# Mesoscale Model for Composite Laminates: Verification and Validation on Scaled Un-Notched Laminates

## TL;DR

This paper introduces and validates a mesoscale model for predicting damage in carbon-fiber reinforced polymer laminates under different loading conditions.

## Contribution

A revised longitudinal damage law and a 3D frictional smeared crack model are combined for predicting failure mechanisms in composite laminates.

## Key findings

- The model successfully predicted intralaminar damage and delamination in un-notched CFRP coupons.
- Validation showed good agreement with experimental data for both tensile and compressive loading.
- The model captured scaling effects at sublaminate and ply levels.

## Abstract

This paper presents a mesoscale damage model for composite materials and its validation at the coupon level by predicting scaling effects in un-notched carbon-fiber reinforced polymer (CFRP) laminates. The proposed material model presents a revised longitudinal damage law that accounts for the effect of complex 3D stress states in the prediction of onset and broadening of longitudinal compressive failure mechanisms. To predict transverse failure mechanisms of unidirectional CFRPs, this model was then combined with a 3D frictional smeared crack model. The complete mesoscale damage model was implemented in ABAQUS®/Explicit. Intralaminar damage onset and propagation were predicted using solid elements, and in-situ properties were included using different material cards according to the position and effective thickness of the plies. Delamination was captured using cohesive elements. To validate the implemented damage model, the analysis of size effects in quasi-isotropic un-notched coupons under tensile and compressive loading was compared with the test data available in the literature. Two types of scaling were addressed: sublaminate-level scaling, obtained by the repetition of the sublaminate stacking sequence, and ply-level scaling, realized by changing the effective thickness of each ply block. Validation was successfully completed as the obtained results were in agreement with the experimental findings, having an acceptable deviation from the mean experimental values.