Experimental study on interaction between matrix crack and fiber bundles using optical caustic method

•Caustic parameter equation at crack tip near the fiber bundle is established.•Material properties of fiber bundle on the caustics are analyzed theoretically.•Caustic experiment for the interaction between crack and fiber bundle is finished.

The stress singularity of the matrix crack perpendicular to the fiber bundles was studied by the method of optical caustics. First, the strain fields at the matrix crack tip in the neighbor of the fiber bundles were derived based on transformation toughening theory and Eshelby inclusion method. Then the caustic equation at the matrix crack tip in the neighbor of the fiber bundles was established. Finally, an optical caustic experiment for the interaction between the matrix crack and the fiber bundles was conducted to visualize the stress singularity at the matrix crack tip in the form of caustic spots.

Graphical abstractCaustic spots for different distances from the crack tip to the fiber bundles.Figure optionsDownload full-size imageDownload as PowerPoint slide