Fiber comparison
E-glass fiber vs Aramid fiber (Kevlar 49)
Every value below is a typical room-temperature figure with its source, test method and conditions — the same dataset that drives the calculators.
| Property | E-glass fiber | Aramid fiber (Kevlar 49) | Difference |
|---|---|---|---|
| Density | 2.54 g/cm³ | 1.44 g/cm³ | E-glass fiber — 76% higher |
| Young's modulus E | 72.4 GPa | 131 GPa | Aramid fiber (Kevlar 49) — 81% higher |
| Tensile strength | 3450 MPa | 3620 MPa | Aramid fiber (Kevlar 49) — 5% higher |
Where these numbers come from
- Daniel & Ishai, Engineering Mechanics of Composite Materials, 2nd ed.
Typical room-temperature values for learning and preliminary design; grades vary widely and a supplier datasheet always overrides a textbook figure. Confirm against the datasheet before design work.