Local Strain and Damage Measurements on a Composite with Digital Image Correlation and Acoustic Emission

TLDR: In this article, the authors combine Digital Image Correlation (DIC) and Acoustic Emission (AE) measurements to correlate strain measurements and damage location on a complex composite material during a monotonic tensile test.

Abstract: Certain material have a non linear stress-strain behaviour under monotonic loading. This non linearity can be caused by continuous damage. To highlight this phenomena simultaneous strain and damage measurements should be taken. When working with inhomogeneous or anisotropic materials, such as continuous fibre composites, local information is essential. On the one hand, full field strain data can be obtained with Digital Image Correlation (DIC). On the other hand Acoustic Emission (AE) recording is a method that can be used for damage monitoring and location if, at least two sensors are placed on the specimen under loading. The aim of this work is to combine these two techniques to correlate strain measurements and damage location on a complex composite material during a monotonic tensile test. This composite is a continuous fibre reinforced friction material used in car clutches. These measures were used to understand the non linearity of the stress-strain curve of the as received material as well as detect volume damage after thermal cycling.