A Study on the Intralaminar Damage and Interlaminar Delamination of Carbon Fiber Composite Laminates Under Three-Point Bending Using Acoustic Emission

The complicated failure mechanisms are always distinct features of composite materials which largely affect the stiffness and strength as well as the structural integrity. Yet, until now there are still no mature methods based on various test approaches for accurately predicting the failure mechanisms and damage evolution behaviors of composite structures by considering the effects of loads, environments, and material defects. This research designs and prepares the [0°16//0°16], [30°16//30°16], and [15°/−15°]3s//[15°/−15°]3s carbon fiber composite specimens with initial interlaminar cracks, and performs the single-leg and over-leg three-point bending mechanical experiments and acoustic emission (AE) tests of composite specimens under 70 °C temperature. The effects of the layup patterns, the loading conditions, and the initial interlaminar crack length on the intralaminar damage and interlaminar delamination behaviors of composite laminates are comparatively studied by analyzing the response process of the AE characteristic parameters including the amplitude, energy, and counting. The AE analysis provides theoretical and technique support for further elucidating the complicated failure mechanisms and their interactions of carbon fiber composite laminates. © 2014, ASM International.