Shear and Interface Properties for Unidirectional, Woven, and Hybrid M21 Particle-Toughened Composites

Area of Science:

• Materials Science
• Composite Materials Engineering

Background:

• Toughened epoxy matrices like M21 are crucial for enhancing fracture resistance in advanced composites.
• Accurate material properties are essential for validating computational damage models in composite structures.

Purpose of the Study:

• To experimentally characterize the shear and interlaminar properties of hybrid laminated composite panels using the M21 epoxy system.
• To provide a dataset for validating computational damage models of these toughened composites.
• To establish a benchmark for modeling and simulation of M21-based hybrid interfaces.

Main Methods:

• In-plane shear behavior was assessed using ±45 (PM45) tension tests.
• Interlaminar fracture properties were determined via double cantilever beam (DCB) and end-notched flexure (ENF) tests.
• Parametric studies were conducted to identify key delamination parameters for numerical simulations.

Main Results:

• Hybrid laminates demonstrated high interfacial fracture toughness.
• Woven-woven and unidirectional-woven interface pairs exhibited significantly increased fracture resistance.
• Cohesive strength and fracture energy were identified as dominant parameters for delamination behavior.
• Specific values for these parameters were extracted for different interface types.

Conclusions:

• The experimental data enables accurate representation of damage initiation and propagation in finite element models.
• This work presents the first experimental dataset for M21-based hybrid unidirectional-woven and woven-woven interfaces.
• The findings serve as a critical benchmark for future modeling and simulation of toughened composite structures.