Fiber comparison
Aramid fiber (Kevlar 49) vs Carbon fiber (T300)
Every value below is a typical room-temperature figure with its source, test method and conditions — the same dataset that drives the calculators.
Which to choose
Aramid's strength is in tension and impact — it is what stops bullets and resists abrasion — but it is weak in compression and hard to cut or machine cleanly. Carbon is stiffer and behaves properly in compression. Carbon for stiff structure; Kevlar where impact, puncture or ballistic performance governs, often hybridised with carbon.
| Property | Aramid fiber (Kevlar 49) | Carbon fiber (T300) | Difference |
|---|---|---|---|
| Density | 1.44 g/cm³ | 1.76 g/cm³ | Carbon fiber (T300) — 22% higher |
| Young's modulus E | 131 GPa | 230 GPa | Carbon fiber (T300) — 76% higher |
| Tensile strength | 3620 MPa | 3530 MPa | Aramid fiber (Kevlar 49) — 3% 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.