# A combined experimental/numerical study on the scaling of impact strength and toughness in composite laminates for ballistic applications

**Authors:** Stefano Signetti, Federico Bosia, Seunghwa Ryu, Nicola M. Pugno  
**arXiv:** [2109.12312](https://arxiv.org/abs/2109.12312)  
**Date:** 2021-09-25  
**Summary page:** https://www.summarizepaper.com/en/paper/2109.12312v2/

## Key points

- Authors investigate impact behavior of composite laminates for ballistic protection
- Study focuses on three representative fiber-reinforced epoxy systems: carbon, glass, and para-aramid
- Multiscale coupled experimental/numerical approach used to analyze composite material properties
- Uniaxial tensile tests conducted on single fibers and fiber bundles for input data
- Non-linear Finite Element Method (FEM) models simulate tensile and impact scenarios on composite laminates
- FEM simulations used to assess ballistic impact performance of multilayer armors using different composites
- Results show good agreement with experimental tests in terms of energy absorption and deformation/failure behavior
- Generalized multiscale version of Cuniff criterion provided as a scaling law for predicting laminate properties based on individual constituents' properties at single fiber scale

## Summary

In this paper titled "A combined experimental/numerical study on the scaling of impact strength and toughness in composite laminates for ballistic applications," authors Stefano Signetti, Federico Bosia, Seunghwa Ryu, and Nicola M. Pugno investigate the impact behavior of composite laminates and assess their potential for ballistic protection. The study focuses on three representative fiber-reinforced epoxy systems involving carbon, glass, or para-aramid fiber reinforcements. The research employs a multiscale coupled experimental/numerical approach to analyze the composite material properties at various levels. It begins with single fibers and progresses to fiber bundles (yarns), single composite plies, and finally laminate structures. Uniaxial tensile tests are conducted on both single fibers and fiber bundles to obtain input data for non-linear Finite Element Method (FEM) models. These models simulate tensile and impact scenarios on the composite laminates in order to evaluate their mechanical properties and energy dissipation under quasi-static loading. The FEM simulations are further used to assess the ballistic impact performance of multilayer armors using the three different composites (carbon, glass, or para-aramid). The results show good agreement with experimental tests in terms of impact energy absorption capabilities and deformation/failure behavior. As a result of their analysis, the authors provide a generalized multiscale version of the well-known Cuniff criterion as a scaling law that allows for predicting full-scale laminate properties based on the individual constituents' properties at the single fiber scale. Overall, this study presents a comprehensive investigation into the impact behavior of composite laminates for potential use in ballistic protection applications.