Investigation of Tensile Property of Thin Ply Composite Laminate with Open-Hole Assisted by Acoustic Emission Technology

Abstract

As the application of carbon fiber reinforced polymer composite (CFRP) laminates in aerospace and aircraft structures, opening hole is inevitable in design, fabricate and assemblage. However, the open-hole procedure has a bad effect on mechanical properties of the composite laminate. In this paper, characters of acoustic emission (AE) and curve of stress-strain of composite laminate with open-hole under tensile test were obtained. It was found that onset damage stress of a thin ply laminate detected using acoustic emission was higher than that of the standard ply laminate with the decreasing of ply thickness, while ultimate open-hole tensile strength of the thin ply laminate was lower than that of the standard ply laminate. More homogeneous microstructure and balanced stacking sequence make the thin ply laminate have higher initial damage stress. AE signals of matrix damage and delamination are presumably classified by the amplitude, which validate superior damage suppression and delamination resistance in the thin ply laminates. Stress concentration around the open-hole cannot be relaxed under tensile test as higher damage suppression and delamination resistance in the thin ply laminate. That can lead the thin ply laminate has lower open-hole tensile strength.