Fiber comparison
Aramid fiber (Kevlar 49) vs S-2 glass fiber
Every value below is a typical room-temperature figure with its source, test method and conditions — the same dataset that drives the calculators.
| Property | Aramid fiber (Kevlar 49) | S-2 glass fiber | Difference |
|---|---|---|---|
| Density | 1.44 g/cm³ | 2.46 g/cm³ | S-2 glass fiber — 71% higher |
| Young's modulus E | 131 GPa | 86.9 GPa | Aramid fiber (Kevlar 49) — 51% higher |
| Tensile strength | 3620 MPa | 4890 MPa | S-2 glass fiber — 35% higher |
Where these numbers come from
- Daniel & Ishai, Engineering Mechanics of Composite Materials, 2nd ed.
- AGY S-2 Glass product datasheet
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.