Al-Qadisiyah Journal for Engineering Sciences

Optimization of fiber orientation for reducing notch sensitivity in vacuum-assisted resin infused composite materials

Articles in Press

Document Type : Research Paper

Authors

Sabaa R. Al-Qubbanchi 1
Nassier A. Nassir 1
Amit Haldar 2, 3

1 College of Materials Engineering, University of Technology – Iraq, Baghdad, Iraq.

2 Department of Mechanical and Automobile Engineering, Technological University of the Shannon, Limerick V94EC5T, Ireland.

3 Hydrogen Energy Innovation (HEI) Research Group, Technological University of the Shannon, Limerick V94EC5T, Ireland.

10.30772/qjes.2026.164571.1724
Abstract
This work examines notch sensitivity in fiber-reinforced polymer composites, with attention to the role of fiber orientation and notch width. CFRP and GFRP specimens were fabricated by vacuum-assisted resin transfer molding (VARTM) using thermoset resin systems. The tested variables were fiber orientation (0o and 90o), notch width (0, 2, 4, and 6 mm), and tensile tests were carried out according to ASTM D638. The results showed that the 0° specimens had noticeably higher strength than the 90o specimens because the fibers were aligned with the loading direction. The 90o specimens showed lower strength and a more gradual failure response, mainly due to matrix-dominated behavior. Increasing the notch width reduced the ultimate tensile strength, especially for 4 and 6 mm notches, where fracture started near the notch tip because of stress concentration. Unnotched and 2 mm notched specimens provided the best balance between strength retention and practical manufacturability. These results confirm that careful fiber alignment and notch control are important for composite parts used in aerospace, automotive, and civil engineering structures

Keywords

Notch Sensitivity
Carbon fiber-polymer
Glass fiber-polymer
Vacuum-Assisted Resin
Composite materials
Crossmark
Subjects
Al-Qadisiyah Journal for Engineering Sciences

Articles in Press, Accepted Manuscript
Available Online from 06 August 2026

  • Receive Date 29 August 2025
  • Revise Date 09 February 2026
  • Accept Date 06 August 2026

Submit Manuscript

Guide for Authors

Article Processing Charges (APC)

Reviewers

Call for Reviewers

Contact Us