# Failure Mechanism of Pre-Stressed CFRP Beam Under Laser Ablation

## TL;DR

This study examines how pre-stressed carbon fiber beams fail when exposed to laser ablation, finding that compression failure at the bottom surface occurs due to heat softening.

## Contribution

The study identifies the failure mechanism of pre-stressed CFRP beams under laser ablation, emphasizing the role of heat-induced compression failure.

## Key findings

- CFRP beam failure occurs in compression at the bottom surface due to heat softening, not top surface ablation damage.
- Failure time decreases with increasing laser power density and pre-stress loading.
- Pre-stress loading has a greater impact on failure time than laser power density.

## Abstract

This paper focuses on the failure mechanism of a pre-stressed CFRP cantilever beam under laser ablation. During testing, a mass was applied to the CFRP cantilever beam to achieve a pre-stressed state, and the laser power densities varied from 500 to 1500 W·cm−2. Corresponding scanning electron microscope (SEM) tests were also performed on the ablation zone and fracture surface to analyze the failure mechanism. The results showed that the CFRP beam failed in compression at the bottom surface, which was due to a decrease in local stiffness and strength caused by heat softening, rather than by ablation damage on the top surface. The failure time decreased from 19.64 s to 6.52 s as the power density (500–1500 W·cm−2) and pre-stress loading (300–750 N·cm) increased, indicating that pre-stress loading has a more significant influence on the failure time of CFRP beams compared to power density.