S2-Glass/Epoxy Unidirectional (MIL-HDBK-17)
VerifiedcompositeS-2 Glass/Epoxy unidirectional composite is a fiber-reinforced polymer consisting of high-strength S-2 glass fibers (a boron-containing variant offering improved performance over standard E-glass) embedded in an epoxy matrix, processed via autoclave prepreg for consistent quality and fiber alignment. This material is widely specified in aerospace, defense, and marine structures where the unidirectional fiber orientation maximizes load-bearing capacity along the primary stress axis, making it a workhorse for damage-tolerant primary structures that require both strength and repeatability per military specifications. Engineers select S-2 Glass/Epoxy over E-glass alternatives when thermal performance and fatigue resistance justify the higher material cost, and over carbon-fiber systems when cost, impact tolerance, or electromagnetic transparency are design drivers.
Compliance & Regulations
| Property | Value | Unit | Conditions | Source | |
|---|---|---|---|---|---|
Compressive Strength(σc) | — | Pa | L | — | |
Poisson's Ratio(ν) | — | - | notes | — | |
Shear Modulus(G) | — | Pa | notes | — | |
Ultimate Tensile Strength(σUTS) | — | Pa | L | — | |
Young's Modulus(E) | — | Pa | L | — |
| Property | Value | Unit | Conditions | Source | |
|---|---|---|---|---|---|
Density(ρ) | — | kg/m³ | — | — |