# Repeated Low-Velocity Impact Properties of Hybrid Woven Composite Laminates

## TL;DR

This paper studies how hybrid woven composite materials behave under repeated low-velocity impacts and how their design affects damage resistance.

## Contribution

The study reveals how fiber type and orientation influence damage propagation in hybrid composites under repeated impacts.

## Key findings

- Damage in laminates includes delamination, matrix cracking, and fiber fracture as impact energy increases.
- Fiber type and lay-up direction significantly affect damage threshold and propagation rate.
- [(0,90)/(±45)]3s laminates show more damage expansion compared to (0,90)12 laminates.

## Abstract

Hybrid woven composite materials and structures have important application value in modern engineering because of their high specific stiffness, specific strength and excellent impact resistance. The mechanical properties of carbon/aramid fiber hybrid woven composite laminates under repeated low-velocity impacts were studied in this paper. This study aims to understand the behavior of these materials under repeated impact conditions and to evaluate their damage resistance and failure mechanisms. The materials and methods used are introduced in detail, including the preparation of samples, the experimental apparatus for impact testing, and the methods of damage assessment and data analysis. The experimental setup simulated real impact scenarios and followed procedures to collect and analyze data. The low-velocity impact tests were carried out in accordance with ASTM D7136 test standard. The experimental results show that with the increase in impact energy, the damage of laminates includes delamination, matrix cracking and fiber fracture. The damage threshold and damage propagation rate are affected by the type of fiber used and its lay-up direction in the composite. Compared with (0,90)12 laminates, [(0,90)/(±45)]3s laminates show more obvious damage expansion, which highlights the importance of fiber orientation in the impact durability design of laminates. The results can be used to design and optimize the structure of hybrid woven composite laminates.