Evaluation of interlaminar shear of laminate by 3D digital holography

- The technique of three-color digital holography is applied on composite material.
- Flax/epoxy and flax/carbon/epoxy are submitted to a short beam shear test.
- Three-color digital holography provides access to a three-dimensional displacement measurement.
- This first crack is not necessarily visible on the strain/stress curves.
- Interlaminar shear is detected in the phase, displacement and deformation fields.
- The SBS test coupled with holography can compare the rigidity of both composite.

In this paper, we propose a three-color holographic interferometer devoted to the 3D displacement field analysis of a composite material. The method in applied to analyze cracks during a short beam shear test. The tested materials are a glass/epoxy composite, a flax/carbon/epoxy composite and a flax/epoxy composite. Such an evaluation provides a pertinent parameter to detect premature cracks in the structure, long before it becomes visible on the real time stress/strain curve, or with a classical microscope. Moreover, the mechanical proprieties of flax/carbon/epoxy composite and flax/epoxy composite are compared.