The ratio of stress to strain in the elastic region, quantifying a material's stiffness.
Young's modulus (E) is the slope of the linear portion of the stress-strain curve: E = σ/ε. Higher E means less deformation per unit load. Representative values: rubber ~0.01 GPa, PLA ~3-4 GPa, aluminium ~70 GPa, steel ~200 GPa. E is a material constant independent of specimen geometry.
E controls beam deflection directly (δ = FL³/3EI for cantilevers). In FDM, E is orientation-dependent: Z-direction E can be 30-40% lower than XY. Always use measured FDM E values in FEA; bulk-material values overpredict stiffness.
E applies only in the elastic (linear) zone. Beyond yield, the tangent modulus drops and E is invalid. Temperature strongly affects E: PLA softens above 55°C. Do not assume isotropic E for composite-filled filaments.
Related terms: Stress, Strain, Stiffness, Poisson's Ratio, Stress-Strain Curve
| Field | mechanics, engineering |
|---|---|
| Also called | Elastic Modulus, Modulus of Elasticity, E-modulus |
Engineer, author of The Big Book of 3D Printing and additive manufacturing expert