QUANTITATIVE ACOUSTIC-EMISSION FOR FRACTURE-BEHAVIOR OF CENTER-HOLE GFRP LAMINATES

Residual strength prediction through acoustic emission (AE) detection and analysis is attempted for tensile loading of GFR composite laminates containing center holes. By utilizing a previously developed two-parameter fracture mechanics model, the mechanical behavior of circular center hole composite specimens was interpreted. The AE response of the specimens was shown to be controlled by stress intensity factor K1 rather than stress. In order to establish a quantitative basis for AE analysis aimed at predicting the fracture behavior of center hole composite laminates, a description of the experimental AE response through a mathematical model was considered necessary. An analytical expression of exponential form was assumed and experimentally verified. The excellent agreement between theory and experiment quantitatively confirmed the validity of the model. Through AE detection and analysis, it is therefore possible to assess hole criticality in composite laminates by direct prediction of their residual strength under tensile loading.