Experimental and numerical study on failure mechanisms of tapered laminates: Effects of thickness and ratio

Although the variable ply drop-off strategy in tapered laminates offers design flexibility for composite components, it introduces significant challenges to structural reliability due to the discontinuity and stress concentration caused by ply termination. In light of this, we present an integrated experimental and numerical investigation into the failure mechanisms of tapered composite laminates. Interrupted tensile tests are employed to analyze the progressive damage processes of these laminates, considering the effects of taper ratio and ply thickness. Comprehensive failure examinations are conducted alternately using optical microscopy, Xray radiography, and X-ray computed tomography. In parallel, a generic failure model is developed within the framework of finite element method. It enables the prediction of failure loads and damage patterns in the laminate specimens, allowing for comparison with test results. A strong correlation between numerical modeling and experimental reference has been achieved, which clarifies the interdependence of failure behavior on ply thickness and taper ratio. For identical structural compositions, it is demonstrated that the utilization of thin plies and shallow tapers enhances the damage resistance of laminate structures with ply drop-offs.