongruity of bearing capacities and stress situations caused by the distinction of geometric parameters result in the bearing damage, the brittle damage and the ductile shear damage in different structures.

Automated summary

The study assesses the damage in single-lap fiber metal laminate joints with various geometries under uniaxial tension, using acoustic emission and digital image correlation to record events and strain fields, with identification based on peak frequencies corresponding to different types of damage. The analysis utilizes Hashin criterion, cohesive constitutive relations, and ductile damage criterion to predict damage evolution in fiber metal laminate.