Open Access

ARTICLE

Impact and Residual Flexural Properties of 3D Integrated Woven Spacer Composites

Mahim Masfikun Hannan, Deng’an Cai^*, Xinwei Wang

State Key Laboratory of Mechanics and Control for Aerospace Structures, Nanjing University of Aeronautics and Astronautics, Nanjing, 210016, China

* Corresponding Author: Deng’an Cai. Email:

(This article belongs to the Special Issue: Damage and Fracture of Polymer Composites)

Journal of Polymer Materials 2025, 42(3), 873-891. https://doi.org/10.32604/jpm.2025.064978

Received 28 February 2025; Accepted 24 July 2025; Issue published 30 September 2025

Abstract

This study investigates the low-velocity impact and post-impact flexural properties of 3D integrated woven spacer composites, focusing on their orthotropic behavior when tested along two principal directions, i.e., warp (X-type) and weft (Y-type) directions. The same composite material was tested in these orientations to evaluate the differences in impact resistance and residual bending strength. Specimens were fabricated via vacuum-assisted molding and tested at 2, 3, 5, and 7 J impact energies using an Instron Ceast 9350 drop-weight impact testing machine, in accordance with ASTM D7136. Post-impact flexural tests were performed using a four-point bending method in accordance with ASTM D7264. The absorbed energy increased from 1.97 to 6.98 J, and the panel damage area ranged from 121 to 361 mm² as impact energy roses. Specimens tested in the weft direction (Y-type) showed greater residual strength (up to 15.83 N) and displacement (up to 0.538 mm) than those tested in the warp direction (X-type). Ultrasonic C-scan imaging revealed localized matrix cracking and fiber failure damage patterns. Results emphasize the directional differences in impact resistance and residual bending properties, highlighting the importance of material orientation in structural applications. This study provides a foundation for utilizing 3D woven spacer composites in lightweight, damage-tolerant structural components.

---

Keywords

---