Advanced FEA simulation of Mode II Interlaminar Fracture in Flax/Epoxy Multidirectional Laminate Composites Using the End-Notched Flexure (ENF) Test

Fadly, Muhammad Syaiful; Pramudia, Mirza; Pakpahan, Binsar Maruli Tua; Paundra, Fajar

doi:10.22075/macs.2026.38923.1917

Advanced FEA simulation of Mode II Interlaminar Fracture in Flax/Epoxy Multidirectional Laminate Composites Using the End-Notched Flexure (ENF) Test

Articles in Press

Document Type : Research Article

Authors

Muhammad Syaiful Fadly ¹

Mirza Pramudia ²

Binsar Maruli Tua Pakpahan ³

Fajar Paundra ⁴

¹ Department of Mechanical Engineering, Faculty of Engineering, Universitas Tadulako, Palu, Indonesia

² Department of Industrial and Mechanical Engineering, Faculty of Engineering, Universitas Trunojoyo Madura, Bangkalan, Indonesia

³ Department of Mechanical Engineering Education, Faculty of Engineering, Universitas Negeri Medan, Medan, Indonesia

⁴ Department of Mechanical Engineering, Faculty of Industrial Technology, Institut Teknologi Sumatera, Lampung, Indonesia

10.22075/macs.2026.38923.1917

Abstract

This study investigates the mode II interlaminar fracture mechanisms of flax/epoxy multidirectional laminates through finite element analysis (FEA) using the end-notched flexure (ENF) test. The laminates were configured as [(02/θ)6/02] with θ = 0°, 45°, and 90°, designed to minimize elastic couplings, although off-axis orientations introduced localized effects of limited significance. Fiber orientations perpendicular to the crack plane generated distinct shear energy dissipation patterns, although mode II remained dominant. Quantitative analysis revealed that the 0° configuration exhibited a higher Mode II strain energy release rate (GII) than the 45° and 90° configurations. In contrast, the 45° orientation significantly reduced the magnitude of GII due to shear–extension coupling and mixed-mode interactions. The ±45° fiber orientation also induced a redistribution and instability of the interlaminar shear stress field, leading to localized concentrations of strain energy near the specimen edges. The FEA results consistently captured the sensitivity of the strain energy distribution to the stacking sequence and confirmed Mode II as the primary fracture propagation mechanism in flax/epoxy laminates under ENF loading.

Keywords

Finite element analysis

Mode II interlaminar fracture

Flax/epoxy

Multidirectional laminates

End-notched flexure

Subjects