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 laminat es containing center holes. By utilizing a previously developed two-pa rameter fracture mechanics model, the mechanical behavior of circular center hole composite specimens was interpreted. The AE response of th e specimens was shown to be controlled by stress intensity factor K1 r ather than stress. In order to establish a quantitative basis for AE a nalysis aimed at predicting the fracture behavior of center hole compo site laminates, a description of the experimental AE response through a mathematical model was considered necessary. An analytical expressio n of exponential form was assumed and experimentally verified. The exc ellent agreement between theory and experiment quantitatively confirme d the validity of the model. Through AE detection and analysis, it is therefore possible to assess hole criticality in composite laminates b y direct prediction of their residual strength under tensile loading.