Multiaxial Damage Characterization of Carbon/Epoxy Angle-Ply Laminates under Static Tension by Combining In Situ Microscopy with Acoustic Emission

Abstract

Investigating the damage progression in carbon/epoxy composites is still a challenging task, even after years of analysis and study. Especially when multiaxial stress states occur, the development of damage is a stochastic phenomenon. In the current work, a combined nondestructive methodology is proposed in order to investigate the damage from the static tensile loading of carbon fiber reinforced epoxy composites. Flat angle-ply laminates are used to examine the influence of multiaxial stress states on the mechanical performance. In situ microscopy is combined with acoustic emission in order to qualitatively and quantitatively estimate the damage sequence in the laminates. At the same time, digital image correlation is used as a supporting tool for strain measurements and damage indications. Significant conclusions are drawn, highlighting the dominant influence of shear loading, leading to the deduction that the development of accurate damage criteria is of paramount importance. The data presented in the current manuscript is used during ongoing research as input for the damage characterization of the same material under fatigue loads.

Keywords

• carbon fiber reinforced epoxy composites
• nondestructive techniques
• microscopy
• acoustic emission
• damage investigation
• multiaxiality